All nurseries will provide you with information when you purchase plants as to correct spacing of the plants you buy. Most plant labels have size and spacing listed on the label. Always ask the correct spacing of plants at purchase time. If you failed to do this, you can find information on spacing in paperback books on landscaping and ground covers, and on the internet. As a general rule, it is not an appropriate use of my time to be providing it since there are so many thousands of different plants that we grow here, and each have different spacing. Nonetheless, since you wrote to me, I will provide it this time, but I would like to help you find this sort of information for yourself. For example, if you had simply Googled “Correct spacing for Bougainvillea ‘La Jolla’ “you would instantly have gotten the information: 6 to 8 feet apart. Now it’s time to use your head. Ask yourself: “Am I going to plant in drifts for an all-over look? Or am I going to dot these plants on the hill with the ground cover between them?” These kinds of thoughts in your head will help you to come up with sensible answers: For example, you might decide to put the plants further apart—as much as 15 feet apart if other plants such as plumbago and lantana are going between them.

Here is an example for how to find out correct spacing of all garden plants. Look at the label of your plant. It may provide spacing. Most plant labels do. Or it may provide mature size. Or to find out the mature size, if the label fails to say, look up the eventual size of the plant up in Sunset Western Garden Book, a plant encyclopedia every gardener needs. (My book does a different job. My book tells you when to do what and how to do it.) Sunset is a complete encyclopedia, an alphabetical list of almost every garden plant we grow in the West. It provides correct spacing for many plants or when not providing spacing it provides mature size. My book does not try to replicate this, that would be senseless. My book belongs side-by-side with the Sunset Western Garden Book and the two books work together, Sunset naming and describing the plants, and mine telling you what to do when.)

(Also in Sunset, there are some informative pages in the back on basic information. Please read page 726 How to Plant Shrubs and page 691 How to Plant Groundcovers. Also look at the index on page 764 for other planting guidance that might help you.)

Now here’s how to use Sunset to find out correct spacing when it is not provided: In the latest edition of Sunset Western Garden Book on page 552 (the most recent edition), it describes the mature size of Plumbago auriculata as making a mound 6 feet tall and 8—10 feet wide. Plant the specimens so they are exactly the same size apart as the eventual mature size of the plant, that is 8 to 10 feet apart. This is fine also for ‘Royal Cape’ or ‘Imperial Blue’, whichever one you purchased. (You mentioned ‘Royal Robe’, but I think you said that by mistake. ‘Royal Robe’ is the name of the best Solanum rantonettii, another lovely plant but it is 6 to 8 feet tall and wide and looks best with more water, so not as good on this bank.)

Find the spacing for all your other plants in the same way as I have described above. The correct spacing for every ground cover should be provided on the plant label or provided by the nursery if you phone them, but for many 6 to 8 inches apart is about right. Some shrubby plants should be place 12 inches apart. It all depends on the mature size of whatever you are planting and the way a plant grows whether creeping or not. Take the mature width of the plant and you then have the correct spacing, or for a quick cover you can put them a little closer.

Yes, you can purchase lantana in flats and if you do, then plant them closer together. But the variety of lantana that is most frequently available in flats is a species called Lantana montevidensis, which is a purple, trailing lantana, not the same color as ‘Radiation’, which is a whole color scheme in one plant and is a more shrubby type. When planting lantana from small plants from a flat, put them closer together, —about one foot apart— than you would if planting from one-gallon or five- gallon size.

Regarding the ivy (probably Algerian ivy) it would be best to cut it off and keep it cut off and pulled out on your side of the fence. This is what I do in one part of my property where a old bank of ivy is separated by a flight of steps made of concrete sacks from the rest of the garden. We just keep policing and cutting it off and pulling it out and this way have successfully controlled it for many years. You can plant right over the ivy if you want, but unfortunately it will eventually climb up and cover over some of your plants, spoiling their appearance. It will, however, help hold the bank.

