Some trees and shrubs are at their best flowering during the summer, and because they are few, they should be known and used.
Most of the woody plants make their big show of flowers in the spring, but the following are reliable summer-blooming specimens, each one of which can be featured in almost any garden where it is hardy.
Rose Of Sharon
The rose of Sharon (Althea) is an example—a commonly grown shrub of which nearly 30 different varieties are growing in the Arnold Arboretum in Boston, Massachusetts.
Excellent seashore plants, these exotics are hardy up to Boston and Rochester, New York.
Better Varieties
The flowers are white, pink, red, or blue, wide open, and some 4” inches in diameter during the latter part of the summer.
A few of the better varieties are the following:
- Snowdrift (single white)
- Admiral Dewey (double white)
- Lady Stanley (semi-double, white to pink)
- Due de Brabant (deep pink, double)
- Woodbridge (single red)
- Boule de Feu (double red)
- Coelestis and Blue Bird (single blue)
Peculiar Feature Of Rose Of Sharon
One peculiarity about these plants is that they are very slow to produce their leaves in the spring, sometimes not until mid-June, so gardeners should not be tempted to discard them prematurely as being “dead.”
Another point to remember is that small plants have a difficult time the first winter. Hence large plants should be purchased and planted in the spring.
If pruned vigorously, the flowers will be larger, but if unpruned, the plants will grow to dense upright bushes as high as 15’ feet in situations to their liking.
French Hydrangeas
The so-called “French” hydrangeas should be mentioned, those with large clusters of pink or blue flowers and usually good dark lustrous green leaves.
Not reliably hardy north of southern New England and the mid-central United States, these are popular plants, especially on the Pacific Coast and the South. Over 50 varieties are available; many are typically greenhouse forms.
Pink-flowered varieties do best in alkaline soils, blue flowered in acid soils, and many plants will produce flowers one color in acid soil and another color when the pH is changed to alkaline.
Best Hybrids
These are especially popular in the South and have earned the name “French” because many of the best hybrids originated in France.
Coming to a less common shrub, the vitex or chaste tree has much to recommend, especially at the seashore.
There are several Asiatic varieties, ranging in height from 9’ to 15’ feet, with small, feathery, blue, white, or even pink flowers in mid-August.
Vigorous, open-growing, and exotic-looking shrubs, some have gray foliage and supply an interesting contrast because of this throughout the summer.
Interesting Gordonia Tree
The Franklinia or Gordonia tree is interesting, but unfortunately all too rare ever since it was first found in Georgia in 1770.
It has never been found in the wild again, although several people have initiated searches for it.
The first trees were cultivated in John Bartram’s garden in Philadelphia, and of course, he shipped plants to Europe.
Now it is still only available from a few nurseries. The large, pure white, cup-shaped flowers are 3” inches in diameter, with the center full of bright yellow stamens.
They begin to appear in late August and continue until frost kills the foliage. In New England, this is grown as a tall shrub, cut back some winters by severe cold but worth trying.
From Philadelphia southward, it grows as a tree up to 30’ feet tall. When it is grown in the full sun, its peak of beauty is its autumn foliage color, a rich yellow, orange, and scarlet.
Golden Rain Tree
The golden rain tree (Koelreuteria paniculata) is popular in the Ohio Valley.
A native of the Orient but long in America, this small tree (usually under 30’ feet tall) produces large panicles of small, brilliant yellow flowers in the early summer, and the large bladderlike fruits are conspicuous.
Although somewhat weak-wooded, it is still a good summer bloomer, especially from extreme southern New England southward and towards the Midwest.
Japanese Pagoda Tree
The Japanese pagoda tree (Sophora japonica) is a sturdy shade tree growing 75 feet tall as far north as Boston.
In its native habitat in the Orient, it is planted around Buddhist shrines and pagodas. Still, in America, we like it for its wide-spreading habit, ability to withstand city growing conditions, and profuse, small, yellowish pea-like flowers produced in large clusters at the end of August. It is the last of the larger trees to bloom.
Native Sourwood
Another excellent summer-blooming tree is the native sourwood (Oxydendrum arboreum), native in the eastern and southeastern United States but hardy all the way up to Boston and Rochester, New York.
This, in the North, is usually a small tree—under 30’ feet in height—but in its native habitat, it can grow to 75’ feet.
It has many characteristics of unusually good garden merit, the best of which is its delicate terminal and often drooping clusters of small white flowers in late summer.
Each flower is somewhat similar to that of the blueberry. When these fade, brownish seed capsules are formed that may remain all winter.
The foliage is also excellent, for it is glossy, each leaf somewhat the same size and shape as the mountain laurel.
In the fall, these turn a brilliant scarlet, making this one of the best of all trees for autumn color.
Added to these excellent characteristics is the fact that it is not seriously affected by insects or diseases, but, being a member of the heath family, it does best in acid soils.
Stewartias
Last but certainly not the least of these summer flowering trees are the stewartias, of which there are several, hardy up to Boston and Rochester.
These are small flowering trees with 2” to 3-inch white flowers in July, resembling single flowered camellias, with conspicuous bright yellow stamens in the center.
The smallest, Stewartia ovata Grandiflora, a native of Georgia and only 15’ feet tall, has purple stamens.
The largest is the Japanese stewartia, up to 60’ feet tall, and the Korean is about 45’ feet tall. All have beautiful, mottled, varicolored bark of ornamental interest throughout the year.
These are difficult to establish, but once they grow, they are among the best of all for year-round interest.
44659 by Donald Wyman