The common purple lilac is a hardy, dependable shrub that can grow up to 20 feet tall. Unfortunately, the lower, shady sections of lilac shrubs typically lose their leaves as they get older. Large, overgrown specimens as a result are frequently leggy and ugly. Pruning can restore or rejuvenate old, neglected lilacs. Home gardeners have two alternative pruning techniques to pick from.
Cutting the entire plant back to within 6 to 8 inches of the ground in late winter is one method of renewing a huge, overgrown lilac (March or early April). A significant number of shoots will sprout during the growth season as a result of this aggressive pruning. Select a few sturdy, robust shoots to construct the shrub’s framework, keeping a few of them, and cut off all the others at ground level in the late winter of the next year. To promote branching, head (clip) back the retained shoots to just above a bud.
Cutting back the overgrown shrubs over a three-year period is a second method for pruning mature lilacs. In late January, start the process by digging up and removing one-third of the big, old stems. The following year, trim out half of the remaining old stems (again in late winter). Additionally, trim out some of the recent growth. Keep a few healthy stems that are evenly spaced apart and cut off the rest. In the third year’s late winter, completely remove all of the old wood. It is also necessary to thin the fresh shoots more. This pruning technique should enable you to take pleasure in blossoms every spring because lilac wood must be three years or older before it blooms.
Within a few years, with the right pruning, an old, overgrown lilac can be converted into a robust, appealing shrub. Pruning should be a frequent component of the lilacs’ management regimen after they have been revived. By cutting a few of the oldest branches every three to five years, the shrub can be kept strong and healthy.
(This article, which first published in the Sunday edition of the Lincoln Journal Star Newspaper in February 2005, has since been amended. Consult the Terms of Use for details on how to copy this content and use any images or visuals.)
How is a lilac tree revived?
You might believe your lilac is dying if you see it becoming a little frail or worn out, or if it only produces a few little flowers in the spring. Often, all a plant needs to produce robust new growth and abundant, fragrant blossoms is some hard pruning and some feeding. Rejuvenate a lilac bush by working with it just after bloom, when the blooms have dried up and are spent.
To get to the grass or soil layer, rake away any debris, dead branches, or fallen leaves from the lilac’s base.
Pick three to five of the lilac’s strongest branches after surveying the entire plant. Follow the branches you’ve chosen to the plant’s base, where you can flag each sturdy branch by gently tying a rope or ribbon around its base.
Use hand pruners or a handsaw if needed to make a clean, horizontal cut across all of the unflagged branches that are about an inch off the ground. To prevent breaking off any limbs you want to maintain, carefully pull the trimmed branches away from the lilac.
- You might believe your lilac is dying if you see it becoming a little frail or worn out, or if it only produces a few little flowers in the spring.
From the remaining branches, take off your sting or ribbons. Fertilize the lilac around its base according to the dosage and application guidelines provided by the manufacturer.
Mulch should be applied in a ring around the lilac’s base that is no deeper than 3 inches and no wider than 3 feet. New sprouts won’t be able to emerge if the mulch is too deep.
If there is a drought or excessive heat in your area during the summer, make sure the plant is well-watered. Lilacs require good drainage, but they don’t fare well in dry soil.
The next spring, watch for buds to start swelling on the branches. Reapply fertilizer right before flowering and once more after flowering is finished. This is how you should fertilize each year.
- From the remaining branches, take off your sting or ribbons.
- The next spring, watch for buds to start swelling on the branches. Reapply fertilizer right before flowering and once more after flowering is finished.
Maintain your lilac by doing minimal annual pruning to remove wasted flowers and only every three to five years to remove old and dead branches.
Avoid letting the feed come into contact with the branches when applying fertilizer to the area around the plant, whether it be granular or water-soluble.
When should a lilac tree be pruned?
A lilac shrub needs to be pruned every year once it has reached the age of two. Early summer is ideal for cutting grass because the flowers have already flowered and withered. Here are some tips for taking care of lilac shrubs and trees.
Lilacs produce the flower buds for the following season in the early summer, right after their blooms have faded. You run the danger of removing the budding buds if you delay trimming until later in the growing season.