Yes, birds will be attracted to these plants, but you didn’t mention until now that attracting birds was a priority. Had you done so I would have suggested an entirely different group of plants. However, hummingbirds will visit the plumbago and lantana flowers. Butterflies will visit both of them, but for lists of plants especially attractive to birds (and other pages of plants attractive to butterflies, and many other specialized lists), please see the book I wrote called “The American Horticultural Society Southwest Smart Garden™ Regional Guide.” I wrote this book of lists to help gardeners such as you choose plants according to where you are going to plant them and how you will use them. Plants that are especially attractive to birds are listed, described, discussed, and pictured on pages 132, 133, 134, 135, 208, 209, 210, 211, 242, 243, 298, and 299. (Also see the list of all the lists contained in the book on page 82.) In my copy I have written the page numbers on every page, since many page numbers were omitted by the publisher, D.K. This is a beautifully designed book, but the publisher D.K. had the crazy idea that page numbers on every page would screw up their pretty design, so they would not listen to me when I told them there should be a page number on every page. Reference books need page numbers, and this is a reference book, not just a coffee table book.

Related posts:

1. How to Space Plants when Planting a Bank
2. Formal Garden and Informal Plants
3. Where to Find Photos of Pat’s Garden

From Kathy:

I thought maybe two bushes on the bottom in the slide area one aon  the top part of the easement on the bottom slope  and then put another one further down toward the street.  How many do you think I need for the upper part?

Answer from Pat:
To space plants properly, first measure the space, then look up the plants in Sunset Western Garden Book, or in paperback books on ground covers, or ask your nursery. Every plant has appropriate guidelines for spacing. (ie, how many feet or inches apart the plant needs to go.) Some landscapers put plants much too close together for quick effect.This is a bad idea since after a year or two the homeowner is always needing to cut back. You can figure out how far plants need to be put apart from each other, simply by knowing the eventual size of the plant, and doing a plot plan so each plant fills that amount of space and the edges touch. For small groundcovers. make a triangle of cardboard, each side being the distance apart. Use it for placing plants at appropriate distance from each other in a triangular, diagonal pattern.

Related posts:

1. Planting a Bank
2. Planting on a Bank & Best Substitutes for Lawns
3. Correcting Erosion on a Steep Bank in Encino

Question from Howard:

Answer from Pat:
Before I can answer your question, I need to know where you live. Plants are adapted to certain regions and not to others. I cannot give you any suggestions for what to plant without knowing where you live. For example, what if you live in the Middle West, or Arizona, or New England? Your question gives me no clue. My recommendations for planting a bank in each of these regions would be totally different. Also, if you live in Southern California, or anywhere in the west, please tell me what Sunset Climate Zone you live in. (Please do not give me the USDA Climate Zone since they are not specific enough.) If you give me your Sunset Climate Zone, I will know what plants to recommend. Also, please refer to my suggestions to other readers who have written with questions about planting a bank. Perhaps I have already described a bank planting that will perfectly fill your needs. You will find many suggestions included in the answers given on the following link: Plant to Prevent Erosion on a Steep Hillside.

Related posts:

1. Planting a Bank
2. Planting & Growing Zone
3. How to Space Plants when Planting a Bank

Question from Kathy:

I have a new problem and do not know what to do. I live on top of a steep hillside and have been here for 34 yrs. I have never had a mudslide. However, the hillside is in three levels and the bottom one had a some mudslide last winter. It was covered with the old heavy ice plant and the woman who lives across the street from my hill started pulling it out and planted red apple and some nasturtiums as she didn’t like the weeds in between the ice plant. Now I need to know how to fix this problem.

What is the best and toughest ground cover ?

I live in Rancho Palos Verdes. The slide is about 3 feet deep by about 4′ wide at the top and a narrow 9′ down to the street . It has thick red apple on one side and scattered old ice plant on the other side. Thank you so much

Answer from Pat:
Thanks for kind comment. Below are a lot of ways to fix a steep bank. I think I was considering a larger space than you actually have, but I have given you so much to chose from you can make it fit your needs. Also this advice may help others who read this site.

As you undoubtedly know landslides on the Palos Verdes Peninsula can be a serious matter since they might signal a problem with an entire strata of wet adobe soil slipping down over a harder layer of soil below. This kind of slide can happen when the “tow” of a hillside has been unwisely bulldozed or cut into. It might be wise for you to contact your UC Extension Home Horticultural Advisor, Department of Agriculture, or your local city officials before trying to do anything to correct the slide so you can first make sure there is no serious slippage problem in this case. In many cases in the past mudslides have endangered houses or even lives, though yours sounds smaller in scope than were those.

