The Japanese lilac tree (Syringa reticulata) grows taller than the typical common lilac bush, developing to heights of 30 feet. This imported ornamental produces a cream-white flower that does not possess the same aroma of the more familiar lilac types. The leaves of this lilac tree also differ from those of the common lilac, identifiable by certain features.
One characteristic of the leaves of the lilac tree are how they emerge and grow on the twigs. The leaves grow opposite each other, with pairs of leaves growing at each node on the twig. If you find leaves growing just one to a node in an alternate fashion, you will know that the tree is not a lilac species.
Size and Time Frame
The lilac tree has leaves that grow between 2 and 5 inches in length, notes the University of Connecticut Plant Database website. In some cases, the longer foliage reaches a length of up to 6 inches. The leaves develop in the early part of spring on a Japanese lilac. The tree is deciduous, so the leaves will fall from the limbs by winter.
The leaves of the Japanese lilac tree are lanceolate to ovate, according to the Missouri Botanical Gardens website. This means that some have the shape of a spear point, while others are more elliptical in their form. The leaves are simple with a single blade. The leaves differ from those of the common lilac shrub, which are heart-shaped. The bases of the leaves on a lilac tree are much rounder.
From their early stages of their development, the leaves of the lilac tree take on a dark shade of green. The tree is not at all noteworthy for any color from its foliage come autumn. The leaves never change colors; they remain the same shade of green before the tree sheds them.
Effects of Disease or Pests
Powdery mildew poses a problem for all lilac types, and the Japanese lilac tree is no exception. This type of ailment causes the leaves to take on a whitish tint to them, with the disease affecting the look of the leaves the most from midsummer to late summer. The lilac leaf miner also attacks this species, joining leaves together with a web and then eating them, leaving only a "skeleton" of leaf veins in its wake.