Answer from Pat:
Since you went to San Luis Obisbo in April or May and were struck by a very fragrant plant which you smelled everywhere, my guess is that it was Victorian box (Pittosporum undulatum). Pittosporum undulatum is a large shrub or small-to-medium size evergreen tree from eastern Australia often found in old established gardens in the mild coastal climates of Southern California. It’s invasive in warm-winter climates, thus it often seeds itself in irrigated gardens but cannot survive in wild lands unless there is a stream or other water source. It is drought-resistant along the coast, but needs regular irrigation inland.

Victorian box has a number of virtues. It has dense, clean green foliage, no pests, and creamy-white blossoms in spring that are not particularly showy but are wonderfully fragrant. One can clip it into a high informal hedge or let it grow into a tree. If a hedge ever gets too tall you can cut it down lower, even all the way to the ground if you want, and it will sprout and grow again. When this shrub or tree is in bloom in spring and when it has spread through many gardens, the utterly delightful fragrance may waft on the breeze throughout an entire town for about a month every spring. It is especially strong in the evening. Bunches of round seed pods take the place of flowers in summer. In fall they turn orange, and in December or January, they open and sticky seeds onto the ground or pavement. Birds love the seeds and spread them around to many gardens. The seeds also stick to animals’ feet and people’s shoes which are additional ways of spreading them. The seeds sprout easily in the winter rains. Victorian box is a pest plant in Hawaii since regular rainfall allows it to proliferate in wild lands. Here in California our seasonal rains confine it to irrigated gardens in USDA Zones 9 and 10. It cannot survive cold winters. If you live in Zone 9 or 10 you should be able to grow this tree, but check first that it is not on the list of noxious pest plants in your region. When rainfall is year-round, exotic species that need moisture and have invasive characteristics can spread into wild lands where they can choke out natives.

Related posts:

1. Growing Lilac (Syringea vulgaris) in Southern California
2. Planting for Fall and Year-Round Color in Southern California
3. Old Time White, Fragrant Freesias

Many spectacular trees and shrubs from mild regions around the world are well adapted to growing in our coastal Mediterranean climate. Nonetheless, when housing developments are originally landscaped, planners usually choose the most pedestrian trees and shrubs since they are non-controversial and easy to find in nurseries. When these original trees and shrubs die or are in need of replacement due to disease, invasive roots, or other problems, a unique opportunity arises to create a more exciting and colorful landscape.

Colorful trees and shrubs can be arranged in the landscape in a variety of ways. One can dot them throughout the landscape or, alternatively, create a more unified look by planting in drifts and choosing a specific tree variety for each street. We recommend a combination of these approaches to be accomplished by mixing shrubs on banks in attractive color schemes, using drifts in some areas, and gradually replacing street trees by planting solidly with one specific and different flowering tree chosen for each street. Thus you would have a white-flowered street, yellow-flowered street, purple-foliaged street, pink-flowered street, red-flowered, salmon-flowered street and so forth. The flowers also would occur at different times of year, thus lending color year-round.

Flowering subtropical trees and shrubs, once established, often become more drought resistant than the trees and shrubs they replace. Some of them are slow growing, others are fast, some take a few years to bloom, others bloom immediately and, in some cases, year-round. Flowering trees, once mature, can become a lasting gift of beauty and excitement for generations to come. It is with these ideas in mind that we offer the following plant lists and suggestions.

CURRENT GOALS:

• Replace trees such as carrotwood, pine, eucalyptus, camphor, liquidambar, and sycamore trees that need to be removed due to problems with invasive roots, height, or disease.
• Provide a list of alternative street trees as well as trees and shrubs for slopes.
• Recommend placement according to height and exposure.
• Take into consideration these factors:
  • Low maintenance
  • Drought tolerance
  • Colorful flowers or foliage
  • Pleasing appearance when seen from homes above
  • Basic color scheme: Pink, blue, yellow, white, lavender, with splashes of red

PLAN FOR FIRST YEAR:

Replace plants in front yards with better choices.

SURVEY OF AREAS:

Here is a survey of the landscape trees and shrubs. Below this survey, you will also find lists for banks that can be used as guides for all areas, arranged according to the heights of banks and of plants.

Remove stump and plant Chinese Fringe Tree (Chionanthus retusus) or Indian Hawthorne Tree (Rhaphiolepis ‘Majestic Beauty’) one of the best small trees ever developed, but needs to be on tall enough trunk.

Shiny Xylosma (Xylosma congestum) Tall camellia-like hedge is –Repeat planting wherever a dense green screen is needed with neat foliage. This plant is well adapted to west end of lower streets to screen fence and main road.

Problems that can occur on slopes:

Over watering can cause irregular growth and weakened trunks on Pink Melaleuca (Melaleuca nesophila.) Improve their look by cutting one or two trunks from each clump every year and rounding off the foliage.

Suggestions for sunny places on slope: Dwarf Bottle Brush –(Callistemon citrinus ‘Perth Pink’), Dwarf Pohutukawa (Metrosideros villosa ‘Tahiti’) close to top of bank/slope, Dwarf Tea Trees (Leptospermum scoparium.) See list below for varieties.) and Blue Plumbago (Plumbago auriculata ‘Royal Cape’),  Cherry Plum (Prunus ceracifera ‘Nigra’), an ornamental purple-leaved plum, bearing white flowers in spring followed by abundant small round plums, could be planted at base of the slope, as we discussed. However the best use for it would be as one of the chosen street trees. Reputed to be better inland than along the coast, there are nonetheless many beautiful specimens close to the ocean. A cold winter such as we just had makes this tree more eye-catching than usual. It is especially nice when seen against green backgrounds.