Once you have determined that this is not a widespread or potentially dangerous situation, then you can undertake some steps to try to correct the problem. First, ice plant is seldom a good solution for a very steep bank, since it can actually pull a bank down by its own weight. Nonetheless if it is growing there already and holding a bank it’s unwise to pull it out as your neighbor did since this can make the whole bank slide as happened in this case. A wiser way to make a change is to cut the ice plant short and leave the roots in place, then plant right through it. The roots will continue to hold the bank while the new plants take over. It’s too bad your neighbor didn’t know of this old-timers trick, a common practice in California gardens fifty or sixty years ago when people with new homes covered banks with ice plant quickly to hold them through winter rain then soon upgraded to something better.

Also, red apple ice plant is not a very good solution for steep banks since it needs a lot of water and calcium nitrate fertilizer to stay green. It’s far better to plant something more environmentally responsible. When trying to plant a bank for the purpose of stabilizing slipping soil, the very best way is to plant a mix of deeper- rooted larger plants along with shorter-rooted ground covers to cover the ground between them to hold the ground as the larger plants are getting going. Examples of shorter rooted ground covers are gazania or arctotis. Then you could dot such plants as shrubby bougainvilleas all over the bank, along with something like ceonothus ‘Concha’. I recommend bougainvilleas as one of the better plants for such an area. They will grow on a drip system and grab deeply into the soil. Once fully established they become very drought-resistant and you get a lot of bang for the buck. Another fairly deep-rooted bank cover plant is Acacia redolens ‘Desert Carpet’ or ‘Low Boy’. This too is very drought-resistant once established. Lantana montevidensis is hugely colorful with lavender flowers almost year round and also very drought-resistant, easy to grow and good on banks. Finally consider blue plumbago. For a gang busters combination on a bank and drought-resistant year-round color, plan yellow trailing gazanias to cover the ground, then use an equal number of the the following plants to send down deep roots and hold the soil: Bougainvillea ‘La Jolla’, Plumbago ‘Royal Robe’, and Lantana ‘Radiation’.

Another way to go and perhaps more exciting, but best planted in November: You could do the whole thing with native plants. You might try toyon or Calfornia holly (Heteromeles arbutifolia ) at the bottom of the slope. (Get the one from Catalina that has bigger berries.) For a native shrub requiring no water whatsoever in summer, plant flannel bush (Fremontedendron ‘California Glory’.) Or, for a compact one, try F. ‘Dara’s Gold’. Plant this next to ceonothus for a great color combination blooming at the same time in spring. I think natives are probably the way to go with this slope but you could get a ground cover going first to hold everything until fall. Matilija poppy (Romneya coulteri) is a great way to grab a bank but not a good time to plant now. I planted three of these last November and they are all growing and blooming. All natives are best planted in November but it would be all right to cover the bank now with some native ground covers though perhaps not California perfume (Ribes viburnifolium)—great on banks but might not survive planting now. But bear berry (Arctostaphylos urva-ursi) or coyote bush (Bacharis pilularis) I think might mostly survive along the coast even if planted now since we’re having cooler than usual weather, and then plant the bigger things in fall.

Related posts:

1. Erosion Control for Steep Hillside: Last Minute Installation to Hold the Soil
2. Correcting Erosion on a Steep Bank in Encino
3. Native Plants for Erosion Control on Steep Banks

