Fragrance is such a desirable attribute in garden flowers. While many of the scents of summer have begun to fade into pleasant memories, one that’s just recently unfurled its fresh, lilting fragrance is the summer lilac (Buddleia davidii), often referred to as the “butterfly bush.”
Somewhat reminiscent of baby powder, the light scent of the lilac-colored blossoms mingles wonderfully with the spicy scent of nicotianas, making me pause from garden chores to take in this intoxicating perfume.
Aside from the light purple species, several dozen varieties of B. davidii are offered by American nurserymen in varying shades of purple, pink, red, white, yellow and orange.
‘Royal Red’ is reputedly one of the best reds, with panicles of flowers up to 20 inches long.
‘Black Knight’ presents an interesting contrast, with its blackish-violet flower spikes.
The Nanho series has more of a dwarf, spreading habit – reaching about 4 feet high and wide and coming in white, blue and purple.
A very new cultivar, called ‘Blue Chip,’ grows only 20 inches high.
‘Harlequin’ and ‘Santana’ both have variegated leaves.
‘Honeycomb’ boasts of golden-colored blossoms and a blooming period from June until frost.
The lure of their nectar
As their name implies, these shrubs will draw hordes of butterflies to your yard in search of their fill of sweet nectar.
Monarchs, fritillaries, swallowtails, sulfurs and skippers are just a few butterfly species that find this plant so alluring. I’ve often counted more than a dozen butterflies on a single bush!
In all but the more sheltered locations, I’d have to classify the summer lilac as a semi-woody shrub or even a woody perennial.
Tall, arching branches may grow to 6 feet or more by summer’s end, their tips encased by panicles of sweet, pastel-colored, orange-centered blossoms.
When to prune
Often, most or all of the stem will die back over the winter, but the roots remain alive. Since this plant blooms on new wood, loss of old branches is not a problem.
I don’t cut back the dead stems until I see new growth in the spring and the chance of a late frost is slight. This measure affords some protection to the tender new growth emerging at the base, if the temperatures dip drastically.
Summer lilacs are not fussy about their site but will flower most profusely in full sun. Any well-drained site will do.
I fertilize and mulch my plants in the spring, after cutting back the old, dead growth and pretty much leave them alone, except for gathering some flowers for indoor arrangements.
I really have not noticed any insect or disease problems on this plant in all the years I have grown it.
Reputedly, some buddleia species and cultivars may produce viable seed and may even be considered invasive in certain situations. Even though I started my plants from seed more than a decade ago, I have yet to find one seedling. Just the same, be vigilant and keep an eye out for “volunteers.”
Where to place the plants
Because most summer lilacs have a loose, sprawling appearance, some thought should be given to their placement in the landscape.
Also, the fact that they often die back in the winter and are slow to get going in the spring may make them unsuitable for areas like foundation plantings, unless you don’t mind temporary gaps in cover.
I do find summer lilacs work well in the back or corners of a perennial bed, since their growth habits mimic those of perennials.
Add a few other butterfly attracting plants like coneflowers, asters, boltonias and sedums for a late blooming garden alive with color and motion.
Fountain butterfly bush
One other buddleia species worth mentioning – which is hardy in New England – is the fountain butterfly bush, B alternifolia. The branches are winter-hardy, which is fortunate, because it blooms on old wood.
In early summer, clusters of honey-scented, mauve-colored blossoms cover the gracefully cascading stems.
Fountain butterfly bush can attain a height of 10 feet, but its airy, delicate nature makes it a suitable backdrop in large perennial plantings or for shrub borders.
Like many spring and early summer flowering shrubs, its beauty is striking but fleeting – blooms last but two weeks.
Whether for the gaily colored panicles of flowers, the delightful fragrance or its affinity to butterflies, perhaps summer lilacs are just the ticket for late summer color in your garden.
If you have questions about growing summer lilacs or on any other home and garden topic, call the UConn Home & Garden Education Center (toll-free) at (877) 486-6271, visit www.ladybug.uconn.edu, or visit your local Cooperative Extension Center.