For Release On Or After 08/20/10

Nothing epitomizes the summer season in Louisiana more that the crape myrtle. This small tree packs a powerful punch of color over an amazingly long season. But other summer-blooming large shrubs and small trees can do a lot to contribute to the summer display. Here are a few.

Vitex or chaste tree

In gardening, flowers that are called blue often have a slight lavender tint or may be bluish purple. True blue flowers are few and far between. Such is the case with vitex. For about a month this deciduous large shrub or small tree produces showy, 5- to 7-inch spikes of small lavender blue flowers from late May through June. A second flush of flowers often appears in July or early August, especially if the old flower spikes are removed to prevent seeds from forming.

Vitex is an attractive plant with star-shaped, aromatic leaves that are grayish green on top and gray underneath. The natural shape is shrubby, but with some judicious pruning over time the plant can be trained into a delightful small tree. Mature height is about 10 to 15 feet with a spread of about 8 feet. Growth is rapid.

Rose of Sharon or althea

The fact that althea is a species of hibiscus is fairly obvious if you look carefully at the flowers. Like crape myrtles, altheas have a very long blooming season and come in a variety of colors. Flowering generally begins in May or early June and continues through summer. Flower colors include white, pink, white with a red eye, lavender blue, purple and light red. And the flowers may be single or double. Like so many other traditional Southern plants, althea is native to Asia – as are gardenia, azalea and crape myrtle, to name a few.

This plant is commonly grown as an upright, large shrub or multi-trunked small tree. It generally grows 8 to 12 feet tall and 4 to 6 feet wide. It is deciduous and, unlike the tropical hibiscus – another great large shrub for summer color – it is perfectly hardy here.

Confederate rose

Another species of hibiscus that produces a long season of summer flowers is a type of the Confederate rose. You may be familiar with the traditional double Confederate roses that bloom in fall. Exquisitely beautiful, the flowers open white or pale pink and change to dark pink/light red by evening. The species name mutabilis means changing or subject to change and refers to the changing flower color.

For summer blooms, however, you want the form called Rubra. This plant produces single, light red flowers all summer from May to October. Like all of the Confederate roses, Rubra grows to be a large plant easily reaching 8 to 10 feet or more. Numerous shoots from the base give the plant a shrubby look, but I have trained them to tree form as well. This plant drops its leaves in the winter and, while they may be killed back slightly or to the ground depending on how cold it gets (temperatures in the teens freeze them to the ground), they reliably regrow each year.

Whiteflies are a major pest along with the sooty mold they cause. One treatment with the insecticide imidacloprid in the spring when they leaf out will prevent whiteflies all summer.

Oleander

What would summer be without our magnificent oleanders? These massive shrubs that grow 10 to 12 feet tall and wide produce masses of star-shaped flowers in shades of red, pink, white, peach, salmon and pale yellow. Dwarf oleanders reach about 5 feet by 5 feet and are available in pink and salmon.

If the winter is mild, blooming commences in April and occurs in several flushes through the summer. Although typically grown as a shrub, their large size lends them to pruning into a tree form as well.

Oleanders are evergreen, drought-tolerant and virtually carefree. They are prone to the small, white oleander scale insect, but this pest rarely causes major problems. It can be controlled with oil sprays – use light, paraffinic oils this time of year, such as Summit Year-Round Spray Oil – or systemic insecticides such as imidacloprid or acephate if needed. Although a surprising number of ornamental plants are poisonous, oleander is particularly toxic and should never be used around children’s play areas.

Still more summer-blooming large shrubs and small trees are worth considering to add to your landscape. These include angel’s trumpets, with its large, fragrant trumpet-shaped flowers blooming in mid- to late summer; harlequin glory bower, a hardy, small tree that produces clusters of wonderfully fragrant white flowers in July; butterfly bush, a large-growing shrub with flower spikes in white, burgundy, pink and purple; and Southern magnolia, especially Little Gem, which repeat blooms until October.

Rick Bogren