• Adenostoma fasciculatum—Chamise
• Most abundant shrub in some local coastal chaparral, often called “Chamise chaparral”. Known for spring bloom but often flowers in fall.
• Arctostaphylos glandulosa, ssp. crassifolia—Del Mar manzanita
• Coastal manzanita endemic to local region.
• Arctostaphylos pumila—Sandmat manzanita
• Arctostaphylos uva-ursa—kinnikinnick
• From northern California but will grow here.
• Artemisia californica—California sagebrush888
• Frequently found in old coastal stands of chapparal
• Artemisia pycnocephala—Sandhill sagebrush
• Grows in Torrey Pines Park
• Atriplex canescens—Fourwing saltbush, Cenizo
• Mounding to 8 feet, can take irrigation but thrives with none, all parts edible by humans or birds. Attracts birds and butterflies.
• Atriplex lentiformis ssp. breweri—Brewers saltbush, Quail bush. Foliage and seeds are edible. Brings birds. Grows to 8 feet.
• Baccharis pilularis—Coyote brush
• Not exactly trouble free since, in a solid planting, some will die probably from root rot. Old stands can be renewed by mowing to the ground in fall.
• Ceanothus gloriosus—Point Reyes ceanothus
• Ceanothus griseus (not including ‘Diamond Heights’)—Carmel ceanothus
• Ceanothus maritimus—Maritime ceanothus
• Ceanothus thyrsiflorus—Blue blossom ceanothus
• Ceonothus verrucosus—Warty-stem ceonothus
• The kind that grows in Torrey Pines Park
• Cercucarpus betuloides—Mountain mahogany
• Coreopsis gigantea—Giant coreopsis***
• Usually dies if irrigated in summer. Needs full sun.
• Dendromecon rigida—Bush poppy***
• Eyecatching bloom on clean shrub with attractive foliage.
• Encelia californica—California sunflower***
• Likes underground water such as in a canyon but will live without. Best in sun but can take partial shade.
• Eriodictyon crassifolium var. crassifolium—Thick leaved Yerba Santa***
• Many healing uses for Native Americans, colorful lavender flowers in late spring; soft, felty textural leaves.
• Eriogonum arborescens—Santa Cruz Island buckwheat***
• Excellent garden plant, thrives with no water or can take some irrigation.
• Eriogonum cinereum—Ashyleaf buckwheat
• Grows in Torrey Pines Park
• Eriogonum fasciculatum ‘Dana Point’—Dana Point buckwheat***
• Improved form of frequent component of coastal San Diego chaparral. Available: El Nativo Growers, Tree of Life, others
• Eriogonum parvifolium—Bluff buckwheat
• Often grows closest to ocean front on bluffs at Torrey pines.
• Eriogonum giganteum—Saint Catherine’s lace***
• Stunning plant from Catalina Island. Grows well in San Diego coastal region. No summer water needed.
• Eriogonum grande var.rubescens—Red-Flowered buckwheat**
• Striking member of the buckwheat family from the Channel Islands.
• Eriogonum latifolium—Coast buckwheat
• Grows in Torrey Pines Park and around many local lagoons
• Eriophyllum nevinii ‘Canyon Silver’—Canyon Silver island snowflake
• Fremontodendron californicum ssp. californicum—Fremontia, Flannelbush
• Not found growing wild along the coast but can adapt to steep coastal banks if planted there. Worth a try for its extreme beauty next to blue ceonothus on a steep slope. Needs some water to become established. No summer irrigation once extablished.
• Heteromeles arbutifolia—Toyon**
• White flowers in spring followed by colorful red berries in fall and winter bringing birds. Some selections have larger bunches of berries. Abundant in local coastal canyons.
• Isocoma menziesii var. menziesii—Coastal goldenbush, Menzies goldenbush***
• Common along the coast, abundant flowers in late summer.
• Tree of Life Nursery, San Juan Capistrano, 92693
• Isomeris arborea—Bladderpod
• Found in Torrey Pines Park and around local lagoons
• Lavatera assurgentiflora—Island shrub mallow**
• Evergreen shrub, to six feet, long flower season, very salt tolerant, from Channel Islands, has naturalized in some mainland areas.
• Lepechinia calycina ‘Rocky Point—Rocky Point pitcher sage**
• Brings butterflies. El Nativo growers has this compact (to 3 feet)selection. Good coastal plant.
• Lupinus arboreus—Bush lupine***
• Grows well along the coast. Self seeds. (Las Pilitas Nursery)
• Malacothamnus fasciculatus, (syn.: M. arcuatus) ‘Edgewood’—Bush mallow, Coastal bushmallow***
• Improved form of delightful shrub with flowers over long season, almost year round if irrigated. Often sprouts on disturbed land and the wild unimproved form is currently seen growing adjacent to Penasquitos Lagoon. Some sources say it does not live long unless cut to the ground annually in fall. Detests hot interior climates, but thrives near the ocean. Makes a very good bank cover Can be seen on Leucadia Blvd where the road cuts through the golf course. This steep irrigated, planting blooms almost year round and none of these examples have either been cut back or died since they were planted about 5 years ago. May attract ground squirrels, rabbits, caterpillars and grasshoppers.
• Malosma laurina (Rhus laurina)—Laurel sumac
• Big shrub or small tree. Las Pilitas
• Mimulus aurantiacus—Bush monkeyflower
• Yellow, white or orange, shrub or subshrub, widely adapted and very colorful with many improved hybrids. Grows well along the coast. Common in Torrey Pines Park and on north-facing hillsides.
• Myrica californica—Pacific wax myrtle
• Shrub or tree to 15 feet, best along the coast. Las Pilitas.
• Rhamnus croceas—Redberry; Spiney redberry.
• Brings birds and butterflies, good barrier plant. Needs no water once established. Tidy looking evergreen shrub, flat to 2 feet mounding. Las Pilitas Nursery.
• Rhamnus californica ‘Eve Base’—Coffeeberry
• More compact form of large, 8-foot chapparal shrub; this one grows to about 5 feet. Looks shaped without clipping. No irrigation needed, once established. (Las Pilitas Nursery.)
• Rhus integrifolia—Lemonade berry***
• Among the best-looking, easiest-to-grow, evergreen shrubs native to the San Diego coastal area. Found all around San Elijo Lagoon and most other lagoons. Good road edge and screen in gardens. Can be grown in full sun or light shade, with or without irrigation. Amenable to clipping, shearing, and training. May succumb to root rot if grown in heavy soil and irrigated too much in summer.
• Salvia leucophylla—Purple sage**
• Grows wild in Torrey Pines Park. Large sprawling groundcover, well adapted to coast. Las Pilitas.
• Salvia mellifera—Black sage
• Most abundant sage in Torrey Pines Park. 3 feet tall. Las Pilitas
• Suaeda taxifolia—Woolly sea-blight
• Common to salt marshes, can be grown where the ground floods. Las Pilitas
• Trichostema lanatum—Woolly bluecurls**
• Common at low elevations, less common around lagoons but worth a try for its lovely blue flowers.

