ONE of the most beautiful summer flowering trees would have to be the crepe myrtle (Lagerstroemia indica). They are looking lovely now, and we will admire the masses of large, showy blossoms borne atop rich green foliage well into autumn.
And the crepe myrtle continues to contribute to the garden even when the flowering stage is finished, as the foliage develops rich autumn colours before falling. Then, during winter, the decorative bark and, on well-established trees, a lovely gnarly trunk, will become the feature.
Crepe myrtles are native to eastern Asia, and grow well in most climates. They are frost tolerant but also quite happy in the heat, and are drought tolerant once established. The common name is derived from the masses of delicate crinkly blossoms which resemble crepe paper. Borne at the tips of the branches, they can be in shades of white to pinks, mauves, purples and reds. The flowers last for two or three months and, if you remove spent flowers immediately, more will form.
There are many forms of crepe myrtle, from low-growing ground covers to shrubs and trees to six metres or more. The Indian Summer range has been specially bred to resist powdery mildew. Bred from Lagerstroemia indica and a less common species, Lagerstroemia fauriei, they come in a variety of colours and growth habits, ranging in size from 3m to 6m. Each one is named after an American Indian tribe. Acoma has white flowers and grows to about 3m, whereas Natchez, the other white in the series, grows to 6m. Lipan, Tonto, Sioux and Yuma are shades of pink, growing 3-4m tall. Biloxi is a taller pink variety, growing to about 7m. Tuscarora is rose red, and grows to 6m. There is also a mauve form, Zuni, which grows to 3m.
Crepe myrtles require a sunny position. If growing in too much shade they will become weak and spindly, and prone to borer attack. They also appreciate good air flow in summer to reduce the incidence of powdery mildew. Remove lower growth to create a strong and attractive trunk, but avoid damaging the roots or lower trunk as this may cause suckering. Of course, mulch well to prevent weed growth, conserve water and prevent suckering.
You can remove spent flowers to encourage more to form during the flowering season. Then in late summer or autumn, when the flowers have finished, give the plant a light prune all over to keep it tidy. You can prune to shape during winter. Some gardeners like to prune them quite severely. But this heavy pruning can interfere with the naturally elegant vase shape that crepe myrtles tend to develop. So if you don't want the tree to grow very tall, plant a smaller variety rather than relying on hard pruning to control size.
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