Growing Lilacs: A Beginner’s Guide to Planting, Caring, and Pruning

Lilacs are the quintessential harbingers of spring! These delightful shrubs are not only low-maintenance but also burst into bloom with a sweet, captivating fragrance that perfumes the air. Let’s dive into planting, growing, and pruning lilacs to keep them thriving in your garden.

Symbolizing youthful joy and the revival of spring, lilacs are robust and easy to care for. They vary in height, typically growing between 5 to 15 feet, allowing their fragrant blossoms to be perfectly positioned at nose level, making it easy to appreciate their lovely aroma.

About Lilacs

Lilacs, or Syringa, are a delightful addition to any garden, belonging to the Oleaceae or olive family. Originating from Europe and Asia, there are roughly 20 species of these enchanting shrubs and small trees.

Known for their fragrant, colorful flowers ranging from purple to pink and white, lilacs bloom from late spring into early summer. These blooms not only add a splash of color but are also perfect for creating stunning floral arrangements and are even edible!

The most popular variety, Syringa vulgaris, also known as the common lilac, was once a staple in Edwardian gardens and has seen a resurgence in popularity due to its hardiness and aromatic flowers.

It’s a plant that not only brings beauty with its blooms but also attracts butterflies with its scent. Impressively, lilacs are hardy plants that can live for over a century, often outlasting the very buildings they were planted near.

In northern regions, lilacs typically display their blooms for about two weeks during mid-to-late spring. However, by planting early-, mid-, and late-blooming varieties together, you can enjoy a continuous display of flowers for up to six weeks.

These plants are versatile in size and form, ranging from compact shrubs perfect for small spaces to larger trees that make a statement in your garden. Their heart-shaped leaves and varied bark textures add further interest.

For garden enthusiasts looking to enhance their landscape, lilacs offer an array of options. You can choose from dwarf varieties for tight spaces or majestic specimens ideal for larger areas or as a focal point in a mixed border.

To further extend their season of interest, consider intertwining a late-blooming clematis with one of the larger lilac varieties. This not only prolongs the garden’s charm but also maximizes space, bringing lush, vibrant growth throughout the gardening season.

When and Where To Plant Lilacs

First and foremost, lilacs need fertile, well-draining soil with a touch of humus. Aim for a neutral to slightly alkaline pH, around 7.0. If your garden soil seems lacking, don’t hesitate to work in some compost to give it a boost.

• Choosing the right spot is crucial.

Lilacs hate having “wet feet,” which is gardener-speak for soil that stays soggy and can lead to root rot. To avoid this, pick a place where water doesn’t linger. Conduct a quick drainage test by digging a hole about 8 inches across and 12 inches deep, filling it with water, and if it hasn’t cleared in an hour, you might want to scout out a new location.

• Sunlight is a non-negotiable for lilacs.

These beauties need at least six hours of direct sun each day to put on their best floral display. Less light means fewer blooms. When planting, consider how big they’ll get. Lilacs come in all sizes, from charming dwarf varieties to towering tree lilacs that can reach up to 30 feet.

Check the plant label for the specifics on height and spread to ensure you give them enough room to spread their roots. The best time to plant is either spring or fall, but fall is often better, giving them plenty of time to establish before the summer heat.

Remember, whether you’re dotting your yard with a single lilac or creating a privacy hedge, these hardy shrubs prefer cooler climates and thrive under the right conditions. So, get your garden gloves ready, and let’s make your lilac dreams come true!

How To Plant Lilacs

You can start planting lilacs in the spring as soon as the soil thaws or during autumn before it freezes over. Typically, lilacs arrive dormant during spring, often as bare-root plants. They’re not dead, just in a resting phase.

When your lilacs arrive, first remove any packaging around the roots and soak them in lukewarm water for about 10 to 15 minutes. Alternatively, you might pick up potted lilacs from your local garden center.

Sometimes, you might get a lilac sucker from a friend or neighbor. These offshoots from the main plant might look unimpressive at first. Just plant the sucker in a prepared hole, refill it with soil, and give it some water. Be patient — in about four to five years, you’ll enjoy large, aromatic flowers.

Planting lilacs from a nursery is straightforward too. For those in containers, gently loosen and spread the roots as you place them in the earth. If they come with a burlap cover or in a balled form, remove any fabric and ties before planting. Position the plant slightly deeper than it was in the nursery, about 2 to 3 inches, and surround it with topsoil before watering.

When planting several lilac bushes, space them anywhere from 5 to 15 feet apart, depending on their mature size. Dig a spacious hole, set your lilac level with the ground, and press the soil down around the roots. After planting, water it thoroughly and apply a layer of mulch to help the soil retain moisture.

For potted lilacs, ensure the pot is at least 60cm wide. When transplanting, dig a hole twice the width of the container and a bit deeper. Set the root ball in, fan out the roots, and refill with the soil you removed. Add mulch around the base and water generously.