PERENNIALS

• Achillea millefolium—Yarrow**
• Frequent member of our coastal plant community
• Aster chilensis ‘Point Saint George’—Point Saint George aster**
• Improved selection of a similar aster species to the species of aster found growing in coastal San Diego.
• Aster subulatus var. ligulatus—Slim aster
• Grows near coastal lagoons, such as Buena Vista
• Coreopsis maritima—Sea dahlia***
• Cannot take summer irrigation. Needs full sun.
• Dryopteris arguta—Coastal wood fern
• Needs shade,
• Erigeron glaucus—Seaside daisy**
• Eriophyllum confertiflorum var. confertiflorum—Golden yarrow**8
• Gnaphalium californicum–California everlasting**
• Fragrant blooms over a long period in spring into summer.
• Lotus scoparius, var. scoparius—Coastal deerweed***
• Lotus brevarius grows inland after fires. L. scoparius is abundant near San Elijo and other lagoons and along coastal roads. Long bloom season spring and summer. Short lived but fixes nitrogen in soil. Las Pilitas
• Sidalcea malviflora—Checkerbloom**
• Tanacetum—Dune tansy**

ANNUALS

• Abronia umbellate ssp. umbellate—Sand verbena
• Prostrate and spreading with purple flowers in spring and summer common in sandy coastal clearings.
• Camissonia bistorta—Calfornia sun cup
• One of the more easily identified yellow spring wildflowers common in sandy soil near coast.
• Cryptantha intermedia—Popcorn flower
• Coastal wildflower with bunches of white flowers on hairy plant in
• Spring.
• Layia platyglossa—Tidy tips
• Seen in spring on Torrey Pines bluffs
• Lessingia filaginifolia var. filaginifolia—California aster
• Native to coastal San Diego***
• Lasthenia californica—Goldfields***
• Common on Torrey Pines bluffs
• Linanthus dianthiflorus—Ground pink
• Colorful, abundant after good rains, low stature.
• Pluchea odorata—Fragrant march fleabane
• Found near lagoons and marshes, pink flowers in summer and fall. Frangrant gray foliage.
• Stephanomeria diegensis—San Diego wreath plant
• Little purplish-white flowers on wirey plant have some resemblence to babies breath, common summer wildflower near the coast.

