Archive for February 7th, 2010

In “The Waste Land,” T.S. Eliot wrote:

April is the cruelest month, breeding

Lilacs come in several forms (bush, tree, miniature) and colors, usually in shades of pink, white, and purple, although yellow lilacs are available.

Lilacs out of the dead land, mixing

Memory and desire, stirring

Dull roots with spring rain.

Winter kept us warm, covering

Earth in forgetful snow, feeding

A little life with dried tubers.

But if you want to see lilac flowers in April (or more likely, May, here in Southcentral PA), take steps now (in late winter–February) to make sure your lilac bushes are in top shape.

Lilacs are one of the easiest, most trouble-free flowering shrubs you can grow. They like slightly sweet soil (pH 6.0 to 7.0), but will tolerate just about anything except wet feet; these are not plants for marshy areas. They also require full sun; if you plant them too near a wall or shady trees, they’ll tend to lean out in search of light and their flowering will not be as profuse. With their deep, heavy roots, lilacs are extremely drought-tolerant once established. New plants should be watered regularly for the first summer, but once they’re growing well, a couple inches of moisture-conserving mulch will hold them through all but the very driest weather.

Begin your annual late-winter lilac care with a thorough clean up. Remove weeds and vines. Japanese honeysuckle (Lonicera japonica) is a real pest here, and it can smother a lilac in a couple of years. Even a small vine will be competition enough to reduce bloom.

Next, remove dead wood. You’ll very likely find quite a few long, slender, whiplike stems (called watersprouts) coming up from the base of the bush or along the main branches, and a number of these will be dried up and dead. Snap or cut them off; their loss is no big deal. If you see tiny holes in any of the biggest trunks, your lilac has borers. More a nuisance than a disaster, saw out and burn (don’t compost) affected trunks. Lilac borers only attack the oldest wood, and since it’s good practice to remove a few of the oldest stems every couple of years to keep the bush vigorous, these borers aren’t usually much of a problem.

Thin out the bush a bit, removing one or two of the very biggest stems (if you have a tree lilac, don’t touch the main trunks, but do try to remove a couple of the biggest, oldest branches). If your bush has a lot of live, vigorous sprouts (called suckers) coming up around the base, either cut some of these back to ground level or dig them out to replant as new little lilac bushes.

If you did not remove the dead flowers from last year’s bloom, do that now. Removing the spent blooms forces the energy that would have gone into seed (useless for most purposes) back into forming next year’s flowers. Make a habit of removing as many spent lilac blooms as you can every year, after the bush is through flowering. (Another good reason to gather lilacs into bouquets to bring indoors and give as gifts!)

Once you’ve finished pruning, spread wood ashes thinly around the base of the lilac, extending out as far as the drip line (the outermost reach of the branches). Sprinkle on a little ground limestone and as much compost or well-rotted manure as you can spare. Spread mulch: wood chips, ground leaves, and “beauty bark” are fine mulches for lilacs; avoid grass clippings and fresh manures—the excess nitrogen they add to the soil may produce a big flush of leaves and new growth, at the expense of flowers.

Lilacs usually bloom at about the same time as mid-season tulips, and they look fantastic with white, pink, or purple tulips to pick up their colors, and with yellow or red tulips as an accent.

The worst disease of lilacs is powdery mildew, which, when severe, can defoliate a shrub, although it rarely kills. It is unsightly, though, coating the dark green leaves with a floury white.

Treat it by mixing a half-cup of cultured buttermilk milk with a gallon of water and spraying the entire bush. (If you can’t find cultured buttermilk, substitute yogurt instead.) The slight acidity of the milk, as well as the live acidophilus culture in the milk/yogurt, will be enough to knock back the growth of the mildew.

When planting lilacs, site the bush near a porch, patio, deck, window or doorway, so that, on a warm spring evening, you can enjoy the heady fragrance as you watch the sunset.