Flowering Subtropical Street Trees

A list of trees for use on a group of parallel streets in a 30-year old development. This was a gated condominium development with a block of ten parallel streets, each street being about 2 blocks in length. All the existing street trees had been ordinary green trees of inferior varieties put in by the original developer. Eventually they became diseased and needed replacement.

We chose to replace the diseased trees with subtropical flowering trees of small to medium size. This added excitement to the landscape.  These trees were also far more appropriate to the scale of the housing. Our plan was that residents of each street would meet at a party and vote among themselves to choose one tree species for their street. Every street was to choose a different tree, so the first groups to meet and decide got the greater choice. Thus there resulted a rainbow of colors as one drove from block to block.

(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. Purchase specimens that have been 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 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.