GRASSES

• Not listing any grasses due to invasive qualities.

SUCCULENTS

• Agave shawii—Shaw agave***
• Excellent barrier plant with clean appearance, bold, architectural shape and ferocious spines. Uniquely-shaped bloom spike is attractive to hummingbirds.
• Cylindropuntia prolifera—Coast cholla**
• Extremely prickly plant for keeping out intruders, not for use near paths.
• Opuntia littoralis; O. orricula—Coast prickley pear**
• Effective spiney barrier plant for use away from paths. Used on banks will keep out intruders entering from above or around gates.
• Dudleyas—Any of the types listed on the green roof list would adapt to being grown on the ground, but could easily be damaged by foot traffic.

Related posts:

1. Native Perennials Suitable For Planting Near A Coastal Lagoon
2. Native Annuals Suitable For Planting Near A Coastal Lagoon
3. Native Shrubs Suitable For Planting Near A Coastal Lagoon

Feed camellias and azaleas now.

Related posts:

1. When To Plant Annual, Perennial, and Biennial Flowers From Seeds
2. Starting Seeds
3. Storing and keeping seeds

Question from Robin:

I spread granulated sulfur on the top of heavy clay soil. Hindsight shows me this is not optimum, and I would like your opinion on my options. I want to establish vegetables on the site. And I had wanted to do it ASAP.

The garden is 10 x 15 feet and I spread most of a 5 lb box of sulfur “lentils.”

The following is a list of options I have thought through. I would like your opinion and suggestions.

Scrape it off and start over. (e.g. Amend with gypsum and compost.) -Removal poses safety and disposal problems. I would need advice on the best way to go about this

Till it in

• I worry that this might throw sulfur out of the garden area, endangering the dogs. (I’ve never used a tiller) I burned my hand on the dust so I’m a bit nervous.
• It will burn any earthworms under there.
• It may burn the roots of garden plants

Till it in, cover with 6” Agromend, and plant my veggies.

• any chance I can get away with this? It will still probably kill earthworms, but would the plants survive?

Scrape it off, save it, till the soil and apply properly at appropriate depth. After tilling in the sulfur, cover with 6” agromend and plant veggies.

• I feel this would be the best way if I want to grow veggies this summer, but I wouldn’t know what to save it in. Again I would need some safety advice.

The most sensible and least desirable option that I have come up with:

• Till it in, leave it till fall or next year, then establish my garden.  I’m unemployed and this was my chance to make a break from the office retrace. I want to sell at farmer’s markets to get myself known, and eventually open a nursery. This is a long time dream. I don’t want to go back to an office.

Corollary question:

Green humb carries an adorable garden boot, but will I need industrial type chemical resistant boots if I walk in this stuff? I haven’t yet stepped into the garden.

Answer from Pat:
As explained below, I don’t advocate that gardeners use soil sulfur but despite that, a five-pound box of granulated sulfur spread over a space that is ten by fifteen feet in size and then dug into the ground is not going to do any huge amount of harm. The correct proportion of soil sulfur to garden soil (if one were to add it) is 5 pounds for 1,000 square feet twice a year. (This is supposed to bring down the base of calcium in the soil and raise magnesium.) It would do more harm to the environment for you to scrape it off and dump it. I doubt also that it is going to kill earthworms since you are digging it into soil that I presume you already know is alkaline. Add plenty of organic matter into the ground and as mulch on top and you’ll get any number of earthworms. Also, once you have combined the sulfur with the soil, the alkalinity in the soil will neutralize the acid in the sulfur. That is a backwards way of saying the whole point of adding soil sulfur is to create a less alkaline condition in the soil. Your best option since you’ve already spread the sulfur is to dig it into the top foot or more of the ground. It will gradually combine with the soil over the years as you dig and amend your garden soil with organic matter twice a year prior to seasonal planting spring and fall. You could, however, rake it up and dig it into the ground in another part of the garden where you are not planning to plant seeds, but I really don’t think this is necessary.

