Green County MGA

Green County Master Gardeners Association, Wisconsin

Lilacs Fill May Air

During the month of May the fragrance of lilacs is in the air.  Lilacs originated in Europe and Asia, and were brought to America in the mid 1700’s.  They have long been a garden favorite.  Before deciding what lilac cultivar you would like to plant, there are some factors to consider.

Lilacs come in a range of color, with lavender being the most common.  Although color choice is often our focus, it is best to first consider the plant size.  Lilacs come in many sizes and shapes and thus offer a wide variety of landscape uses.  Small lilacs can be used as foundation plants near your home.  These dwarf cultivars mature to a height and width of 4-6 feet.  The larger varieties offer great privacy as a shrub border.  These lilacs can grow 12 feet tall and 10 feet wide.  They do this by sending up suckers which is new root growth.

The bloom period for lilacs ranges from 7 to 14 days.  The choice in cultivars provides for an early, midseason, and late bloom.  By planting a variety of species it is possible to extend the flowering period to 5 or 6 weeks.  It is also a good idea to consider the plant’s ornamental features.  Some plants have small, fine textured leaves while others may have variegated leaves.  This helps make the lilac a beautiful specimen plant that provides beauty beyond the bloom period.  Some species even provide good fall color.

Select a sunny site to plant your lilac, one that will provide at least 6 hours of direct sunlight each day.  This is important for setting flower buds for the spring bloom.  The planting area should have good drainage.  This can be improved by incorporating organic matter, such as compost, into the planting hole.  Lilacs need to be watered two or three times weekly for the first month and then provided about an inch of water once a week throughout the remainder of the growing season.  This will help the plant get well established.  Mulching around the base of the plant also helps retain moisture and keeps plant roots cool.

Pruning techniques are important in ensuring spring bloom.  Newly planted lilacs will not need much pruning for the first 2 to 3 years.  Pruning recommendations will depend on the plant’s bloom period, growth pattern, and location.  Ideally pruning should be done in March when the plant is still dormant.  During this time of year it is easier to see what you are cutting out, as well as not having to be concerned about insect and disease activity.  The drawback to pruning at this time is that some flowers will be sacrificed.  The next best time to prune your lilac would be right after flowering but before the plant sets flower buds for next year’s bloom. This simply means to try to get the pruning done within a week or two from the end of the flowering period.

Lilacs grow well in our Wisconsin climate.  It is a flowering shrub that adds beauty and fragrance to your landscape.

Until next time…Happy Gardening!

Nina Binkley, UW Extension master gardener volunteer