What is a tree, and what is a shrub? It’s impossible to draw an arbitrary line separating the two because some species fall into both classifications.
Loosely, a shrub is a woody plant with three or more stems eventually growing to a height of not more than 10’ feet—some say 8’ feet.
A tree has a single stem not less than 2” inches in diameter and a more or less spreading crown. It should grow at least 15’ feet tall.
Our common dogwood, for example, is usually considered a tree, but it can be handled as a large shrub with several stems.
On the other hand, winter huckleberry is often a twiggy shrub, yet I have seen specimens 20 feet high.
Cultivated Exotic Trees Finally Gaining Attention
Many exotic trees were cultivated long before native plants began receiving their attention, but I will only consider American flowering trees here.
Even this covers a wide range, so I shall again limit myself to those of low-growing form.
Shadblows should hold a warm spot in the heart of everyone, for they give us our first promise of spring.
Seeing their feathery whiteness among wintry-looking trees is always a delightful surprise.
Amelanchier Species
Many species are found in the eastern states, but Amelanchier Canadensis is the most widely distributed and the largest, sometimes growing 50’ feet high.
The tree is spreading and graceful with smooth, beautifully dappled bark.
Curving racemes of delicate white flowers appear with the unfolding leaves about the last of February in Louisiana and stay until mid-March. Moving northward, of course, it flowers later.
Amelanchier laevis is not as tall as Amelanchier canadensis but is more spreading and even more beautiful.
The flowers are larger and showier, and the fruit larger and edible. In both species, the leaves become lemon yellow in autumn with just a touch of light red where the sun strikes them.
In their native habitat, they grow in open spots on wooded hillsides.
In the deep South, they must have partial shade, but farther north, they probably can take full sun.
Both like rich, loamy soil with good drainage. Under cultivation, the shadblows begin flowering when not more than 6’ or 8’ feet high.
A few nurseries list the shadblows, but all should carry them.
Prunus “Plum” Species
In the spring, wild plums run the shadblows in a close race for first place.
Prunus mexicana, a southern species, is probably the earliest to bloom and certainly one of the finest.
The inch-wide flowers are borne in loose clusters on long pedicels, giving a lovely tiring effect.
A 20-foot, spreading tree in full bloom is an unforgettable sight. The big, red-purple fruit ripens in the fall and is edible.
A similar plum is Prunus Americana, which is more widely distributed but not quite so handsome.
Both like rich, light soil on well-drained slopes. They are also suckers to some extent but not enough to become a nuisance.
Another attractive species, Prunus munsoniana, is much worse in this respect and should be planted only on large grounds.
It has masses of small snowy flowers in early spring and clusters of shiny red fruits in mid-summer.
It prefers heavy, rich soil. Chickasaw plum, Prunus Angustifolia, and suckers, the worst of all, soon forming thickets.
The red and yellow fruits are sweet and juicy, but the flowers are rather inconspicuous. This should never be planted where space is a factor.
One of the most charming plums is Prunus umbellata. The trees are low and beautifully rounded in the open with slender drooping branches.
It blooms a little later than the Mexican plum and has tight clusters of small flowers appearing in snowy masses.
From midsummer to fall, the twigs droop with the weight of small, bright fruits which range in color from deep pink to blue-black.
It prefers loose, well-drained soil and never suckers. This beautiful species is rarely seen in cultivation—nor catalogs.
The Redbud “Judas Tree”
All of this whiteness offers the perfect foil for the brilliant color of the redbud or Judas tree, Cercis canadensis.
This low-growing tree blooms with the shadblows and wild plums and is truly spectacular when seen at its best.
The unusual color will tolerate no competition, and it should never be planted near shrubs that hold bright red fruits until early spring.
A breath-taking effect may be obtained on large grounds by massing redbuds where they will be seen through a frame of bare branches of taller deciduous trees
One or two nurseries offer Cercis canadensis alba, which is exquisite in its purity. All redheads ask for riches! heavy soil, which is either mildly acidic or neutral.
Crabapples
Why our native crabapples are seldom seen in cultivation is another horticultural mystery since ours lack only the bright red fruits seen on some of the Asiatic species.
Malus angustifolia is the most widely distributed species and shows great variation.
It is a low, wide-crowned tree with relatively narrow leaves and masses of shell pink, very fragrant flowers.
The greenish fruit is small and hangs in clusters. Malus coronaria, an eastern species, is probably the most handsome.
The drooping flowers are often 2” inches in diameter and have prominent golden anthers.
The tree is large, eventually reaching a height of 25’ feet, and seldom flowers until 10’ feet tall.
The prairie crab, Malus ioensis, occurs in several varieties and is my first crabapple to bloom, coming in early March.
It is a low tree, and the flowers are 6’ feet tall. The large, almost white flowers cover the plant and form a charming picture combined with the pink buds.
Oddly enough, the last to bloom is Malus ioensis Palmeri, a larger tree with almost white flowers blooming 2 months later.
All our native crabapples possess a unique and distractingly sweet perfume. They are easy to please as to soil but prefer to be on the heavy side.