You mention that you don’t use a tiller but amending the soil includes first spreading on the amendments and then using a garden fork or a garden spade and turning the soil over to combine ingredients into it. One does not need a tiller to do this, one just needs a sharp spade or garden fork and strength like I once had and don’t have any longer. Or you need a willing workman to do the job for you. Either that or become a “No Dig” gardener, but in that case never use anything like soil sulfur that has to be combined with soil in order to work.

Companies make granulated sulfur because it is considered safer for the environment than liquid sulfur which is a by product of some industries. Soil sulfur is a mined product, a natural mined element that comes from the earth. Sulfur is acid, not alkaline, and sometimes farmers add it to soil to try to correct problems with alkalinity. Soil sulfur differs from dusting sulfur. Dusting sulfur is one of the most ancient garden products. It has been used by mankind for thousands of years for dusting onto plants to kill some insects and plant diseases, such as mildew and blight. (American Indians dusted sulfur onto plants long before the white man discovered the New World.) Soil sulfur is sold by some nurseries as an acidifier for alkaline soils.

Despite all this, I do not advocate the use of soil sulfur by the home gardener for the purpose of acidifying soil. Instead, I have always felt the best way to acidify garden soil when necessary is to work in acid organic soil amendments, such as wood shavings. The main reason that I don’t recommend the use of soil sulfur for soil acidification is not so much because it’s dangerous, but more because it doesn’t work. In order to have soil sulfur work one would have to work it into the soil so that it is evenly distributed and so each grain of sulfur actually contacts individual particles of alkaline soil and then it also takes time to work, so you would have to keep it up twice a year. For example, simply spreading sulfur on top of the ground around camellias and azaleas and hydrangeas and then watering it in, as some gardeners have done, won’t work because sulfur doesn’t water into the ground that way.

You should also be careful not to breath sulfur into your lungs and you should use protected clothing, including gloves, when handling it. Also, soil sulfur can sometimes inhibit seeds from sprouting rather like corn gluten meal does but this action won’t last forever. It’s temporary.

Please refer to the pages at the beginning of my book for ways to treat alkaline soil, such as clay and for ways in which you can improve clay soil and make it drain better. Yes, gypsum is a harmless and helpful addition if your clay soil is compacted due to its alkalinity. (Please refer to other discussions about gypsum on this site.) Also, there is no better way to make clay soil drain than mixing in a layer of well-composted organic matter and keeping it up throughout the years.

Related posts:

1. Soil And How To Fix It
2. Plant Zinnias Seeds
3. Growing Healthy Blackberries

Question from Randy:

What is the best medium to plant epidendrums in? Cymbidium bark, soil or a mix. Thanks. Or none of those?

Answer from Pat:
Epidendrum orchids grow well in ground bark or small gauge pathway bark. I don’t ever purchase orchid bark since it is the same thing as pathway bark, but more expensive and often mildewed. In interior zones, I recommend mixing pathway bark with about 1/3 Super Soil to create a more water-retentive mix so that one does not need to water as frequently. I have also seen big tubs of epidendrums growing successfully in potting soil. In a garden in Rincon, California I once I saw a 20-foot-long, brick-walled raised bed flanking a swimming pool. The bed faced south and was filled with epidendrums in full bloom growing in sandy top soil.

This garden was near the beach.

