Beautiful Lilacs

Lilacs came to America from Europe and went west with the pioneers as reminders of homes left behind.  The common Lilac (syringa vulgaris) thrived almost everywhere, and was appreciated for its vigor, colorful blossoms and sweet fragrance.

Modern lilacs offer a wealth of choices for the garden.  Sizes range from 4 - 20’ tall.  There are early and late flowering cultivars that can extend the flowering season from late April through mid June or longer!  There are 8 distinct colors:  white, violet, blue, lilac, pink, magenta, purple and pale butter yellow (the yellow budded cultivar ‘Primrose’).  There are also bicolors such as ‘Sensation’, which has purple flowers edged in white.

Lilacs are versatile.  In bloom, they make glorious single specimens, and look beautiful when 

surrounded by spring blooming dogwoods.  Lilacs are especially dramatic when massed in groups of 1 or more variety.  Of the 23 known species and 1800 varieties available, there is sure to be a lilac for every landscape!

LILAC CULTURE

As their popularity and longevity suggest, lilacs are easy to grow.  They are rugged, cold tolerant plants for hardiness zones 3-7.  (Most actually require a period of minimum winter chill in order to flower).  Plant in early spring through fall in an open, sunny spot with good air circulation.  To grow and bloom well, lilacs need unobstructed sunlight for at least 6 hours daily.  Plant in loamy, organic, near-neutral to alkaline soil (pH 6-8) with excellent drainage.  (If you find earthworms when you dig, your soil is probably fine!)  Although lilacs are very tolerant of a wide range of soils after they are established, excessive acidity, infertility or dryness will inhibit growth and flower production, so enrich your soil as needed before planting with composted manure, and top dress annually in early fall or spring with a 1-2 inch layer of well-rotted manure or compost salted with bonemeal.  Avoid high nitrogen fertilizers, for excessive nitrogen encourages lush, leaf growth at the expense of flowers.  If you choose to use inorganic commercial fertilizer (on established lilacs only please) remember - conservative spring feeding is the rule.  You may apply a 10-10-10 fertilizer or 10-6-4 every other year according to direction.  Please do not over fertilize.  Be sure to check your soil pH periodically and adjust as needed with lime to maintain a nearly neutral soil.  Established lilacs are drought tolerant but water new plants well the first 1-3 years.  Be particularly careful to water during extended dry periods and when the lilac is in bloom - but do not drown your plant.  Overwatering is just as harmful as 

underwatering.

Good drainage is crucial!  If drainage is suspect, plant in a raised bed or on a hillside.  Use a 2-inch layer of bark mulch to control weeds and conserve moisture.  Spread mulch from the drip line to within a few inches of the trunk.  Be careful not to mound mulch around the base of your lilac.

Lilacs are easily maintained after they are established.  Apply dormant oil in April, before leaves 

appear, to prevent infestations of scale - tiny, sap sucking insects.  Space plants far enough apart in good light to assure good air circulation.  This will reduce the incidence of powdery mildew, a leaf 

disease which coats foliage with an unsightly pale film that is more unsightly than harmful.

Occasionally in late June you may notice small holes and sawdust at the base of lilac trunks.  These are signs of Lilac borer.  Borers will attack injured spots on your lilac, such as those made by mowers and string trimmers.  Simply cut back damaged wood and seal cuts with Elmer’s Glue.  Avoid problems by using more caution with your power tools.

PRUNING - Please dare to prune your lilac!  Proper pruning is one of the single most important steps to encourage healthy growth and vigorous flowering.  It discourages fungal and viral disease by improving air circulation in the plant and stimulates strong vigorous growth of young twigs and buds.

Thin out and shape your lilac each year immediately following the bloom period.  If spent blossoms are not removed; flowering will be severely stunted the following year, for the lilac will expend energy into seed production at the expense of next season’s flower buds.

Begin to deadhead as soon as flower petals start to fall.  Pinch just below the withered blossom and take care not to damage tiny, new buds that are already forming.  Flower buds for the next season will be in place by mid summer - they form on old wood (the current seasons growth) - so you cannot deadhead (or prune) in late summer, fall, winter or early spring without removing them and spoiling next years floral display.  After pruning, always sterilize your tools with a 10% solution of bleach and water.

PATIENCE PLEASE - A newly planted lilac usually takes 3-6 years to settle down and produce full size, true to type, true to color flowers in abundance.  Numerous factors play a role in the development of a lilac and its flower color.  Keep in mind the following facts as you wait for your immature lilac to grow up and bloom for the first time.

•  After planting, a lilac needs time to set down roots and establish itself in its new home.  Even if a small lilac is in bloom when you purchase it, it may not bloom again for several years.

•  Young, immature lilacs will bloom in lighter shades than older ones; lilacs will not show their true 

colors for 4-6 years.

•  The flower color of lilacs grown in lighter, gravelly, sandy soils will be more subtle and faded than the flower colors of lilacs grown in richer, loamier soils.

•  Hot, dry sunny weather at bloom time will cause lilac flowers to fade.  Cool damp weather will intensify flower colors.

•  The blossom age of flowers affects their color.  A daily color change occurs as flower buds swell, open and age.  This ‘unfolding of the colors’ is captivating and magical.  Often buds, the reverse of the petals or the outer petals are deeper or an entirely different color from the open floret.

Remember any combination of the above factors can give the same lilac slightly different shades from year to year.

TROUBLESHOOTING - If your lilac is mature enough but doesn’t want to bloom, review this checklist:

√  Does your lilac have at least 6 hours of unobstructed sunlight daily?

√  Is your soil near neutral to alkaline, well-drained, fertile but not too high in nitrogen?  Do you 

topdress with organic matter and use a mulch?

√  Do you deadhead yearly immediately after the bloom time?  Do you prune and thin out at the 

same time?

Ok, try this shock treatment!  Scrape a 2-3 inch spot in the bark of your lilac near the base of one heavy branch immediately after the expected bloom time.  A boot scrape seems to work great!

LANDSCAPING - Use lilacs in mixed borders of shrubs, in masses, as screens or backgrounds and be sure to place them in sites where their wonderful fragrances can be appreciated.

A single lilac looks lovely as a specimen if placed against a wall or wood fence.  A grouping of lilacs with just 4-6 feet between plants will create a favorite haven for nesting birds.  For a hedge, place lilacs about 4 feet apart and choose compact, small leaf types like Syringa ‘Miss Kim’ or Syringa meyeri.

Several species of butterflies appreciate lilacs as a nectar source.  Include a lilac or two in your butterfly garden to attract Tiger Swallowtails and Frilillaries.

Extend the flowering season of lilacs in your landscape by choosing a new, compact variety called 

Bloomerang!  This lovely 4-6’ cultivar blooms in the spring with an abundance of lavender flowers, then repeats again in mid summer and fall with 2 more rounds color and fragrance!