Hawthorns
The hawthorns are closely related to the crabapples, which constitute an even more neglected group.
They fascinated the late Charles Sprague Sargent, who named and described more than a hundred species.
The beautiful Washington hawthorn, Crataegus phaenopyrum, is one of the few offered by nurseries.
It is a spreading tree with maple-like leaves, masses of small white flowers in spring, and glistening red fruits that cling all winter.
A similar species, Crataegus Viridis, forms thickets in the low, rich ground in the South.
One of the most graceful hawthorns is Crataegus spathulata. It has masses of tiny shining leaves, a sheet of small flowers in spring, and little gleaming red fruits all winter.
The tree “weeps” delightfully in the open. Those in the Crataegus punctata group are low and wide-spreading with much larger flowers.
Louisiana offers Crataegus brachyacantha, a hawthorn with blue fruits that is a charming sight when in full fruit.
The Louisiana-French name for it is Pommette Bleu.
All the hawthorns mentioned prefer heavy, rich soil, but there are two which will thrive in sandy soil.
These are parsley hawthorn, Crataegus apiifolia; often a shrub with daintily cut leaves, and Crataegus drymophila, not much larger.
The latter is the earliest to bloom, the exquisite flesh-colored flowers coming with the unfolding leaves.
Rose-colored anthers add the last touch of beauty. These have all been tested in cultivation and have fire blight as their only enemy.
It is not advisable to plant them near pears. There are other attractive hawthorns, which are effective either as single specimens or massed in hedgerows.
Dogwoods
Before the late hawthorns have flowered, our beloved dogwood, Cornus florida, steals the show.
Whether viewing a specimen gleaming on a lawn or feasting the eye on its virginal beauty in a woodland, everyone falls under its spell.
It has the reputation of being difficult to grow, but if nursery-grown plants are secured, there should be little trouble.
The pink-flowering form is attractive and supplies a nice accent. For some reason, it demands more water than the type.
Two of the tiny-flowered dogwoods sometimes grow large enough to be called trees.
The charm of Cornus asperifolia consists of its panicles of white, red-stemmed fruits. Cornus alternifolia is similar but has blueberries.
Both of these demand heavy, rich soil.
Fringe Tree
Chionanthus virginicus crowds dogwood for a place in the sun. Its delicate white flowers have given it the appropriate name of the fringe tree.
I prefer it when treated as a shrub, but if left alone, it eventually becomes a tree 20’ feet tall with a trunk 6” inches in diameter. It delights in light soil with plenty of humus.
Worthy of attention among the early-blooming trees and shrubs is Halesia Diptera, the silverbell.
Just as the leaves appear, the twigs are covered with dainty white bells. A close relative is Styrax grandifolia, which comes a little later, with flowers like orange blossoms almost as fragrant.
Both of these trees are easy to grow and add much to the spring pageant.
Another charmer is Vaccinium arboreum which calls for close inspection as the sprays of tiny white flowers are like lilies of the valley with a delicate perfume.
The tree-huckleberry resents transplanting, so small balled plants should be secured. It likes light, well-drained soil.
Buckeyes
Aesculus octandra is almost too large to be considered in the present group of trees, but an attractive buckeye native to the Piedmont region fits in admirably.
A Georgiana is a spreading tree with showy panicles of yellow and red flowers.
After the flood of spring flowers has passed, finding a small tree (or large shrub) that carries over into summer is consoling.
Cyrilla racemiflora bridges the gap nicely by coming along in June. The numerous divergent creamy white sprays are very dainty and, by the way, wonderful for flower arrangements.
It is evergreen in the South, set off by an occasional crimson leaf. This one likes rich ground—acid and lots of hummus.
Sourwood, Oxydendrum arboreum, puts forth its long delicate sprays of small fragrant flowers at about the same time.
Even without its flowers, sourwood would be well worth growing for its unmatched color in early fall: It wants a good loamy soil and moisture.
Camellia Family Trees
Three of our most fascinating small trees belong to the camellia family:
- Stewart
- Gordonia lasianthus
- Gordonia alatamaha, The “lost franklinia
(Edit. note: Gordonia alatamaha is now called Franklinia alatamaha, according to the second edition of Bailey’s “Manual.” 1949.1 Frankly.
I have found these wonderful species difficult to grow, but I have learned their requirements.
They must have rich soil, not tight and heavy, water, and good drainage. Here in the Gulf states, they like protection from the afternoon sun.
Gordonia lasianthus is a beautiful evergreen that affords a lovely setting for its creamy white flowers.
It wants plenty of water and blooms all summer if happy. Franklinia has flowers that are more cupped than those of Gordonia lasianthus and with crimped petals.
The tree is deciduous and also blooms over several months.
Witch Hazels
Our witch hazels, Hamamelis virginiana, and Hamamelis macrophylla begin to flower when shrub-size, but become slender trees up to 20’ feet in height.
Their fringy yellow flowers are a great joy in late fall and early winter.
44659 by Caroline Dormon