Planting Lilacs

The Sensation Lilac is noted for the white, picotee edge on each flower. More varieties are available in the Landscape Plantings department.

Lilacs are among the most carefree of all shrubs. Their needs are simple: plenty of sunlight, good drainage, fertile soil and annual pruning. Choose your planting site carefully and the only care you'll need to provide is yearly pruning to maintain a nice shape. In the spring, you'll be rewarded with clusters of fragrant blooms.

Lilacs can be planted in spring once the ground has thawed or in the fall before the ground freezes. In spring, lilacs are shipped dormant and are likely to have bare roots and no leaves or buds. Please be assured, the lilac is not dead, only "sleeping." Upon arrival, remove any packaging from the root system and soak the roots in tepid water for 10 to 15 minutes.

In late summer or fall, lilacs may be shipped with soil and have a complete root system with leaves on the stems. Upon arrival, soak the roots and root ball in water for 10 to 15 minutes.

If you can't plant the lilac right away, soak the roots as described above, then plant the lilac temporarily in a holding bed. Set the lilac at an angle ("heeled") and entirely pack the roots with soil. Add additional soil and keep the soil moist until you are ready to plant.

There are four important areas of lilac care:

• sunlight
• drainage
• soil
• pruning

Choosing the planting site: Avoid planting lilacs along walls or among large trees (or trees that will grow tall). Use complementary shrubs, plants, or other garden outcroppings to enhance the appearance before and after bloom. Space lilacs no less than 6 to 10 feet apart. Crowding requires more frequent and drastic pruning.

Sunlight: Make good use of available sunlight; try a south or southwest spot out of the way of doors or windows. Lilacs require a minimum of six hours of direct sunlight daily. The amount of sunlight dictates the appearance, color, and quantity of bloom. Too much sunlight is better than not enough.

Drainage: Good drainage is characterized by the soil's ability to retain sufficient moisture to nourish the root system while still being able to drain off excess moisture. Lilacs do not thrive in soggy soil.

Before planting, try digging a hole about 8 inches in diameter by 12 inches deep. Fill the hole with water. If the water has not drained after one hour, improve the drainage or move the plant to another site.

To improve drainage:

• Remove the topsoil from the actual planting site (an area equal to 2 to 3 times the lilac's root system) and reserve.
• Mix sand and/or fine gravel 6 to 10 inches deep into the subsoil (not the topsoil)
• Mix the reserved topsoil with peat, vermiculite or other porous amendment to cover the root system when the lilac is planted.

The planting hole should be deep and wide enough to accommodate the plant's root system. We recommend adding compost, bonemeal or an all-purpose fertilizer to the planting hole. If your soil is acidic, add some garden lime.

When planting, place the top of the root ball level with the surface of the hole. If the lilac is bareroot, the top layer of roots should be a few inches below the surface. When filling in with soil, it is important to water well, but do not flood, and avoid compacting the soil around the root system. The idea is to remove air pockets, yet keep the soil porous.

Remember to water your lilacs regularly throughout the summer. During the dry season, water more frequently to keep the leaves robust, not limp.

Fertilizer should be applied at the base of the plant early each spring to help provide the plant with nutrients for the coming year. Buds are set the previous year so the fertilizer will feed this year's leaves and next year's bloom. We recommend our Organic Flower Fertilizer.

Lilacs love a sweet soil. If your soil is acidic, adding garden lime in the fall will help the soil stay alkaline.

Using mulch will help hold water in the soil and reduce heat stress. If you see the leaves getting limp during summer it is a sign that the plant needs to be watered.

To encourage repeat blooms, the Josée dwarf variety must have its dead flowers removed after each bloom. When blooms have faded, remove the flower heads by cutting just below the individual flower heads. This will stimulate the production of new flower and leaf buds on the plant. All lilac varieties will benefit from regular deadheading.

Lilacs do not require annual pruning, but cutting off blooms from main stems within a week after blooms have faded will help the plant concentrate on preparing more flower buds and not seeds. If your lilacs become too tall, and the number of blooms declines, you can rejuvenate the plant by cutting one-third of all main stems that have a diameter of at least 1.5 inches.

