Japanese Tree Lilac
Syringa reticulata

This lilac, possibly not so well known to northeastern gardeners, may be one of the most versatile. Japanese Tree Lilac, as the common name implies, is a lilac of medium proportions which opens up all kinds of possibilities in the landscape.

As an added bonus, this award winner holds its floral display after most of the other shrub-type lilacs have faded. The creamy white flowers don't have the same sweet fragrance of the traditional common varieties, but the later bloom time provides a nice way to extend the flowering season.

Japanese Tree Lilac is adaptable to a wide range of soils and exposures. It can be used as a patio tree, lawn specimen (especially if allowed to branch to the ground) or even as a small street tree. Cold-hardy, this is a tree that can add a refreshing dimension to the home or public landscape.

Leaves Opposite, simple, entire, broad-ovate, 2 to five 5 long, and 2 inches wide. Dark green color in summer; some cultivars have distinguishing fall color.

Stem Stout, shiny reddish brown, resembles cherry bark.

Size Will grow to 30 to 40 feet in height, 12 to 25 feet in spread.

Habit Classified as a large shrub, or small tree, with stiff spreading branches forming an oval crown with age. With pruning, an attractive umbrella shape can be achieved. Grows 12 to 18 inches per year.

Flowers In early to late July, or July in northern climates, creamy white flowers appear for 2 to 3 weeks. Only slightly fragrant, the flowers are 6 to 12 inches long and roughly 6 inches wide.

Culture Similar to species lilac, the tree lilac prefers full sun, moist neutral soil that is well drained. It will endure severe pruning once established. If necessary, maintenance pruning is best done immediately after flowering. This plant doesn't appreciate the hot summer sun.

Insects and Diseases Resistant to powdery mildew, scales and borer, this may be the most trouble-free lilac available. It may suffer from common lilac maladies, including bacterial blight, Phytophthora blight, leaf blights and, occasionally, injury from late spring frosts.

Hardiness Rated for Zones 4-7, although it exists in many Zone 3 locations.

Suggested cultivars 'Ivory silk:' Introduced by Sheridan Nursery in Ontario, Canada. Heavy flowering begins at a young age with a sturdy, upright habit, disease tolerant.
'Regent:' Introduced by Princeton University, offers vigorous growth and upright habit.

Propagation Difficult from seed; cuttings collected in June and treated with hormone offer a high percentage of success.

Information sources: Dr. Michael Dirr, Dr. Paul Cappiello, Jeff O'Donal.