Chinese Flame Tree (Koelreuteria bipinnata), described in lists below, would make a good replacement for Carrotwood (Cupaniopsis anacardiodes) as a street tree.

What to do about narrow spaces between buildings:

Hawaiian Wedding tree or Sweetshade (Hymenosporum flavum): Tall, narrow upright growth makes this good for narrow spaces, where it even can be planted in groves. A massive display of single, yellow, fragrant flowers covers the branch tips in spring and early summer. Though reputed not to grow in wind there are excellent specimens growing within a quarter mile of the ocean.

Plant Weeping Bottlebrush (Callistemon viminalis ‘McCaskillii’ ) on banks. Choose and place this very large shrub according to height requirement. Improved bottlebrush varieties are more shrubby with better flower color. They can be purchased or trained into single-trunked, highly colorful, trees or allowed to grow as massive multi-trunked shrubs. (Both uses are discussed below.)

Large, high slopes

Make sure irrigation pipes such as white PVC pipes are covered with a thick layer of rough-textured mulch such as tree trimmings to improve look and encourage growth of ground- covers.

Plant Floss Silk Trees (Chorisia speciosa) and/or other colorful trees at the base of h ills, where height won’t destroy views. It is not necessary to purchase the grafted Floss Silk Trees.  Prominent thorns on green trunks of the species are ornamental conversation pieces.

Plant Tipu Trees (Tipuana tipu) on large slopes. Also plant a selection of colorful shrubs from list below.

Covering existing eyesores:

Plant Bottle Brush or Blue Plumbago (Plumbago ‘Royal Cape’) to cover stump of Pink Melaleuca (Melaleuca nesophila) which is good in coastal zones.

Replacing old woody plants that have been injured by improper pruning:

Remove Mirror plant (Coprosma) hedges and replace with Dwarf Indian Hawthorne (Rhaphiolepis ‘Ballerina’) on 3-foot centers. (Deadhead and fertilize after bloom. Pinch back tips after bloom, but do not sheer or heavily prune this plant until it spreads out and covers space. Do not allow gardeners to prune this plant into a round ball.) Retain the gray-foliaged Ballotta (Ballotta pseudodictamnus) and Lily of the Nile (Agapanthus) but remove straggely plants that spoil the appearance.. Retain Pigmy Date Palms (Phoenix roebelenii). Feed these palms annually in May with Scotts Palm Food and cut off damaged fronds. Given proper care, these elegant palms should become more valuable and attractive with age. Replacement at this time would be expensive and is unnecessary.

NOTE: If it should in future be necessary to replace these palms due to unsightliness or disease, then at that time, replace each clump with 3 Windmill Palms (Trachycarpus fortunei), but this action is not recommended unless absolutely necessary. (Windmill palms are hardy, i.e.: they can go through colder winters than most other palms. They are attractive when grown in the corners of beds, but are currently more difficult to find and more expensive to purchase than Pygmy Date Palm. They do not look good when grown in windy locations.)

Replanting of slopes to improve appearance and stablilize soil:

Remove Hop Bush (Dodonia viscosa ‘Purpurea’) Plant a tall flowering tree Markhamia Tree (Markhamia lutea, M. hildebrandii)– in a location at base of high bank so it does not cut into views of houses higher on hill. Cover stumps such as ficus stumps from removed trees by planting Bottle Brush (Callistemon citrinus ‘Improved’ or ‘Splendens’) as the large-size screen here, or New Zealand Christmas Shrub (Metrosideros collina ‘Spring Fire’) or choose from list below according to height and size needed.  Replace Pink Powder Puff (Calliandra haematocephala) Choose shrubs for bank from list below in order to fill smaller spaces and to screen bank and fence.

Beautifying intersections:

A prominent position such as an intersection might be a good place for planting a really spectacular tree, even if it took a few years to bloom.

In protected from wind, plant: Cape Chestnut (Calodendrum capense) Briefly deciduous, this stunning round-headed tree is magnificent in bloom but best out of wind. It can take as much as 5 years to bloom and needs regular water, but to plant this tree is to give a lasting gift to the landscape..

Care for existing bougainvilleas that are failing to thrive.

When bougainvilleas do not grow at am appropriate rate, cold weather in the previous winter might have slowed growth. If bougainvilleas do not grow well when the weather warms up, the cause might be that their needs have not been fulfilled. Certain specific varieties of Bougainvillea, (for example: ‘San Diego Red’, and Bougainvillea spectabilis )can become very drought-resistant once established in deep soils, but during the first three years they need plenty of irrigation plus periodic fertilizer to push roots down deep and get going. Good bougainvillea varieties for banks, besides the large selections above, include the more compact types such as ‘La Jolla’, ‘Crimson Jewel,’ and ‘Temple Fire. Large types include ‘Lavender Queen’, ‘Don Mario’, ‘James Walker’, and ‘Orange King.”  Bougainvilleas need a hot spot. Unfortunately, they often become infested with roof rats whereas most shrubs do not.

When replacing diseased pine trees I an area of low irrigation, consider Naked Coral Tree (Erythina coralloides). This coral tree, naked in winter, has often been used on banks and tends to keep everyone happy since it offers two different looks during the year. It is covered with large, light green leaves in summer, thus creating a screen and offering shade. These go yellow and drop in fall revealing a bizarre branch structure bearing black thorns, and bearing spectacular, spiky, brilliant-red blossoms at the tips of branches for a long season in spring. These eye-catching blossoms attract hummingbirds and orioles. Good on banks where its flowers can be admired but the thorns not encountered. Eventual size is 30 feet, but easily controlled by pruning. Take out any unwanted branches after bloom.

