Facts about lilacs

ITHACA — Some lilac facts from Cornell Cooperative Extension:

• They are among the most hardy of ornamentals, with some able to survive a winter temperature of 60 degrees below zero.
• Southern winters are too mild for them to provide the needed seasonal rest.
• Normally, the only care needed is pruning to keep them within bounds.
• Depending on varieties, lilacs can bloom from April to June.
• Tree lilacs (Syringa amurensis) resemble small trees and can reach 30 feet in height.
• The best time to plant is in the fall, after leaves of trees have fallen, but before a frost.
• Best planted in open areas with good drainage. They grow well in all types of dirt, except for acidic soil.
• Lilacs require a minimum of care and seldom need supplemental water.
• Pruning is not needed for the first three to four years.
• But older plants may need severe pruning — about a third of the height of the plant each year for three years.
• Remove dead flowers soon after they wither. This helps ensure vigorous growth for the rest of the season and and better blooming the following spring.
• Powdery mildew is the most common disease, appearing in late summer and giving a whitish, dusty appearance. Fight it by dusting with sulfur as soon as noticed.

Source: Cornell Cooperative Extension. For the full report, go to wdt.me/extensionlilacs.