Ivory Silk Lilac Tree (Syringa reticulata ‘Ivory Silk’)

Ivory silk lilac, a popular low-maintenance cultivar of the Japanese lilac tree, grows a little shorter than the species plant. It is a single-trunked small tree or large shrub with panicles of creamy white flowers with very little fragrance. Ivory silk lilac grows best in cooler climates and requires full sun and well-draining neutral pH soil.

I. Appearance and Characteristics

Award-winner Syringa reticulata ‘Ivory Silk’ (Japanese Tree Lilac) is a large shrub or small tree with an oval to rounded crown.

In early summer, a profusion of huge clusters, 6-12 in. long (15-30 cm), packed with fragrant, tiny creamy-white flowers adorn the tree. Flowering begins at a young age on this sturdy, compact tree. The blossoms give way to loose clusters of tan capsules that persist well into the winter months.

The erect branches are clothed in lanceolate to ovate, dark green leaves that remain attractive in summer. Equally handsome is the lustrous, reddish-brown exfoliating bark with horizontal lenticels, reminiscent of cherry bark. Drought resistant and free of pests and disease, this Japanese Tree Lilac is attractive as a small landscape tree or large shrub.

II. How to Grow and Care

Sunlight

This tree needs full sun. A partially sunny or shaded location reduces the number of flowers. If it is in a sunny spot, your tree will explode with huge white clusters of blooms.

Temperature and Humidity

Ivory silk lilac is not especially cold-hardy though it will only thrive in the limited and cooler USDA ranges of zones 3 through 7. However, it will not do well in hot, humid climates.

Watering

Ivory silk lilac is somewhat drought tolerant. However, in extremely dry weather, the tree appreciates supplemental water.

Water a young tree for the first two seasons to establish a strong root system and apply a layer of mulch around the base of the tree out to the drip line. Water a newly planted tree weekly at a rate of a gallon per trunk diameter at chest height.

Soil

An appealing aspect of the ivory silk lilac is its ability to grow in poor soil conditions and even where soil may be rocky or compressed. The ideal soil is average, rich in organic material, well-draining, and neutral to slightly alkaline.

Fertilizing

Applying a yearly feeding of a general extended/slow-release fertilizer formulated for ornamental flowering trees is recommended to help keep your ivory silk lilac in shape. Applying the fertilizer lightly in the spring once frost has passed should keep your tree happy and encourage plenty of blooms and foliage.

Pruning

After a few years, it is normal for an ivory silk lilac to produce fewer blooms. Maintenance pruning rejuvenates the tree and encourages new growth. Trim away 1/3 of your tree’s largest stems. Prune annually while the tree is dormant and before new growth appears.

Pests and Diseases

Common Pests and Plant Diseases

The ivory silk lilac is not bothered by many insects. Borers may annoy the tree but it is not a serious problem. However excessive boring into the branches may weaken them and they will break off. Prevent infestation by keeping your tree stress-free with water and regular fertilizing in overly dry weather. If borers attack, remove the infested, damaged branches and dispose of them responsibly.

Several diseases can affect the species, such as bacterial blight (a common concern for white-flowered cultivars). Blight is especially prevalent during wet weather and when over-fertilizing with nitrogen-heavy fertilizers. Verticillium wilt is a concern, but proper fertilizing and proper tool sanitation are the best ways to avoid this problem.

Common Problems

Ivory silk lilac has minimal upkeep as long as it’s placed in the right spot. Even though, no plant is immune to every problem so keep an eye out for a couple of signs that may need to be addressed.

• Wilting Flowers

Wilting flowers may indicate too much fertilizer or nitrogen in the soil.

• Leaf Drop

Defoliation may occur on ivory silk lilac trees planted in too much shade. The trees may be afflicted by powdery mildew, which can cause leaf drop.2

• Black Spots on Leaves

If the tree has bacterial blight, black spots or stripes may also appear on leaves and stems. Leaves will turn black and die. Wet weather causes this problem. Thin out extra shoots in the tree to give the plant air circulation.

III. Uses and Benefits

The Ivory Silk Japanese tree lilac is a versatile choice. Since the lilac reaches a height of 20 feet, you might want to use this tree in a small yard. It also works well as an ornamental focal point for a lush garden border. Make sure to keep those lower branches trimmed and tidy to help maintain its beautiful tree form.

For those spaces that need some privacy, plant these lilacs in a long row near your fence. During the growing season, you will have a great privacy border as the lush foliage offers exceptional shade. You want the lower branches to grow out at the trunk’s bottom to provide some solitude for your spaces. Those lower branches will fill in as the lilac develops into a tall flowering shrub. You should plant these trees about 12 feet apart from the center. A group of Ivory Silk lilacs planted in a slight zig-zag pattern or a gentle curve give a more naturalized appearance to your yard. Since these trees can grow thick, keep them about 12 feet away from a fence or building.

If you want an excellent tree for a parkway or street, plant these beauties between the sidewalk and roadway. These lilacs can handle salt and pollution, and they make a perfect option for urban or commercial spaces. Large parks will also benefit from the addition of the Ivory Silk. With these trees, you can expect many admirers to come and appreciate the beauty and fragrance of the Ivory Silk Japanese tree lilac.