A colorful planting for a large slope at intersection

Add color on large slope with drifts of Pride of Madeira (Echium candicans), Lantana ‘Radiation’, and red Bougainvillea ‘La Jolla’.

Replacing pine trees

Marina Strawberry Tree (Arbutus ‘Marina’), is an evergreen, drought-resistant, Mediterranean tree that is appropriate for replacing pine trees that have died from beetle attack. It provides color from red bark, pink flowers, and ornamental red fruit. Rounded shape will make a good screen and compliment any surviving pine trees.

Another slope:

Replace dead trees with Tipu Tree

When choosing street trees, pick one that will work for an entire

street: Good choices: New Zealand Christmas Tree (Metrosideros excelsa) or Chinese Fringe Tree (Chionanthus retusus)

Plant colorful shrubs as large ground covers on slopes – Use Echium, tea trees, euryops, plumbago, and smaller bottle brushes from lists below.

Street and slope:

Plant Street trees, one for each property: Cherry Plums (Prunus ceracifera ‘Nigra’) . Trim hedges behind walls to 1’ higher than walls.

Slope: Screen with colorful plants from list below.

NOTE: “Spiral ginger” with red flowers died from frost. Judging by description, this was Lobster Claw (Heliconia pendula) Possible source: Kartuz Greenhouses in Vista or look on Internet by Googling the botanical name as cited above. In future protect from expected frost by covering with sheet on cold nights, remove in morning before sun strikes plant.

Excellent choice of vine to grow over sunny walls: Lavender Trumpet Vine (Clytostoma callistegioides).

REPLACEMENTS FOR REMOVED STREET TREES:

(Highly recommended choices are marked with asterisk. Those without asterisk are additional possibilities.)

SMALL TREES:

• *Bottle Brush (Callistemon viminalis ‘McCaskillii’): Purchase specimens pruned as a single-trunked tree.
• *Bronze Loquat (Eriobotra deflexa): Small, tough, evergreen tree with bronze new foliage and white flowers in spring.  Try to get single-trunked specimens for use as street trees. Easy to grow.
• *Cherry Plum (Prunus ceracifera ‘Nigra’): Ornamental purple plum with deep red, almost black foliage, briefly deciduous, bearing white flowers in spring followed by abundant small round plums. Though reputed to be better inland, beautiful examples of this tree are growing along the coast, especially handsome when seen against green foliage.
• Pineapple Guava (Acca sellowiana ‘Coolidge’): Self fruiting pineapple guava that can occasionally be found pruned up as a tree. Fragrant flowers with sweet, edible petals, are followed by good-tasting fruits. Beloved by most homeowners and brings birds. This tree is usually sold as a large multi-trunked shrub but occasionally one can find single-trunked specimens which make good small street trees, which will gradually grow larger and seldom if ever require replacement.
• *Rhaphiolepis indica ‘Magestic Beauty’ is the best choice when a very small street tree is needed. See this tree growing at the Lumber Yard, an upscale shopping mall on the right hand side of Old 101 going north through Encinitas. These specimens in the Lumber Yard shopping mall are 20 years old, and have a beautiful umbrella shape, covered with bright pink blossoms in spring. Sheer tops removing all spent blossoms and a little foliage once a year, after blooms fade, never before bloom.
• Sky Flower (Duranta erecta) Stunning blue flowers that attract hummingbirds and butterflies are followed by colorful show of yellow-gold, poisonous but very attractive fruits. Average to low water requirement. (Usually sold as multi-trunked shrub, but sometimes as single-trunked tree.)
• String of Pearls (Duranta stenostachya’Sarasota’) Larger leaves and flower clusters, are followed by long strings of attractive, hanging, golden “pearls”. Eye-catching conversation piece. Flowers are sweetly scented, but the highly ornamental fruits are poisonous. (Usually sold as multi-trunked shrub, but sometimes as single-trunked tree.)

MID-SIZE TO LARGER STREET TREES

(Variable situations of soil and space tend to influence size of trees. Eventual sizes do not differ hugely from that of the trees they are replacing, and in many cases are much smaller. Camphor tree, for example, that is being replaced, has an eventual size of 50 feet high and 60 feet wide, whereas the eventual size of Chinese Fringe Tree is only 20 feet.)

