USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Planting and Care for Lilac

Selecting a Planting Site

Please use these guidelines when selecting a planting site for your cloned lilacs.

  • Choose an unshaded place, away from buildings, trees, or any other obstacles. (The minimum distance from the base of any obstacle should be at least two times the height of that obstacle).
  • As much as possible, choose a place away from footpaths, sidewalks, and roads.
  • At weather stations, plant the cultivars about 12 to 15 meters (40 to 50 feet) away from the station to avoid any interference with the station instruments.
  • Choose a place where you can observe the plants easily each day.
  • Choose a place where there is no risk of the plants being trampled by people or animals.
  • Choose a place where excessive amounts of snow do not accumulate from drifting or plowing.
  • As much as possible, choose a level surface; if you have a hilly landscape, avoid, if possible, the low areas that can unduly delay shrub development in the spring.
  • Plant in soil commonly found in the area; avoid planting in soil, such as a garden, that has received heavy applications of manure or compost.
  • Leave at least 5 m (15 feett) between plants.
  • Choose a location that will not create any special microclimates (such as frost pockets or windy slopes) for the plants.


The quality and validity of data depend strongly upon healthy shrubs, so you should observe the following practices to insure their health.

  1. As soon as you get the plant, if it is "bare root" (not in soil), soak the roots in a pail of water for a few hours. If the plant is potted (in soil) make sure the soil is moist (add water as needed) and then you can immediately proceed to the next step.
  2. Dig a hole deep enough to just cover the roots and wide enough so you can spread roots horizontally.
  3. Mix about 1/2 cup of bone meal or superphosphate into the soil in which the plant is going to be planted. In heavy clay soils or in very sandy soils, add equal parts of peat moss or compost to backfill soil to improve growing conditions.
  4. Water the new transplant, until soil is soaked, at least once a week for the first month.
  5. Apply either a dry fertilizer such as 10-10-10 or a liquid soluble one during the first growing season, according to label directions.

Annual Care

  1. Spread 1 cup (1/8 Ib or 50 g) of 5-10-10 fertilizer or its equivalent evenly around each plant. Shrub fertilizer stakes may be used instead.
  2. Keep the soil within 30 cm (1 ft) of the base of each plant free of grass and weeds with a mulch of peat moss, bark, well-rotted sawdust, wood chips, or similar organic material.
  3. During a long dry period, you may have to water the plants.


Plants should be pruned every 5-10 years to maintain good shape. Prune lilacs immediately after bloom in spring because the following year flower buds are formed on new wood that grows after bloom. Avoid fall pruning because it will destroy the buds for the next year. Old, dried-up flowers may be cut off if desired so that the shrubs do not look unsightly.

Honeysuckle, on the other hand, should be pruned when plants are dormant. However, midwinter pruning is advised only in warm climates where plants do not lose their leaves in winter. A general rule is to prune a month before the plant normally begins to leaf out or about 6 weeks before it reaches first leaf stage.

For both species, one or more of the older main stems at the base of the plant may be removed and some, or all, of the remaining stems trimmed back to maintain the size and shape desired. Never remove more than 1/3 of the plant at any one time.

Lilac - powdery mildew

Powdery mildew


Lilacs and honeysuckle are relatively resistant to insects and diseases. Occasionally they may be affected by powdery mildew, leaf spot, scale, or aphids. Control measures rarely are needed except for scales (lilacs) or aphids (honeysuckle). Should these diseases or insects become serious, regular applications of a pesticide may be necessary. Contact the Agricultural Extension Service in your state, province, or county for the latest control recommendations.


Place a wooden or metal stake beside each new plant to indicate clearly its location. This will help to prevent accidental damage by lawn mowers or people. In some locations rodents, such as rabbits and mice, may severely damage the plants. Wire-mesh guards around the base of the plants help to control such damage. Larger wire guards will be necessary to protect the whole plant in areas where deer or other large animals browse.

For winter protection in areas of little snowfall, 2 to 4''; (5 to 10 cm) of mulch around the base of each plant will protect its roots from frost damage. To prevent breakage from ice, wrap stems together loosely with twine or place burlap (such as from a feed bag) on a frame over the plant. Do not use plastic.