To get lilacs off to a nutrient-rich start, enhance individual planting holes by adding Miracle-Gro® Garden Soil for Trees & Shrubs with the native soil in a ratio of 50:50. This garden soil also contains phosphorus and iron to promote root growth and prevent yellowing of the leaves.
Best Fertilizer for Lilac
Lilac plants do not need a lot of fertilizer or fertilizing. We recommend a 10-10-10 fertilizer mix applied annually in early spring. (The numbers 10-10-10 represent the amounts of nitrogen, phosphorus and potassium – or as they are commonly known, NPK – in the formula).
Prune the plant annually just after flowering to improve vigour. Remove weak branches until you have a clump of seven to ten stems of varying ages. Thin out the top growth to let sunlight into the middle of the lilac. New buds form and the plant grows faster.
It is a natural plant food that the lilac can easily absorb. Fertilizing lilacs is not strictly necessary, except after the first and second year of planting. They can be fertilized with a superphosphate and limestone when planting to sweeten the soil and avoid excessive acidity.
After the first growing season, granular organic fertilizer can be applied to the base of the plant each spring to provide the plant with nutrients for the coming year. The buds are set the previous year so that the fertilizer feeds that year’s leaves and next year’s flower. Lilacs love a sweet soil.
Lilacs should be pruned annually to develop a good stalk and encourage vigorous growth that encourages flowering. Annual pruning consists in cutting diseased, deformed and unproductive stems to the ground. I also thin and remove some stems to encourage vigorous growth at the correct spacing.
For the best shrub care, fertilize with a balanced (10-10-10) fertilizer once in early spring, before new growth appears. NOTE: This is part 4 of a series of 8 articles.
One way to rejuvenate a large, overgrown lilac is to cut the entire plant back to within 6 to 8 inches of the ground in late winter (March or early April). This severe pruning will result in a large number of shoots developing during the growing season.
A. There are several possible reasons why your lilacs are not blooming. The most common cause is lack of adequate sunlight. Lilacs (Syringa) need to be planted in a spot that receives at least six hours of strong, direct sun per day.
Lilac responds best to deep, infrequent watering. Make sure your planting area or container has good drainage. These plants do not like wet feet and will not bloom if overwatered. Too much water can reduce the oxygen in the soil by filling air pockets with water, suffocating the lilac’s roots.
A lilac bush needs at least 6 hours of sun or more to flower optimally. You can move it or cut back the trees that shade it. Be aware that transplanting lilacs can delay flowering for another full year, so be patient. Also, you may need to thin out the bush to ensure sunlight penetrates through the foliage.
A dose of Epsom salts can help the lilac bush bloom.
How to water lilacs. Check plants frequently after planting and water when the top inch of soil becomes dry, usually once or twice a week. Count to 10 when watering to make sure you’re giving each lilac plant enough moisture. (The leaves will begin to droop if the plant becomes too dry.)
When to prune. In general, all lilacs should be pruned immediately after flowering in spring. Because lilacs produce next year’s flower buds just after the current year’s flowers have withered, pruning later in summer or fall will result in many or all of next year’s flowers being cut off.
Individual branches turn brown and die suddenly because the fungi block the branch’s vascular system and interrupt the transport of water and nutrients. Increase watering and fertilizing to extend plant life.
Deadheading is the practice of removing dead buds from a plant by hand. For some plants, this will help stimulate continued flowering. But with lilacs, the only time defoliation seems to help them bloom better is during the first few years of growth. New lilac plants should start blooming within two to five years.
Should lilacs be pruned? No, lilacs should not be cut back to the ground as this will stop flowering. By the end of autumn, the lilac tree in the garden will be little more than a branch. However, it should not be cut back to ground level.
Lilacs are easy to grow. Grow in moist but well-drained, neutral to alkaline soil in full sun. Prune after flowering to keep them from becoming leggy. Mulch annually in spring.
Overwatered lilacs can develop root rot. Yellow, faded, or wilted leaves are a sign that your lilac has been overwatered. If your lilac is overwatered, wait until the soil dries out to a depth of 3-4 inches before watering again.