How to Grow and Prune Lilac Bushes
Growing Lilac Bushes in Your Garden
Lilac bushes are one of the easiest plants to grow in your garden, even if you have poor soil. They are almost indestructible and they will provide shade and fragrant flowers for decades with proper care. These bushes can be used as a hedge or as a single plant that adds interest to the garden. The lilac bush blooms each spring with a profusion of flowers and can be grown with ease in zones 3–8. If you're looking for a versatile landscaping bush that requires little care, this may be the perfect plant for you.
How to Choose What Lilacs to Plant
You've decided to try growing one or several lilac bushes in your garden, but you don't know how to choose the right one. The answer is fairly simple—choose the color or colors that you admire the most. The different types of lilacs, whether new or old-fashioned varieties, will all grow in the same areas. The only discernible differences are the colors and strength of fragrance.
How to Plant Lilac Bushes
Planting seedling lilac bushes is very easy to do. The plants are relatively small, making them a snap to dig a hole for. They can be found as bare rootstock or in pots at many nurseries.
- Dig a hole twice as wide as the root ball, or at least 5 inches in diameter if you're planting small, bare root stock.
- Amend the soil so that it is well-aerated. Even though these plants will grow in virtually any soil, consider adding a small amount of sand, peat moss, or compost to aid with aeration, help retain moisture, and add nutrients to the soil.
- If the plant has a root ball, form a small mound in the bottom of the hole and gently spread out the roots of the plant.
- Gently replace the amended soil around the roots, tamping it lightly back into place. Bare root stock can simply be held in place while you add the soil back into the hole, gently tamping the soil until the plant can stand upright by itself.
- Water the plant, keeping it moist during the growing season, especially if you live in a hot, dry climate. It should be well established by the spring of next year with proper care.
How to Prune Lilacs
Depending upon where you live, you may choose whether to prune back your lilac bush or simply let it go unattended. Many rural farm houses have lilac bushes around them that are simply let go once they are established. Lilac bushes can reach heights of up to 12 feet if they aren't pruned.
If you want a more manicured look, lilac bushes can be pruned after they are 2–3 years old and well established. The bush naturally has a vase shape, with the new growth each year in a clump at the base of the plant with the upper growth fanning out in all directions, like a vase full of wild flowers.
The plant can be pruned in several ways to keep it in check and to keep it from spreading. New shoots will appear at the base of the plant each year. You should prune these shoots back to the ground or dig them up to transplant them elsewhere if you don't want new plant growth. Do this as soon as the new growth appears.
Next, the branches can be pruned at the end of the leaders (main stems) to halt the outward growth. If you want the plant to have more growth upwards, prune off the growth that is starting to grow downwards, leaving the new upward growing shoots on each leader.
Finally, check the growth on the top of the bush. Prune back the main stems if you want to keep the upward growth in check.
Each year you should also remove any deadwood. As the plant ages, the amount of dead wood will increase and create a visual hole in the center of your bush. Allow some new shoots to fill this hole in the spring to replace the old, dead wood. This will help your bush maintain the vase-shaped appearance.
A general rule of thumb for well-established lilac bush is to prune back ¼ of the new growth each year, right after the bush is done blooming. If you prune much later than this, you will prune away the new bud growth and may have few, if any, new blooms the next spring.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Questions & Answers
What kind fertilizer should I use to grow lilacs?
I use store bought manure from our local garden center - usually every other year works fine for my bushes. While you may also use bush fertilizer stakes, make sure to follow the directions for placement. They can "burn" your bushes if you place them too close to the bush, or use too many.Helpful 3
How quickly do lilac bushes grow?
Lilac bushes can grow up to a few inches per year, depending on weather conditions. It is very wet and rainy here in NY in the spring, followed by variable dry and wet periods throughout the summer. The plants are very drought tolerant here, but they don't like being wet constantly.
If you can provide moderate watering when needed and can keep wildlife away from "baby" plants, your lilacs should continue growing a few inches each year, possibly more if you are in a warmer climate than NY.Helpful 2
We have two, well-established six-foot tall lilac bushes. They are beginning to bud. When is the best time to trim them?
Trim the plants after they are done blooming. They begin to form buds for the following year towards the end of the summer. If you wait too long to trim them back, you may not have any blooms the next year because you'll have trimmed off the buds.
© 2009 Charlotte Gerber