Related posts:

1. Right Mulch for Beach Plants

Question from Shannon:

Answer from Pat:
See pages 69 and 399 in my book for advice on this plant. Main things all Tibouchinas need are acid soil and constant moisture with good drainage. I thought Tibouchina heteromalla were going to be easier to grow. Most people thought so. Many people purchased them, but they seem short lived. They are definitely not good in containers, they need to be in the ground in rich acid soil with good drainage, constant moisture, and regular organic fertilizer. (Think Hawaii!) Also the cold nights we have had this summer can take its toll on tropicals. I note several I had admired in gardens on my walks while I was writing my book were lovely for a couple or three years. Now all have died—Ooops!—I tried growing Princess tree (Tibouchina urvilleana) in a large tub. No go! I tried it in the ground, in a hole filled with acid soil mix, planting it just like a camellia. (That’s what you have to do.) But my sandy soil and some invasive roots nearby meant curtains for this lovely specimen. I would have needed to leave water running all the time, night and day, for it to survive. We need to face up to the fact that all Tibouchinas are rainforest plants.

Yes, I adore these plants too. You just have to love that vivid purple bloom color and against those soft velvety leaves. Best Tibouchina urvilleana I have ever seen? (I drove by them today as I do almost every day en route to the post office.) They are at least 6 years old, planted next to a lawn, facing north, acid soil, fed constantly, and now in solid bloom, but—oh dear—today they were not looking as good as they used too. Still had a huge number of flowers, but fewer leaves than usual. What is happening? I fear one has died. So there you go! The folks who own that garden have gardeners who are in attendance 2 or 3 days a week and evidently the owners could care less how much money they spend on water or whether we really should be cutting back on watering and going for a more drought-resistant look than what they like, which good old tropical. Across the street from them is a very large and attractively planted drought-resistant garden with excellent design and plant choice. But they own that house also, so I guess they are going for two different looks, wet and tropical on one side of the street, dry on the other.

Related posts:

1. Exposure as a factor when growing Tibouchina
2. Patio Plants For Sun And Warmth
3. October-Blooming Plants for an October Wedding

Question:

Thanks again so much, and a very productive Spring season to you!

Answer: Tests have been done by the University of California and other entities to see if the idea that one plant, such as basil, for example, can effect the growth or flavor of another plant growing next to it, such as tomatoes, for example and it is impossible to prove any such relationship. Despite this fact and many tests done to try to see if companion planting works, gardeners and even some farmers believe that companion planting works. There are whole books on the subject.

In my opinion, as I stated last night, the reason that many gardeners think companion planting works is that growing many different plants mixed up together has the beneficial effect of cutting down on pests and diseases. This is due to the fact that pests like to concentrate and will come in greater numbers if they find a lot of what they prefer eating concentrated in one place. To some extent the same can be said for plant diseases. They build up in soil unless crops are rotated. Plant chemistry is complicated to the extreme and all the smells and colors of plants when mixed together can muddle up the pests. Some gardeners think caterpillars may be less likely to find basil if it’s alternated with tomatoes than when it’s planted in a solid row. (I tried this once but it didn’t work for me.) Lots of gardeners think it’s good to plant garlic here and there because it smells strong and pests leave it alone. These are not scientific statements and no one could prove them scientifically, but on the other hand it is a true and accepted fact that if one plant is grown in a field exclusively with no other plants mixed in, that plant will be more subject to pests and diseases than plants grown in a mixed environment.

Some interesting experiments, also have been done by the University of California and in England, with strip farming where a cover crop or a hedgerow is grown between areas of an agricultural crops. The practice of strip farming has been shown to help cut down on disease and also on pests because beneficials lived in the cover crop and later when it was dug into the ground as green manure there was a beneficial reduction of plant diseases that can build up in the soil. In the case of hedgerows in England birds and beneficial insects, including bees, live in the hedgerows and help with pollination or with protecting agricultural crops from pest insects when these crops have not been sprayed with pesticides. Crops are not as healthy in places where hedgerows have been destroyed, so there is a strong movement in favor of keeping the ancient hedgerows, not just for beauty’s sake but for wise farming and gardening too.

Last night when I said that companion planting has been proved not to work in scientific experiments done under the auspices of the University of California, I fully expected a storm of controversy. I am glad you spoke up thus giving me a chance to provide more information. Many times unscientific things seem to work and sometimes it turns out to be for the wrong reason. As I stated last night I’ve always planted flowers in and around my vegetables, not only for beauty but to muddle up the pests and this works.

Related posts:

1. Planting Summer Crops
2. Choosing and Planting Winter Crops
3. Crop Rotation