Lilac Care and Growing Tips by a Professional Grower

A healthy lilac garden is easier than you think. Lilacs are low-maintenance shrubs. They offer good summer shade after they have reached several feet tall and they provide privacy to neighboring properties. With just a little care and maintenance, and the knowledge of how to replenish the old wood with new shoots, the shrubs will last a lifetime.

How to Care for a Lilac in Five Steps

  1. Moisture considerations

    Lilacs do not like to get their feet (the roots) wet for a prolonged period of time. They do best on hillsides, slightly elevated areas, or level ground where there is good drainage. Their roots run deep. If you have an extended dry period of drought, water infrequently but thoroughly. Lilacs do not grow well in lowlands where water tends to collect for prolonged periods of time.

  2. Weeding

    Weed around your lilac bush to maintain a clean, aesthetic look. Pile mulch high to retain some soil moisture and to keep weeds down, but not so thick that new shoots are hampered from sprouting and developing. Two to four inches will do nicely. Lilacs will tolerate almost any kind of soil, from clay to sand, with a pH of 6.0 to 7.0. Like any plants, lilacs will benefit from compost and humus worked into the soil to help retain water during dry spells and to provide additional nutrients.

  3. Fertilizer

    You do not need to provide frequent fertilizer or organic feeding for your lilacs. Use a general-purpose fertilizer in early spring or one high in phosphorus to promote blooming. Too much nitrogen in the soil will result in poor blooming. Repeat the use of a general-purpose fertilizer after the flowers have died off. An old stand-by from Grandfather’s day was to spread your fireplace ash around the drip line of your bush for bigger, better blooms.

  4. Pests and Disease Prevention and Treatment

    a. Insects
    Lilacs are fairly hardy plants. Most insect pests do not bother them to any serious degree. For occasional insect problems, such as aphids or borers, treat with an insecticidal soap.

    b. Pests
    Mice and moles are one of the biggest pests of lilacs. During hard winters, rodents will chew on the bark of the stems at or near ground level and can kill a plant. They harbor under the mulch you amply provided and feed on your plant, especially in the harshest of winters. Try to pull the mulch away from the base of your plants, most lilacs are rock-hard plants that don’t mind the cold. That mulch that warms the roots is also a nice warm condo with a full refrigerator for mice or voles.

    c. Disease
    Lilacs are susceptible to a couple of plant diseases. Most common is powdery mildew. Powdery mildew occurs most frequently during hot and humid weather. Treat any outbreak early. For a green solution mix a half a cup of milk in a gallon of water and spray your plants. Repeat as necessary. This is known in the plant world as biological counter-culture. The lactobacillus that sours milk colonizes the leaves and leaves no room for mildew spores! Good medicine from Mother Nature! For majorly destructive outbreaks, trim away infected branches and dispose of them. Do not add to the compost heap. While this disease can cause major problems with many tender fruits, flowers and vegetables, it will generally not cause long term serious problems for your bush. Powdery mildew’s unsightly appearance is the biggest negative for lilacs, but it’s so easily remedied.

  5. Propagating Lilacs

    Most of the lilacs we’ve discussed are clump forming colonizers that sucker freely from the base and this can be a source of new lilacs to grow and give to friends and family. Simply find shoots growing out from the main clump and dig down to expose the roots for those canes and sever between the mother plant and your new clone. Plant it in the same soil it came out of with some compost or humus added and water regularly until it starts to take off. You’ll know what I mean. Lilacs are not hesitant growers and you’ll see your plant grow quickly.

    If you want to be the next Father Fiala and breed lilacs you need to wait until one is in bloom, pollinate it with the pollen from a different lilac, bag the blossom so other pollen can’t contaminate our cross, wait months for the seed to mature, give the seeds a winter vernalization… or you could dig up the clonal clump and knock two years off the timetable; you be the judge.

Growing lilacs is easy

Despite all the dire pronouncements, lilacs are really very easy to grow. Just follow these few tips, and the worst that Mother Nature can throw at your plants will roll right off them. The lilacs are some of the most durable, fragrant, beautiful flowers in the world. These old fashioned plants may have been Grandma’s favorite, but they will certainly find a place in the gardens of the future.