• *Bottle Brush (Callistemon citrinus ‘Splendens’ and C. citrinus ‘Improved’): A thick, compact head of foliage and plentiful masses of bright-red, bottle-brush-shaped flowers, blooming in waves several times a year make this a stunning street tree when pruned as a single-trunked tree. Brings birds. (Grows to 20 feet.)
• *Flamegold (Koelreuteria elegans, K. formosa): A virtuous, deeply rooted, 20-30 foot tall tree, adapted to growing in lawns or as a street tree, best bloom where protected from wind. May be evergreen, but usually drops leaves briefly in winter. (A similar variety, Chinese Flame Tree [K. bipinnata] is equally as beautiful but larger.) On both trees, insignificant panicles of yellow flowers in June are followed in fall by a magnificent, long-lasting show of orange to salmon-pink seed pods that look as if a bougainvillea had gotten tangled up into the tree and then suddenly burst into bloom. (It is very important not to get K. paniculata, which is a worthy, hardy tree in cold-winter areas of the Southwest, but lacks the fall beauty of K. bipinnata or K. elegans, since its seed pods turn an ugly brown, though one variety, called ‘Rose Lantern’ has pods tinged with pink.)
• *Chinese Fringe Tree (Chionanthus retusus): Clusters of  fringelike white flowers cover branches of this stunning, small—to 20 –feet-tall)—tree in spring. In fall leaves turn bright yellow before falling. (Reputed to flower better inland, but the parking lot of Salk institute is planted solidly with this tree, a breathtaking sight in spring.)
• *Evergreen Pear (Pyrus kawakamii):Though this tree is very subject to occasional die-back of branches due to fire blight, in recent years it seems to have been less prone to damage and has bloomed exceptionally well in our area. Leaves may hang on year-round but sometimes drop off just before the tree bursts into a glorious show of shining white flowers in February. Needs little pruning and stays small for many years. 15 to 30 feet high at most, usually smaller for many years. Best show of bloom when winters are dry.
• * Gold Medallion Tree, Crown of Gold Tree,  (Cassia leptophylla, Senna spectabilis): Round bunches of blooms on rounded, briefly-deciduous tree over a long period, spring to fall. A popular tree in our area, quite drought resistant, eventually to 20 feet tall but well-adapted as street tree and used as such in some areas.
• *Hong Kong Orchid Tree (Bauhinia blakeana): Strong fall into winter color from brilliant orchid-pink to rosy purple orchid-shaped flowers on a natural umbrella-shaped tree. Kidney-shaped gray-green leaves drop briefly just prior to bloom. Needs good drainage. 20 feet high and wide but tends to stay small for a long time making it a better street tree for Brisas Del Mar than the equally spectacular purple orchid tree (B. variegata), which is larger (to 30 feet) and blooms in spring. The latter however is the one most frequently planted as a street tree and it is glorious where springs are reliably warm. Prune bauhinias after bloom by trimming out crowded growth. Never prune before bloom.
• * New Zealand Christmas Tree (Metrosideros excelsa ‘Gala’): New foliage is gray green against dark evergreen tree with red summer flowers. This variety, if available, has bright yellow in center of each leaf and dark red flowers have bright yellow stamens. Good street tree, but not for crowded spots. The species itself is also good and often sold as a street tree. (To 30 feet.)
• *Pink Trumpet Tree (Tabebuia impetiginosa ‘Pink Cloud’): Once this tree has matured it gives an incredible display of pink flowers in spring. Planted in center front of Scripps Hospital. Fast growing to about 15 feet, then slower growing to 20 or 30 feet. Leaves briefly drop just before the tree flowers in spring on bare wood.  The older it grows the more beautiful this tree becomes.
• *Redbud (Cercis canadensis ‘Forest Pansy’): Purple foliage catches the sunlight in a stunning way. Deciduous in winter, followed by an early spring show of purple-pink, pea-shaped flowers that emerge straight from the bark, sometimes even from the trunk. Drought-resistant once established but can accept garden water. Slow growing to 20 or 30 feet.
• *Weeping Bottle Brush Hybrid (Callistemon viminalis ‘McCaskillii’) Waves of flowers year-round bring mockingbirds, orioles, and flocks of hummingbirds for their nectar.  Improved varieties, such as this one, are bushy with brilliantly colorful flowers. Though sold as shrubs, they can also be purchased as trees. These have been pruned up on a single trunk to become very attractive street or garden trees, that are not nearly as tall as the species.  Drought-resistant once established but adapted to garden water. Needs good drainage. Grows to 20 feet.

CHOICE TREE FOR GRADUAL REPLACEMENT OF PINES

• Marina Strawberry Tree (Arbutus ‘Marina’): Evergreen tree with pink flowers in fall followed by decorative, round, red, edible (though tasteless) fruits providing food for birds and year-round color. Drought-resistant tree with stunning red bark that peels like a madrone. (This fairly new tree might be suitable as a street tree but is untried. It may grow to 40 feet but probably much smaller.)

COLORFUL TREES TO PLANT AT THE BASE OF TALL BANKS

• African Tulip Tree (Spathodea campanulata): Reputed to have fast growth but yellow ones are slower and are being used as street trees in some areas. It has moderate water needs combined with bunches of large, spectacular flowers over a long season. Best out of strong winds. Choose either yellow-orange or red specimens, red being the most spectacular but perhaps larger and faster growing. The red variety could become invasive after a few years, so is better on open ground away from houses.
• Cape Chestnut (Calodendrum capense): Handsome dark green foliage may be briefly deciduous or may hang on through winter on this very showy, round-headed tree, that is magnificent in bloom and best out of wind. It can take 5 years after planting for this tree to bloom, which is why it is not often enough planted. It needs regular water but can survive on less. To plant this tree is to give a lasting gift to the Del Mar landscape. (Great example near flamingo pool, San Diego Zoo.) Flowers are feathery and arise in panicles as big as baseballs,  rosy-lilac to pink in color. They drench the entire top of this neatly shaped, rounded tree in early spring or summer.
• Floss Silk Tree (Chorisia speciosa): Spectacular fall bloom, orchid-colored flowers all over the top of the tree after leaves briefly drop, especially good bloom if you can let it go dry in late summer. Seed pods and flowers bring hummingbirds. Highly recommended on the tall banks. Grafted specimens have no thorns but thorny trunks are ornamental and these trees usually bloom young.
• Jacaranda (Jacaranda mimosifolia): One of our best flowering trees. Likes reflected heat.
• Lemon Bottle Brush (Callistemon citrinus ‘Splendens’ or ‘Improved’): The blooms are more upright than weeping. This selection is sold pruned up as a tree or it can be grown as a very large, multi-stemmed shrub or screen.
• Markhamia or African Trumpet Tree (Markhamia lutea, M. hildebrandii): Evergreen tree that is fast-growing, tall and narrow for 10 years, then spreading and slow-growing. Profusion of golden-yellow trumpet blooms from July to December followed by prominent hanging pods. Gaining popularity as street tree due to upright shape. Blooms best after dry winter. Likes well-drained soil.
• Weeping Bottle Brush (Callistemon viminalis): Evergreen, weeping tree that is drought resistant and brings hummingbirds, orioles and mockingbirds. Waves of bloom year round.

