Eggshells can be added to the soil anytime. Pulverize them and sprinkle them around your lilac bushes, gently turning them into the top few inches of your soil. Take care not to damage any roots and water thoroughly to help leech the eggshells into the soil.

When To Prune As a general rule for all lilacs, they should be pruned immediately after they’re done flowering in the spring. Since lilacs set next year’s flower buds right after the current year’s flowers have faded, pruning later in the summer or fall will result in cutting off many or all of next year’s flowers.

There are several techniques involved in pruning a lilac bush:

1. Get rid of dead, broken or diseased stems first, as well as any weaker branches. In addition, cut branches to prevent rubbing or crossing.
2. Remove old stems that are thicker than two inches.
3. Manage sucker growth.

Using Fresh Coffee Grounds Grow lilacs in fertile, humus-rich, well-drained, neutral to alkaline soil (at a pH near 7.0). If your soil is in poor condition, add compost to enrich. Lilacs don’t like wet feet and will not bloom with too much water.

Lilacs grow best in slightly alkaline (6.5 to 7.0 pH), moist, well-drained soil. Adding bone meal to the soil can make it more alkaline. If you choose to feed your plant in the spring, you can use Miracle-Gro® Shake ‘n Feed® Flowering Trees & Shrubs Plant Food. Lastly, Lilac plants do not like acidic soil.

Most shrubs that flower in the spring, including lilacs, should be pruned shortly after they have finished flowering, says Doris Taylor, plant information specialist in the Plant Clinic at The Morton Arboretum. These plants grow their flower buds each summer for the next spring’s bloom.

Do lilac trees bloom more than once a year? Most do not, but the Bloomerang lilac tree blooms in spring, takes a pause in early summer, then blooms again from summer all the way to the first frost of the year.

While lilacs are quite hardy plants on their own and will produce more blooms every year, pruning lilacs is one of the best ways to keep them blooming year after year. Pruning a lilac bush removes the old wood and facilitates new blooms in the spring.

Bloomerang Purple lilac is the original reblooming lilac. It blooms in spring along with other lilacs, takes a brief rest to put on new growth, then blooms again from mid-summer through fall. It doesn’t only bloom once in spring – it also blooms summer through fall.

Your bush might have a bacterial plant disease called lilac blight. The dark black streaks on one side of young shoots show the progression of the disease. The flowers will wilt and turn brown and unopened flower buds become blackened.

Too much water can drown the plant. Careful not to underwater the shrub, as lilacs will not thrive in dry soil. Moisten the soil to a 12 inch depth, usually 2 inches of water per plant. Do not overwater your lilac.

A dying lilac bush may appear weak or yield only a few spring blooms. This is commonly caused by overgrowth and poor plant nutrition, which may be remedied with heavy pruning and steps to ensure the soil contains vital nutrients.

How to Water Lilacs. After planting, check plants often and water whenever the top inch of soil becomes dry, usually once or twice per week. Count to 10 while you water to make sure you’re giving each lilac plant enough moisture. (Leaves will begin to droop if the plant is getting too dry.)

Water regularly to establish a deep root system. It is best to water them at soil level and avoid overhead watering. Once established, lilacs are water wise. Water weekly in dry conditions, more often in extreme heat.

You can generally expect shrubs and trees to develop roots that extend out about one and one-half times the length of the branches. Lilac roots are not considered invasive, but a shrub that’s 10′ wide will probably have roots extending out about 15′ in all directions.

Are Lilacs Poisonous to Dogs? Lilacs do not contain any chemicals that will poison animals or humans, nor do they irritate the skin. Even though lilac stems, leaves, and flowers pose no health threat to dogs, it is a good idea to keep your dog from chewing on the plant.

Lilacs produce seeds in seed heads. Lilac bushes can be propagated from those seeds. The seed heads form after the flowers finish blooming. They are brown, large and not very ornamental.