Remember, the distance between plants will depend on the lilac variety, ranging from 5 feet for smaller types to 15 feet for the larger ones. Here’s a quick recap for a successful planting:

1. Ensure the planting hole is wide and deep enough for the roots to spread.
2. Align the top of the root ball with the ground level; bury the top layer of a bare-root a few inches under.
3. Backfill with soil from the site and water gradually to avoid air gaps, ensuring the soil fits snugly.
4. For the first few years, water your lilacs regularly, especially during dry spells. Once they’re established, they generally thrive with just the natural rainfall.

How to Care for Lilac Bushes

Spring is the ideal time to refresh your lilac bushes with a new layer of mulch, helping them stay lush and vibrant. As the blooms start to fade in summer, consider deadheading the smaller varieties to keep them looking tidy.

The best time for pruning is right after the flowering season ends. Trim the bushes to shape them and control their height, removing any dead or unhealthy branches.

If you have an overgrown or aged lilac, winter is the opportune moment for a major pruning when the plant is dormant. You can cut it back drastically to about 1 meter above the ground level.

However, be aware that this severe pruning may prevent blooming for the following year. For a gentler approach, gradually remove stems over two to three years, allowing you to enjoy some flowers each spring.

• Sun Exposure and Shade Tolerance

Lilacs thrive in full sun, which encourages abundant blooming. While common lilac varieties can tolerate partial shade, their flowering will be less prolific, and they may develop powdery mildew—a common issue in shadier spots.

• Soil Conditions and Watering

Kick off the growing season by enriching the soil around your lilacs with compost, followed by a fresh layer of mulch to retain moisture and suppress weeds. During dry spells in summer, water your lilacs if weekly rainfall is less than an inch.

Choose a planting site with well-draining soil that leans towards a neutral or slightly alkaline pH. Once established, lilacs are quite drought-tolerant.

• Climate Considerations

Lilacs are robust shrubs that can grow in cooler climates, even as chilly as Zone 2. However, be wary of early spring warm spells followed by frosts, which can damage the pre-formed flower buds. These shrubs are less suited to very warm or humid climates above Zone 8 due to the high risk of powdery mildew.

• Fertilizing for Healthy Growth

After the initial growing season, feed your lilacs with an organic granular fertilizer each spring to nourish the current and next year’s growth. Lilacs prefer less acidic or “sweet” soil, so consider adding garden lime in the fall if your soil is on the acidic side.

Use a balanced (10-10-10) slow-release fertilizer in early spring before new growth emerges, but be careful not to over-fertilize, as excessive nutrients can inhibit blooming.

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• Post-Bloom Care

Once your lilac has finished blooming, enhance the soil around the base with lime and well-rotted manure, and prune the bush to maintain its shape and remove any unwanted suckers.

• Container Planting for Dwarf Lilacs

While most lilac varieties are too large for containers, dwarf lilacs can thrive in pots. Choose a sturdy container like terra-cotta with good drainage. Mix potting soil with compost for the best growing conditions, and remember that potted lilacs need more frequent watering than those planted in the ground.

• Deadheading for Reblooming Varieties

For lilac varieties like ‘Josée’ that bloom more than once per season, deadheading is crucial as it encourages further flowering. For other types, while not necessary, deadheading helps keep your lilac looking neat and tidy.

How to Prune Lilacs

Pruning your lilac bush is key to improving air circulation and promoting healthy growth. The best time to prune lilacs is right after their blossoming period in spring since they flower on old wood. You can remove any dead, diseased, or broken branches throughout the year without following a specific schedule.

Although lilacs don’t require annual pruning, trimming off the old flower heads shortly after they bloom can redirect the plant’s energy toward producing more buds instead of seeds.

For lilacs that are becoming too tall or not blooming as much, rejuvenate your shrub by cutting back one-third of the oldest branches each year, reducing them to about 12 to 15 inches above the ground. This encourages new growth. Spread this pruning over three years to revitalize your lilac without losing too many flowers.

Here’s a quick guide to keep in mind:

• Prune right after the lilacs bloom to avoid cutting away next year’s blooms.
• Annually, remove any dead branches and trim the oldest canes down to the ground. Remove smaller suckers and shorten weak branches to a stronger shoot, adjusting tall canes to around eye level.
• Ideally, a healthy lilac should have about ten canes. If your shrub is old and overgrown, consider removing a third of the oldest canes in the first year, half of the remaining old wood in the second year, and the rest in the third. Alternatively, you could cut the entire plant back to about 6 to 8 inches from the ground. Though this drastic method results in a few years without blooms, it’s a less labor-intensive approach that leads to a robust regrowth filled with flowers.
• Remember, heavy pruning might mean waiting one to three years for new blooms, so it’s wise to keep your pruning moderate and regular.

As the revered 19th-century English horticulturist Gertrude Jekyll once advised, it’s more effective to pull out suckers than to cut them. Tearing them away helps remove the part of the root that can regrow, ensuring they don’t come back easily.

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Pests and Challenges

Lilacs are generally hardy and resistant to pests and diseases, making them a delight for gardeners. However, they are not entirely immune to issues.

