About
Lagerstroemia subcostata is a deciduous tree in the family Lythraceae, native to Japan, the Ryukyu Islands, Taiwan and southern China. It is recognised at least at the variety level, with var. fauriei recorded from Yakushima, Tanegashima and the Ryukyus and var. subcostata across the species range. In the UK it flowers from July to September. Crosses between var. fauriei and Lagerstroemia indica produced the hybrid Lagerstroemia × egolfii, which has yielded numerous cultivated forms.
About the genus
Lagerstroemia, commonly known as crape myrtle, is a genus of deciduous and evergreen trees and shrubs native to the Indian subcontinent, southeast Asia, northern Australia, and other parts of Oceania, cultivated in warmer climates around the world. It is a member of the family Lythraceae, which is also known as the loosestrife family. These flowering trees are beautifully colored and are often planted both privately and commercially as ornamentals.
Wikipedia contributors, "Lagerstroemia", CC BY-SA 4.0 — Lagerstroemia
In the garden
Lagerstroemia subcostata belongs to the genus Lagerstroemia within Lythraceae and occurs naturally in Japan, the Ryukyu Islands, Taiwan and southern China; it has also been introduced to the Philippines. The species is treated at least in part as two varieties: var. fauriei, known from Yakushima, Tanegashima and the Ryukyus, and var. subcostata across the broader range. Varietal material from this species has been important in hybrid breeding. When var. fauriei is crossed with Lagerstroemia indica the result is Lagerstroemia × egolfii, a hybrid that has produced many cultivars and is widely planted as an ornamental in the United States. That breeding history explains why material related to L. subcostata appears in collections and nurseries under hybrid or cultivar names. In the UK the species flowers from July to September, so its main interest to gardeners is as a summer-flowering tree. Where it appears in cultivation it is often valued for that mid- to late-summer display, and for its role as parent stock in hybrid crape myrtle breeding programmes. The use of var. fauriei in crosses remains a notable part of the species’ horticultural significance.