I have a 100 foot line of property, and would like to plant my new 10 Japanese Ivory Lilac trees in Aline for privacy.
Can I plant them 10 feet apart to create a hedge like privacy barrier,
Thank you for contacting the Toronto Master Gardeners with this interesting question on growing multiple Japanese Lilac trees to create a hedge. The Japanese Lilac Tree (Syringa reticulata ‘Ivory Silk’) is a very special tree introduced by Sheridan Nurseries in 1973. It is a compact tree hardy to Zone 3 and usually flowers in June. It has an oval or pyramidal form when young but spreads to a rounded shape as it grows older. This is a very large shrub or small tree, reaching a height of about 20 to 30 feet, and normally, with about a 15-foot-spread. It is a very beautiful tree with dark green leaves, and its showy, nearly foot-long creamy-white flowering panicles have a sweet fragrance in the spring.
Syringa reticulata is frequently used as a residential street tree since it is tolerant of urban conditions, growing in poor, clay or alkaline soil. The flowers are most showy and prolific when the tree is located in full sun with good drainage. Plants in partial shade can be infected with powdery mildew, which can cause some defoliation.
You could plant your Japanese ivory lilac trees 10-12 feet apart, jig-jagging the planting, or planting in a soft curve, about 12 feet from the fence (for easy maintenance), to make the hedge look more natural. Let the lower branches at the bottom of the trunk grow out in order to create a more shrub-like shape, creating more privacy.
Pruning can be performed annually while the tree is dormant before new growth begins to appear. Pruning can also be done right after the lilac finishes blooming to ensure that you do not remove next years flowers. Lilac flowers on “old wood”, wood that was produced the previous season. If you prune your lilac in the fall or later in the summer you will remove all the flower buds.
It is also important to remember to fertilize your trees yearly with compost or composted manure to ensure that the soil pH is close to neutral, which lilacs prefer. These amendments and some good mulch will help to stimulate vigorous new growth and better flowering in years to come.
You may enjoy reading this factsheet from the Missouri Botanical Gardens: Missouri Botanical Gardens