This also holds true for lilacs that bloom twice a year, like Bloomerang Purple. After the bush’s initial bloom, you can prune it to promote new growth and more flowers in the second bloom, which occurs in early fall.
Lilacs eventually only bloom at the tips of their highest branches if allowed to develop naturally. Lilac bushes can be revitalized and made more visually appealing by pruning to maintain a balance between older stems and young blossoming branches.
Pruning a lilac shrub involves a number of techniques:
- First, remove any weaker branches and any dead, broken, or diseased stems. Branches should also be trimmed to avoid rubbing or crossing.
- Old stems that are thicker than two inches should be cut off. This controls the height of your lilac plant and promotes the development of new shoots. It is best to thoroughly remove the stems.
- Control sucker emergence. Suckers are fresh branches that sprout from the plant’s base. The main branches can be replaced by a few robust suckers, but any lesser suckers should be removed at the soil line to prevent them from robbing the plant of nutrients.
Last but not least, here are some general guidelines for pruning lilacs:
- Lilac bushes that are mature should only be pruned to a height of 6 to 8 feet.
- Aim for 10 to 12 primary stems, each of which should be between 1 and 2 inches thick.
- Never remove more than one-third of the bush with pruning.
- Older stems and fresh blossoming shoots should be balanced.
Are lilac bushes capable of regrowth?
- especially when working with plants that exhibit symptoms of illness, clean pruning implements thoroughly. In a dish, combine a 30-percent solution of rubbing alcohol and water or a 10-percent solution of household bleach and water. Tools and blade surfaces should be cleaned between cuts by dipping a clean towel in the solution.
- If you decide to revive your lilac, think about growing it as a shrub as opposed to a tree. In this approach, rather than chopping the shrub down completely, you can regenerate it by removing any dead limbs and pruning a few older limbs by one-third each year. Instead of waiting several years for the lilac to bloom again, you’ll have some bloom each year.
- Lilacs in warmer climates have shorter lifespans than those in regions where winters last for a month or more. Accept the possibility that, if you live in USDA zones 9 or 10, your efforts might not be enough to save your tree.
How can you assist a lilac in need?
Verify that the plant has adequate drainage. Lilacs shouldn’t be overwatered because doing so could cause the plant to drown. Additionally, it’s crucial to avoid submerging the bush because it won’t survive in dry soil. Check the lilac shrub leaves and the soil to see if extra water is required.
Why is my lilac tree not doing well?
Examine the branches for damage like as exit holes and sawdust, sap, and frass, which are indicators of insect infestation. Damage from damaged branches could be stopped by pruning them off. Next spring, as the lilacs begin to bloom, keep an eye out for the adults and place pheromone-activated traps (see Lilac borer).
How come my lilac tree is dying?
- Lilac shrubs die because of a fungus brought on by poorly draining soils. Lilacs need well-draining soil to thrive, and if their roots are in soggy soil, they are vulnerable to root rot and other fungi that can kill the branches and turn the leaves brown.
- If the soil is too dry, newly planted lilac plants may wither and die. For lilacs to flourish, the soil must be evenly moist but also have good drainage. The roots cannot absorb enough moisture if the soil is too dry or too sandy, which causes the leaves to wilt and appear to be dying.
- Lilacs thrive in open spaces with direct sunlight. If the lilac is placed in a shaded garden, it will grow slowly, produce fewer flowers, and its leaves may turn yellow and look to be dying.
- Lilacs are indigenous to the Balkan peninsula and usually flourish in soils with a pH of either neutral or alkaline. The lilacs’ roots cannot absorb some nutrients if the soil is excessively acidic, which results in the leaves turning brown and yellow, poor growth, and a withering appearance.
- Lilacs thrive in cold winter areas with little humidity, and they do best in gardens in USDA zones 3 through 7. In contrast to the conditions to which the lilac has adapted, a winter that is too mild or a climate that is constantly humid leads to fewer blossoms, poor growth, and a higher risk of fungal diseases.
- Lilac borers are insect larvae that manufacture sawdust and make tiny holes in the wood of lilac plants. Lilac borers cause the stems to die and break off, and the leaves to droop.