One occasional problem is powdery mildew, a fungal disease that appears as a white coating, primarily during the humid months of mid-to-late summer. While it mars the plant’s appearance, it is harmless and often best left untreated.

• Slugs and snails may target the plant.
• Warm, moist weather increases the likelihood of the unsightly white powdery mildew film. It is an eyesore but typically causes no real damage.

Despite their hardiness, lilacs can sometimes fall prey to pests like leaf mining moths and thrips. Fortunately, these pests rarely weaken the plant significantly.

Inadequate blooming in spring might result from poorly draining soil or lack of sunlight—lilacs thrive in sunny locations. Additionally, unexpected late frosts can damage the blooms.

Suckers often emerge from the plant’s base. If you prefer not to use these for propagation, it’s better to pull or twist them off rather than cut them. This discourages regrowth and is best done from midsummer onward.

Lilac blight is another concern, leading to leaf discoloration, deformity, and drop, and even affecting blossoms, causing them to turn brown and wilt. To combat this, prune the infected branches thoroughly, particularly in dry, sunny conditions to enhance air flow and check further spread.

Lilac Varieties for Your Garden

If you’re looking to add timeless elegance to your garden, consider cultivating some lilac varieties. Here’s an overview of popular choices:

• Common Lilac

Known for its enchanting fragrance, the Common Lilac (Syringa vulgaris) is a favorite in many gardens. Originating from Europe, early settlers brought this deciduous shrub to America, charmed by its delightful scent. It grows to heights of 8-12 feet and spreads 6-10 feet wide.

The Common Lilac features dark green leaves and boasts purple blooms against brownish-gray bark. It’s perfect for standalone spots or as part of hedges, screens, or borders. Its numerous cultivars offer an array of colors, from purple and lavender to magenta and white.

• Dwarf Lilac

For those with limited space, Dwarf Lilacs provide the same lovely hues and aromas in a more compact form. These varieties generally grow between 4 and 6 feet tall and are ideal for smaller gardens or container planting. They require less maintenance and can be shaped into neat hedges or topiaries.

The Meyer Lilac, a well-known dwarf type, reaches about 4 feet in height and produces vibrant dark violet flowers. Some even display stunning autumnal foliage in vivid oranges and yellows.

• Japanese Lilac

The Japanese Tree Lilac is a larger species, reaching 20 to 30 feet in height, making it an excellent choice for street borders or as a natural privacy screen. It blooms slightly later in the season, showcasing creamy-white flowers that attract butterflies and hummingbirds. The peeling reddish-brown bark of this lilac adds winter interest to your garden landscape.

• Specialty Cultivars

Several unique lilac varieties also deserve a mention. The ‘Angel White’ Lilac, with its large, fragrant white blooms, is particularly heat-tolerant. Meanwhile, the Bloomerang Lilac reflowers from midsummer to fall, providing extended beauty and fragrance.

For compact spaces, the ‘Miss Kim’ and Dwarf Korean Lilacs are excellent choices, blooming profusely with lavender-pink flowers.

• Notable Mentions

The ‘Edith Cavell’ and ‘Frederick Law Olmstead’ lilacs boast large, white blooms, perfect for a striking spring display. Cultivars like ‘George Eastman’ and ‘Mount Baker’ offer unique flower forms and colors, enhancing the diversity of your lilac collection.

Frequently Asked Questions

• What is the nature of lilacs: trees or shrubs?

While some types of lilacs, such as the Japanese tree lilac, may resemble trees, they are typically categorized as shrubs or bushes. With pruning, you can shape them to either spread out as a bush with multiple branches or stand tall like a tree with one main stem.

• Are lilacs originally from North America?

Lilacs originate from eastern Europe and temperate Asia, not North America. Early settlers brought them over, and since then, lilacs have become a staple in American gardens for hundreds of years.

• Should lilacs be covered during winter?

Lilacs are quite resilient and generally do not require protection in the winter, even in extremely cold climates. However, sudden temperature shifts during the winter, such as a brief warm period followed by a severe drop, can harm their flower buds.

To minimize this risk, consider planting lilacs in a location shielded from harsh winter winds, like the southern side of a building.

• What do lilac colors signify?

Each color of lilac has its unique symbolism. White lilacs are associated with purity and innocence, while purple ones are linked to spirituality. Blue-tinted lilacs denote happiness and peace. Magenta lilacs are a symbol of love and passion. Yellow lilacs, a relatively recent addition since 1949, do not carry a specific symbolic meaning.

• Can you eat lilac flowers?

Yes, lilac flowers are edible, though their taste can vary significantly between different varieties, ranging from bland to subtly citrusy. For the best culinary use, pick healthy, vibrant blooms early in the day. Ensure they are free from pests and diseases. Rinse them carefully in cool water, pat them dry, and keep them chilled until use.

For a delightful twist, try creating candied lilac petals: gently coat each petal in egg white, then dip them in fine sugar and let them dry. These make exquisite toppings for cakes.

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