COLORFUL SHRUBS AND TREES FOR BANKS:

VERY LOW SHRUBS: (Up to 3 feet tall, not higher than 4 feet.)

Use these as fillers on banks or at the tops of banks.

(Sensitive to frost, but if you place these high on banks they should be in a frost-drained site, thus safe from frost.)

• Bottlebrush (Callistemon viminalis ‘Little John’) 3 feet tall and wide. Very colorful waves of flowers fall, winter and spring, on superior dwarf bottlebrush with weeping habit.
• Dwarf New Zealand Tea Tree (Leptospermum scoparium ‘Nanum Ruru’): 2 feet tall and wide. Dense growth. Dark-pink single flowers in winter, spring,  into summer.
• Dwarf New Zealand Tea Tree (Leptospermum scoparium ‘Pink Cascade’): 1 foot tall and 3-to 4-feet wide. Single pink flowers,  sprawling, weeping, cascading growth.
• Dwarf Pohutukawa (Metrosideros villosa ‘Tahiti’) (to 3-feet tall and wide): No pruning needed. Gray-green leaves and clusters of orange-red flowers in spring, with sporadic rebloom. (Sensitive to frost, but high on banks should be a frost-drained site.)
• Groundcover New Zealand Tea Tree (Leptospermum scoparium ‘Horizontalis’): 3 to 4-feet tall, 12 feet wide. Profuse show of white blossoms on drooping branchlets, spreading plant, makes good bank cover.
• Groundcover New Zealand Tea Tree (Leptospermum scoparium ‘Snow White’): 2 to 4-feet tall, 4 to 5-feet wide. Double white flowers with green centers on compact, spreading plant
• Shrubby New Zealand Christmas Tree (Metrosideros collina ‘Fiji’): is even smaller, just 2 feet tall and wide.  Available from Monrovia Nursery. Red powder-puff flowers, winter and spring, bring butterflies.

LOW SHRUBS: (3 to 5 feet tall)

(Use these on low banks and at the top of tall banks so that they create a screen but do not hide views.)

• Bottle Brush (Callistemon citrinus ‘Compacta’): Mounded plant to 4 feet wide and high.
• California Lilac (Ceonothus ‘Concha’): Good blue color. This one can take garden irrigation without dying
• Matilija Poppy (Romneya coulteri): Superior, drought-resistant yellow-centered white poppy flower for banks. Gray foliage should be cut down in November if possible and will spring again from ground to bloom in spring through summer.
• Radiation Lantana (Lantana ‘Radiation’): 3 to 5 feet high and wide and one of the better and most colorful lantana’s for banks. Drought-resistant with long bloom season. Flowers are yellow, orange, and pink. Looks good when mixed with blue plumbago and red bougainvillea.
• Yellow Bush Daisy (Euryops pectinatus ‘Viridis’ or ‘Green Gold’): Long-lived woody, drought-resistant, evergreen shrub, native to South Africa,  3-to 6-feet tall and wide bears yellow daisies over a long season, mainly in winter. Shear off faded flowers and a little of the green growth once a year in June.  (Provides good yellow color to go near blue Pride of Madeira and pink and white dwarf tea trees.)

MID-HEIGHT SHRUBS:  (5 to 10 feet tall)

• Bottle Brush ( Callistemon  ‘Canes Hybrid’): 10 feet tall, 15 feet wide. A big screen, measure so eventual height hits at the right level to see over. Narrow leaves and arching branches with pink-tinged foliage, soft pink bottle-brush flowers in late spring, early summer. Easily pruned to a tree shape. Can be kept smaller by pruning but why have that problem? Instead plant where it can grow to full size.
• Bottle Brush (Callistemon viminalis ‘Captain Cook’): Dense, rounded plant to 6 feet tall and wide.  For border, hedge, or screen. (‘Red Cascade’ is similar with large abundant rosy red blooms.)
• Geraldton Waxflower (Chamaelaucium unicatum ‘Vista’): Pink flowers for long season from fall to summer on rounded drought-resistant shrub, to 6 feet tall, for full sun. Cut back after bloom.
• New Zealand Tea Tree ((Leptospermum scoparium ‘Silver and Rose’): Dense growth habit to 4-to 5-feet tall and wide. Rose-pink, green-centered flowers with bright gray-green foliage. Excellent plant to use as screen high on bank.
• New Zealand Tea Tree (Leptospermum scoparium ‘Gaiety Girl’): Slow growing to 5 feet tall and 4 feet wide. Double flowers are pink with a dash of lilac.
• New Zealand Tea Tree (Leptospermum scoparium ‘Pink Damask’): Dense growth habit to 6 to 8 feet tall and 4 to 5  feet wide. Double ruby-red flowers red tinged leaves. Particularly good screen plant.
• Plumbago (Plumbago auriculata ‘Royal Cape’): Makes a mounding shrub 6 feet tall, 8 to 10 feet wide with large rounded deep blue flowers blooming over a long season. Excellent bank cover when placed away from paths. Give it room to spread. Named varieties are not invasive like the older unnamed type. Good mixed with lantana.
• Pride of Madeira (Echium candicans): (5 to 6 feet tall and 8 to 10 feet wide.) Blue spiky blooms on a gray woody shrub. Dot these around on banks. They will spread from seeds.

TALLER SHRUBS: (8 to 12 feet tall, including one to 20 feet high.)