- Create the conditions of a dying lilac’s natural environment by relocating it to soil that is well-draining but maintains moisture, has an alkaline soil pH, and is in full sun in order to save the lilac. To encourage new growth, prune any decaying branches all the way back to the trunk. Apply lindane spray if there is evidence of lilac borers.
Can you prune a lilac tree firmly?
Regular pruning might simply include any shaping you choose to undertake along with the removal of dead, diseased, or broken stems for any lilac shrubs that have not outgrown their space or are still producing bright flowers every year. You can also prune your lilacs’ spent blossoms to promote a neater growth pattern and appearance. Instead of shearing, it is always preferable to perform this kind of pruning by hand. Try to cut back to a bud that is facing outward while making cuttings. The best instrument for this is a decent set of hand pruners, which provide considerably superior pruning cuts than hedge shears.
How much may a lilac tree be pruned back?
Cutting no more than a third of the stems from a shrub should be the general guideline when pruning it. While a result, the plant will continue to thrive and grow new stems as the old ones bloom. Your aim is to grow a lilac bush with between eight and twelve stems, all between one and two inches in diameter, and of varying ages.
Prune Unsightly Features
Pruning should start with the removal of diseased, dead, and pencil-thin suckers and twiggy growth. Trim these all the way to the ground. These stems are typically handled by pruning shears or loppers.
Remove Any Stems Thicker Than 2 Inches in Diameter
By routinely removing entire old stems, you can keep your lilac from growing too tall. Removing only the tops of lengthy stems might cause the plant to take on an unusual, unnatural shape. A pruning saw could be essential for stems that are quite large. It can be difficult to handle thick lilac stalks.
Prune Remaining New Stems
Pruning the remaining new stems to an outward-facing bud will encourage your lilac to fill out more and develop a shrubby appearance. This entails trimming just past buds that point away from the plant’s core. A denser shrub will result from this technique’s increased branching.
How should a mature lilac tree be pruned?
Similar to the lilac, heavy pruning needs to be done over a number of years. Remove any dead, spindly, dying, or ill-looking wood first. At the base, remove roughly a third of the tallest, oldest branches. The remaining branches should then be cut back by at least a foot. Over the following two years, repeat the same action.
Azaleas and rhododendrons prefer somewhat acidic soils. The optimal time to fertilize in the spring is right after flowering. Though slightly more expensive than chemical fertilizers, organic fertilizers release their nutrients gradually and require less frequent application. After July 15, refrain from fertilizing to prevent the plant from going into full dormancy before winter. Use of lime or alkaline fertilizers should be avoided.
In the summer, rhododendrons and azaleas require a lot of water due to their shallow, fibrous root systems. Make careful to thoroughly hydrate them. You will require water all year long if they are planted beneath wide eave overhangs. Avoid going too deep when hoeing or raking around the plants. Mulches can be used to control weeds, maintain more consistent soil temperatures, and save moisture. Examples of such mulches include sawdust, bark dust, peat moss, straw, or other organic materials.
The garden is busy at the moment. These days, your vegetable garden can contain just about anything. Don’t put it off! Plant more lettuce, carrots, beets, potatoes, peas, cucumbers, squash, pumpkins, melons, dill, basil seedlings, and brassicas. Also plant more beans, tomato and pepper plants, and more lettuce.
Which fertilizer is ideal for lilac trees?
Lilac plants don’t require a lot of food or fertilizer. A 10-10-10 fertilizer mixture applied yearly in the early spring is what we advise. (The amounts of nitrogen, phosphorus, and potassium, or NPK as they are popularly known, are represented by the digits 10-10-10 in the formula.) Early spring fertilization of lilacs with a high phosphorus solution encourages blossoming.
Coffee grounds and grass clippings are also excellent sources of nitrogen. Use in moderation since an excess of nitrogen in the soil can lead to subpar blooms. The ideal soil conditions for lilacs are slightly alkaline (6.5–7.0 pH), wet, and well-drained. The soil may become more alkaline by adding bone meal to it. Use Miracle-Gro Shake ‘n Feed Flowering Trees & Shrubs Plant Food in the spring if you decide to feed your plant. Last but not least, lilac plants dislike acidic soil. Epsom salts can be used to encourage blossoming while the plant is dormant.