How to Grow Common Lilac Flowering Shrubs

flowering lilac bush shrub

by Jennifer Poindexter

Picking shrubbery can be one of the most difficult parts of planning a landscape. The reason being, it’s not like a flower.

Flowers come and go. Many are annuals, so if you don’t like the way they look, you plant something different the next year.

Shrubs are a little more permanent. This is why you might want to consider planting common lilac. It’s also known as French lilac.

This shrub comes in a variety of colors and is one of the most aromatic types of lilac. If colorful and fragrant sounds good to you, here’s what you must know to grow common lilac successfully.

Growing Conditions for Common Lilac Bush

When choosing a shrub to grow, it doesn’t get much easier than the common lilac. Provide a few basic growing conditions, and your shrub should have a good foundation for success.

To begin, be mindful of where you plant common lilac. This shrub can grow to be 15 feet in height or taller.

Obviously, this wouldn’t be something you’d want to grow right across the front of your home, depending upon the variety.

As mentioned previously, there are many varieties of common lilac which also come in multiple colors. Be sure you know which variety you’re purchasing to understand it’s height and where it would look best on your property.

After you’ve established a suitable place for the plant to grow, ensure this location receives full sun and has well-draining soil which remains consistently damp.

If there’s no sun shining on this shrub you won’t receive as many blooms. The other big factors in a proper grow space are planting at the right time and checking the soil’s pH.

Plant common lilac in the fall, prior to the ground freezing, or in the spring as the soil becomes workable again.

I’m not usually one who harps on soil pH levels but when growing common lilac, it matters. It prefers alkaline soil with a pH between 6.5 and 7.0.

If you need to increase your soil’s alkalinity, add lime. Don’t plant until you’ve got the soil where it needs to be.

By taking the time to make sure each of these requirements are met, you’re giving common lilac an opportunity to prosper.

How to Plant Common Lilac

Planting common lilac is as basic as it comes. There’s no fancy instructions. You’ll begin by finding an appropriate grow space.

Once located, dig a hole that’s twice the width of the plant but at the same depth as the plant. You want the common lilac to be snug in the hole.

Cover the roots up with the soil you unearthed. When the roots are covered, it’s important to water the plant heavily to provide the desired moist soil.

When you’ve finished planting, add mulch around the bush to maintain the necessary moisture level.

After you’ve planted a mature common lilac bush, allow it to become established. This will provide cuttings, so you can propagate more plants without spending additional money.

Wait until the following year when new growth forms on the plant and cut a few pieces from it. Each cutting should be approximately a half foot in length.

Remove all the leaves of the cutting at the bottom. Leave the remaining leaves at the top of the cutting. Fill a pot with sand, dip the cutting in rooting hormone, and place it in the pot.

The cuttings require warmth but aren’t particular about lighting. You can leave them on top of your fridge or in a warm greenhouse. Ensure the sand remains moist. It should take the cuttings a month or more to form roots.

When the roots are formed, the new plants are ready for transplant. Common lilac can be difficult to propagate at times, so if you don’t have great success at first, keep trying.

Remember, the more cuttings you use, the greater chance you have at being successful when propagating common lilac. 

Caring for Common Lilac

There are only four things you must do as the gardener of a common lilac bush. They need to be watered correctly, deadheaded, pruned, and fertilized.

To water common lilac correctly, it’s important to use the deep watering method. Water one to two times per week for longer periods of time. This ensures the water reaches the plant’s root system.

If unsure about when to water your common lilac, try the knuckle test. Insert your finger into the soil next to the plant. If it’s dry to the first knuckle, it’s time to water. If not, hold off for a day or two longer.

Only do this during the first month, after transplant, while the roots are still establishing themselves. After the first month, switch to deep watering every couple of weeks.

Continue with this through the first year. After year one, the shrubs are on their own. Unless going through a period of drought, the lilac should be fine without additional water from you.

The next thing you must do when caring for common lilac is deadhead the shrub. When the old blooms are spent, gently pluck them off. This will encourage new growth on the plant.

Common lilac should be pruned in the spring after blooming has ended. Unlike many shrubs, this plant blooms from the older portions, so you don’t want to prune prematurely.

Therefore, you’ll want to cut the plant back by a quarter of its original size once blooming has ended. Don’t prune too heavily, or it may not bloom for a few years.

Light pruning is enough to keep the plant healthy and to encourage it to continue to bloom year after year.

Finally, fertilizing is the last need this plant has. Fertilizing common lilac is simple. The plant only should be fertilized one time during the winter months. If you over fertilize, the plant won’t bloom.

Common lilac can be a gardener’s dream when it comes to necessary care because of its independence.

Garden Pests and Diseases for Common Lilac

There are only a few pests and diseases gardeners should be aware of when it comes to growing common lilac.

The only disease which commonly draws to this shrub is powdery mildew. You can combat this by choosing varieties which are resistant to it, or you can ensure there’s proper airflow surrounding the plant.

If powdery mildew appears, be sure to remove any damaged part of the plant and treat with a fungicide.

Slugs and snails are typical pests which visit common lilac. They can be treated by handpicking them if you see any moving around your plant. They’re usually spotted at dusk. 

However, if you prefer to avoid touching the pests, you can always spread coffee grounds or diatomaceous earth on the ground around the plant.

Snails and slugs don’t like the caffeine in the coffee, and it serves as a natural repellent. DE creates a dangerous area for the snails or slugs to crawl over.

Not only is common lilac easy to plant and care for, but it also has few enemies in this world. This should make your life easier when growing this bush.

Most gardeners love easy plants. Common lilac seemingly falls into this category. It’s independent and prefers to be left alone the majority of the time.

Yet, this shrub provides gorgeous blooms for your landscape and also provides a nice scent wherever it grows. If you could use this type of beauty in your life, consider growing the common lilac bush.

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