• Bottle Brush (Callistemon citrinus ‘Pink Perth’): 8 to 10 feet tall, 5 to 8 feet wide. Weeping foliage, pink flowers in spring. Use low on banks as big, colorful screen.
• Bottle Brush (Callistemon citrinus ‘Splendens’ and C. citrinus ‘Improved’):
• Massive shrub, 10 to 15 feet tall and wide. Use low on banks as big, colorful screen. Brings birds.
• New Zealand Christmas Shrub (Metrosideros collina ‘Spring Fire’): 8 to 12-feet high, 6 to 10-feet wide. Gray-green foliage with a profusion of showy flowers in late spring to early summer bringing butterflies and birds. Makes attractive hedge, but is sensitive to frost. Use high on banks, thus safe from frost.
• Weeping Bottle Brush, (largest shrub form) (Callistemon viminalis ‘McCaskillii’): 20 feet tall, 15 to 20 feet wide. Flowers bring mockingbirds, orioles, and flocks of hummingbirds for their nectar.  Improved varieties, such as this one, tend to be thickly bushy with brightly colorful flowers. Drought-resistant once established but adapted to garden water.

Related posts:

1. Colorful Taller Shrubs And Trees For Banks
2. Colorful Low Shrubs And Trees For Banks
3. Colorful Mid-Height Shrubs And Trees For Banks

Question from Rachel:

On to the lilac tree/bush: I bought a white lilac plant a few years ago, and at the time it was exploding in flowers. I planted it in a corner of my garden where it flourished for 2 years (very green and leafy) but it never created a single blossom. I did some online research and read that in my zone (23) lilacs should do quite well, but that they needed a lot of sun. So I moved the lilac to the center of the backyard. It has not done well. Many of the leaves are looking crispy and burnt at the ends, and while the plant is covered in little green buds, they frequently turn brown and flake away. Am I not watering enough? Should I move the lilac back into the shade? Or should I forgo lilacs altogether?

Answer from Pat:
Many folks who grew up in cool-season climates and moved to Southern California wish they could grow lilac (Syringea vulgaris) here. If one chooses a low-chill variety, such as ‘Lavender Lady’ or ‘Alba’ that are adapted to growing in a Mediterranean climate, it is possible to grow lilac successfully and bring it into bloom in Southern California, but you need to live in Zone 22 (the Los Angeles Basin is Zone 22) or in a zone of even colder winter temperatures than that, such as Zone 21. Lilac blooms beautifully in Julian, for example, and is very fragrant there. In hot interior climates it’s better to grow lilac in part shade and not full sun, so I don’t think sun or shade was the cause of your lilac not blooming. I think it was temperature. Lilac is actually pretty well adapted to our soil since it prefers soil that is slightly alkaline and if you have acid soil you should add a little Dolomitic lime to it to make it sweeter. Lilac also needs moist soil and regular irrigation. It is not drought-resistant.

One must cut lilac back after bloom or pick all the blooms with long stems on them leaving some buds for new growth in order to create more blooming wood for the following year. “Prune after bloom never before” is the rule with lilac. (If you have a gardener who regularly prunes everything in sight that’s why your plant didn’t bloom because he cut off all the blooming wood.) However, the main reason eastern lilac fails to bloom in mild frost-free climates is because the plants didn’t get enough winter chill. You live in Zone 23 which is a mild coastal zone good for avocados your garden simply does not have enough winter chill to successfully make lilac bloom, except in a cold pocket, or microclimate if you have such a spot. One of my daughters lives in Zone 23 and had three lovely lilacs in her garden. They bloomed for 3 years but where not very fragrant, then stopped blooming last year and this year they died. I do not consider this a good recommendation for a plant to grow here in Southern California.

Even when lilac does bloom the fragrance is not as good as if it were growing in a climate with adequate winter chill. Even without winter chill some folks have had success forcing their plants to bloom by withholding water in fall. (Usually lilacs need regular irrigation, but fall drought can force lavender to make buds for spring bloom.) Because of all these difficulties I don’t recommend lilac as a wise choice for local gardens unless you live in a place like the San Gabriel Valley or Ramona where winter frosts are a common occurrence.

I suggest you look around for something to grow that will please you as much or more than lilac. My suggestion is to build a pergola this fall and plant Chinese wisteria (Wisteria sinensis ‘Cooke’s Special’) bare root in January. Feed it, water it well for the first three years, and prune and train it carefully as I describe in my book. Every February and March, you will have masses of purple bloom (almost the same shade and shape as lilac) fragrance to die for, and eventually armloads of woody boughs covered with blooms to bring into the house. Once established and trained, wisteria is very drought-resistant. It also attracts birds.

Thank you so much for telling me about your prolific ‘Bearss’ lime tree. Delighted to know my advice helped.

Related posts:

1. Eastern Lilacs
2. Planting for Fall and Year-Round Color in Southern California
3. Don’t Bother Growing Rhubarb in Southern California

Answer from Pat:
You live in an excellent climate zone. You certainly can create a garden with year-round color, including fall color, but I am sorry to tell you that now is not the time to plant for fall. Beginning in September this is the time to pull out summer annuals, amend and fertilize and replant for winter and spring. It is also the time to weed, cut back, divide, and replant perennial gardens for winter and spring. If you plant the right annuals and bulbs now you can have color from annual plants and bulbs all winter long into spring. In the annual garden, the plants you put into the ground now don’t need to be in bloom, but they must be cool-season plants. Some annual plants to put in now include primroses, Iceland poppies, cinerarias, hollyhock, snap dragon, calendula, foxgloves, stock, pansies, and sweet alyssum. Now is also the time to plant wildflowers from seeds and to plant bulbs such as ranunculus, daffodils, narcissus and all the wonderful South African bulbs that will come back year after year in our gardens. (You can also plant hyacinths, tulips, and Dutch crocus but these need pre-chilling in the refrigerator for 6 weeks prior to planting.) The sooner you get things into the ground and the more regularly you feed them—wildflowers however don’t need fertilizer—the more likely you will be to have blooms prior to the holidays. If you manage that they will bloom all winter into spring, with April being the height of bloom, but the spring garden will continue in full bloom through May.