Cut these main stems down to 12 to 15 inches from the soil. This will stimulate the growth of new shoots. Pruning in this way over a three-year period will refresh the plant while it still continues to flower.

Bacterial blight: This disease is appearing more often than in the past. It occurs where there are fluctuations in spring temperatures along with cold rains. Dark blotches appear on the plant's leaves and leaves later begin to wilt and turn brown. Leaves will drop and new green shoots will have a sick, pendulous look to them.

Flower buds may also be infected and turn black. Spreading of the blight can be inhibited with a spray of copper sulphate mixture, but the best remedy is to prune off the affected parts.

Pruners must be dipped in 70% rubbing alcohol for disinfecting between cuts and before pruning other plants. Destroy the diseased leaves and branches.

Leaf roll necrosis: This is caused by air pollutants. Lilacs begin to degenerate when faced with pollution. For best results, avoid planting lilacs near roads with heavy traffic. Lilacs love clean air.

Lilac leafminer: This problem is becoming a little more common in the East. The name of this culprit is Gracillaria syringella. The leaf miner moths lay their eggs on the underside of the leaves and once they hatch the young insects begin to eat the inside of the leaves. The leaves become blackened and separate like a wafer. If you separate the leaves, the pale green worms are visible to the eye. The most effective control is to handpick and destroy the infested leaves. Sprays and dusts are usually ineffective because the larvae are protected inside the leaves.

Lilac scale: Two kinds of scale, oyster scale and San Jose scale, must be taken seriously, because they can eventually kill a plant. Scale can be brought to your lilacs via hosts such as birds and other kinds of plants such as willows and ash. Symptoms of scale are wilting and dying leaves.

Scale appears as gray or brown bumps on the bark and sometimes as cracks in the bark surrounded by white fluff. The oyster scale secretes an armor of wax in a circular pattern. Brown scales attach themselves to the bark. They are hard to kill and must be brushed off with a soapy insecticidal soap when temperatures are over 60 degrees F and the insects are on the move. If a particular branch becomes very infected you can cut it off completely and dispose of it. Apply a dormant oil to the trunk and branches before new growth begins again in the spring.

Phytophthora blight: This is a soil-borne fungus that kills the root sprouts and shoots. Found most often in wet-weather areas, it causes leaves to wilt and discolor and branches to die back. Once on the plant, the blight can spread by raindrops or water droplets splashing from one leaf to another. To control this blight naturally, we suggest using a wettable sulfate powder such as Remedy Fungicide. Be sure to prune out and destroy any infected branches during the dormant season.

Witches' broom: Witches' broom appears mostly on late-flowering lilacs. New growth is congested or dwarfed with tightly clustered shoots and tiny leaves. It is uncommon in home gardens, appearing most often in large collections.

Prune out and destroy the dense bushy growth and disinfect the shears before cutting other plants.

Lilac borer: The lilac borer is one of the hardest insects to eliminate. The borer makes its way into the cane, eating the cambium wood, which is the wood through which the sap flows.

As the wood is eaten, the branch becomes weaker, leaves begin to yellow and the branch will die. Early signs of this pest are sawdust deposits at the base of the plant and an entry hole at the trunk. The best way to control this is to cut out the weakened branch and destroy the larvae.

Mildew: Mildew is caused by a fungus called Microsphaera alni. It appears in the later part of the summer and leaves a white powder on the leaves. Spores are most active when the weather is hot and humid.

You can use a wettable sulfate powder such as Remedy Fungicide to control it naturally. You can can also minimize problems with the disease by providing plenty of room around the lilac for good air circulation. In the fall, clean up and dispose of infected leaves. To prevent spreading disease, do not put the leaves in a compost pile that will be used for the garden.

Drought: Lilacs are water-loving plants. In the summer if the leaves lose their shine, turn brown on the edges or look limp, it is a sure sign your lilac needs water.