Your question is an excellent one. It gives me a chance to help many people who did not grow up here in California and thus don’t understand the rhythm of Southern California gardening. As my book explains in detail, in Southern California we garden year-round, but we plant cool-season (or “winter”) crops and flowers in fall, and we plant warm-season (or “summer”) crops and flowers in spring. Right now, for example, in October we are in the very midst of our fall planting season. Though our mild temperatures permit planting to continue through November, our fall months are already two-thirds over, thus as a general rule now is not the time to plant for fall color. This should have been done months or years ago. Fall is the time when we should be looking ahead and planting for spring or, alternatively, we should be planting permanent climbers, trees, and shrubs for the full future life of our garden. Much of our best seasonal color comes from permanent woody plants. Among fall blooming trees are Chinese flame tree (Koelreuteria elegans; K. henryii), floss silk tree (Chorisia speciosa), and Nile tulip tree (Markhamia lutea), among climbers are Hardenbergia ‘Happy Wanderer’ and flame vine (Pyrostegia venusta), and among colorful shrubs are Copper canyon daisy (Tagetes lemonii), firethorn (Pyracantha), and euryops. Watch for other permanent flowering plants as you drive around or go to botanical gardens to see what is in bloom at each season of the year. Except for tropical plants, this is the best time of the year to put in many woody plants.

One of the saddest things that can happen to a new gardener in Southern California is to go and look at other people’s glorious flower gardens in April and say “Wow! what are the names of these flowers? I want to dash to the nursery right now and buy them so I can have a garden like this one!” I have actually heard people say this, but unfortunately it doesn’t work that way here. Most of the flowers people gasp over at the height of bloom in April have usually been blooming for months. If you plant these in April they will cost a huge amount of money and die one month later. The glorious flower garden you are looking at in April might have come from a few packets of wildflower seeds that cost under ten dollars and were planted in October, which is now. My message to you is start now, in fall, to plant for your April garden. The colorful plants you put in now from plants and seeds will begin blooming in winter and continue blooming into June, in some cases all summer. So unless you’re hosting a wedding don’t plant for fall now, it’s too late. We’re almost at the end of fall and into winter. Plant now for winter and spring.

Many of the best fall-blooming plants we grow in California are not annuals we grow in pots or beds for only one season but are perennial plants, such as, for example, paperwhite narcissus and Grand Soleil d’Or, which can be planted now from bulbs and they will come back year-after-year. In your climate zone if you plant these now they will bloom in late winter or early spring, but after that they will come up every fall and bloom now. So they are among our best plants for fall and winter color when other things are not in bloom. Much of our fall color also comes from permanent plants. Two of the most colorful and splashy plants for color now are Mexican sage (Salvia leucantha) and Copper canyon daisy (Tagetes lemonii) but you would have needed to plant them month ago to have all that color now. Other fall-blooming plants of shrub size include euryops and Hypoestes aristata ‘Lavender Cloud’. These are all in full bloom now. Roses are magnificent in fall here also but don’t buy them now. Wait until the bare-root season in January. You might find some of the fall blooming permanent plants for sale now because nurseries usually carry plants only when they are in bloom. Get them while you can, but when you find these plants for sale they will be tiny— too small to make a splash. Plant them for the future. Salvia leucantha and Tagetes lemonii look great planted together, side by side in full sun and they bloom spring and fall. Give them plenty of space. They are big plants and should be cut back after bloom. Hypoestes would be a great addition to your garden in semi shade. It is difficult to find, but worth a hunt. It too is a large plant. I have a huge drift of it four foot tall and wide in full splendiferous bloom right now. It began with one spindly-looking plant in a gallon plan that I found in a nursery in late October or early November. If you find one, snaffle it up! This is a great plant for a narrow bed on the edge of a patio in part shade. I grow it on the west side of a pergola covered with wisteria so it blooms when the wisteria does not.

Please read the September, October, and November chapters in my book, “Pat Welsh’s Southern California Organic Gardening Month by Month”. These chapters will prove invaluable in your quest for a garden with color in fall as well as every other season of the year.

Related posts:

1. Chryanthemums: How to Grow Year-Round in mild-winter climates
2. Fragrant Plant in Southern California
3. Growing Lilac (Syringea vulgaris) in Southern California

Anyway, I am so looking forward to reading your book and exploring the site as I look for ways to add more practical, sustainable beauty to my Southern California yard. (That’s a fancy way of saying “stuff I can’t easily kill.”)

Thank you again for taking the time to help me with my poor misplaced Brazilian plants.

Answer from Pat:
Good luck with your garden and glad you got my book! Last night after writing you I had another thought. Sometimes when folks say, “I can’t grow such and such but there’s a lovely one across the street,” it’s all because of exposure. Usually the house where whatever plant it is grows fine faces east and the person who can’t grow the specific plant lives in the house across the street that faces west. West-facing is a difficult exposure for some plants because they are cool and comfortable all morning and then fry in the afternoon.

Related posts:

1. Princess Plants (Tibouchina heteromalla and Tibouchina urvilleana.)
2. Starting a New Business: Building Raised Beds for Growing Vegetables
3. Growing Lilac (Syringea vulgaris) in Southern California

Answer from Pat:
Heartwarming to hear how you love that old book but of course wish you’d try the new one. (Didn’t you ever notice that I omitted geraniums? By mistake of course.I wrote the section but it “fell off” the end of a document and never made it into that first book. So much for being a computer idiot at the time. A lot of other things didn’t get into to it either, including all the opening chapters (due to lack of space.) But after that first book’s huge success, I was able to put all the accidentally and on-purpose omitted stuff into the second edition published ten years later in 2000, and now the new edition (2010) has all that and more and is all-organic to boot. I’ve gone back to my roots on our Pennsylvania organic 1940′s farm and “tell all” about organic gardening and farming, how and why in the introductory chapter.

I know Hancock Park well. What a great place in which to live! One of my five grandchildren, Rebecca Woolf, blogger extraordinaire (http://www.girlsgonechild.net/2010/04/garden.html,) and her husband Hal and their kids Archer and Fable lived nearby, all squashed together in a little house in Larchmont, for five years, but now they have moved up in the world, to Hollywood, a month ago. I haven’t seen their house (still a rental) yet but intend to soon.

Now for your chain link fence. My younger daughter, Wendy, Rebecca’s mom, and husband Larry planted star jasmine (Trachelospermum jasminoides) and potato vine (Solanum jasminoides) on a fence between themselves and next door neighbors must be 25 years ago. It’s still there. If ever messy or a bit overgrown, they just chop away at it. It’s provided good privacy. I planted star jasmine, some in shade, some in sun here at my house on a fence. That was 1982. It’s still fine. We try to control width by shearing it after bloom. Works pretty well and gives me excellent privacy from the road below the bank. It’s not on chain link but similar since one could see through if no growth on it. The look is of a hedge, which I like, and also the flowers are so delightfully fragrant for a month or more. Other things I like for chain link fences are Thunbergia gregori, Bougainvillea x buttiana ‘Golden Glow’, Blue Sky Vine (Ipomoea indica) but problably not a good choice since it’s invasive—Nonetheless I love it—, and Pyrostegia venusta. Another thought is Lavender trumpet vine (Clytostoma callistegioides.) It’s such a splash of color and long spring and summer bloom and no pests or diseases, any kind of soil, and easy to control. Only problem: A bit slow to start.

One caveat on jasmine: Begin with plants that are already on trellis in 5 gallon cans. You should be able to get them right now since they are still in bloom. Set them in the ground so the trellises touch. This will give you a fast cover. There is no rule saying you have to have only one thing. You could plant a splash of color as well. A bougainvillea in the hottest spot for example. It wants full sun and hot hot spot to do it’s best. Since you have red clay soil, dig half a coffee can full of gypsum into the bottom of every planting hole to improve drainage. Gardens are great in Hancock Park. That nutritious clay soil can grow great roses and many other flowering plants. Re: thickness, shear to control after bloom. Let the neighbors worry about their side. Pyrostegia venusta drapes down like a curtain, not thick. Thick is nice since it’s private.

Longtime friend of mine, the late great Chuck Kline of Seaworld, once said to me, “If you want to grow something, try it. If it’s the wrong thing, change it! Don’t be afraid to yank things out and try something else.” So really you can’t go wrong. If I were you I’d do star jasmine and plant now.

Great idea about your formal potage. Have fun! (Sounds as if you are.)

Related posts:

1. Choosing a vine for dappled shade
2. Cutting back a Passion Vine (passiflora)
3. Planting with the Seasons (Indigo Salvia and Ageratum)

Answer from Pat:
I have not recently driven the road between Reading and Sacramento. However, here are some of the plants that have been introduced recently for highway planting and are often used for freeway median planting by Cal Trans:

Meilland disease-resistant and pest-resistant rose shrubs developed in France especially for highways include ‘Fire’ (red), ‘Ice’ (white), ‘Magic’ (hot pink), and ‘Pink’ (pastel pink). My guess is these are what your relative saw since I’ve seen them also and found them eye-catching. We are seeing ever more of these roses on highways and it’s a bit of a surprise since one doesn’t think of roses as being an easy plant and we also know roses need regular water. It turns out, however, that these varieties are easy to grow, don’t require a lot of special care, and are especially colorful and pleasing when ornamenting medians and banks on crowded highways near or in cities where large numbers of motorists can enjoy the sight.

Also often planted along freeways, especially in the Bay Area, is bright or deep royal blue plumbago auriculata. (I would guess the variety they are using is one of the improved varieties, like ‘Royal Cape’ or ‘Imperial Blue’. ) Plumbago blooms its head off for most of the year and is drought-resistant once established. I have noticed these plants near to towns and especially in the Bay Area. This is a tender plant that cannot be grown in Ohio unless it be in a house, conservatory or greenhouse.

For many years in warmer zones one has seen many miles of oleander (Nerium oleander) blooming for many months in freeway medians in warm zones but winter frost can hit it up north. Also there is a pest called the glassy-winged sharpshooter that has caused a lot of problems with oleanders. All parts of oleander are poisonous but that doesn’t matter in a median plant and its height (6 feet) and fragrance together with dense foliage of long green pointed leaves, make it a good, drought-resistant barrier plant. Special machines are used to hedge it after bloom. Oleander flowers massively spring through fall in shades of pink, white, and red.

Additionally, native plants such as blue California lilac (Ceonothus) are planted in some areas. In inland areas that get very hot and dry, Texas ranger (Leucophyllum frutescens) is one of the best and toughest plants. It provides long bloom on attractive grayish foliage in hot, dry, desert-like conditions and it’s hardy down to 12 degrees Fahrenheit. Another purple plant one often sees along highways is Lantana montevidensis. This also has lavender or purple flowers and is long blooming, drought-resistant, carefree, and easy to grow, but a hard frost will damage it.

Related posts:

1. Evergreen Trees for Median
2. Plants for Beachfront and Seaside Gardens in Southern California
3. Native Plants of the Southern California Coast