Lilac Bush: The Ultimate Growing Guide (Beginners To Advanced)

Lilacs are among the most beloved and fragrant flowers, with enchanting blooms and sweet scents that can fill any garden and soul with beauty and meaning. Some may wonder, but what do lilacs symbolize?

In the language of flowers, lilac meaning defines youth’s joy, spring’s freshness, and first times. From the botanical perspective, lilac flowers attract butterflies, making them perfect to design a vibrant landscape.

Person holding lilac flowers Image credits: Valeria Boltneva

Lilacs belong to the genus Syringa, including 25 known species, native to eastern Europe and temperate Asia, according to Britannica. The common lilacs have four-petaled purple flower clusters, which can also come in pale blue, light purple, pinkish, or white.

Are you considering lilacs for your garden, but doubting how much you know about growing them? Whether you’re a beginner or an advanced gardener, this ultimate guide will provide all the answers on how to grow and care for lilacs. So grab your gardening tools and create your own lilac paradise!

Table with information about lilac

Where Do Lilacs Grow Best

Lilac bushes on the background of the sky Image credits: Irina Iriser

Climate

Lilacs thrive in climates that have relatively cool summers and cold winters. They are resistant in zone 2 but hardy in zones 3 to 7.

Soil

Lilacs love rich, loamy, neutral (pH of 7.0) to slightly alkaline (pH of 7.4–7.8) soil and sharp drainage. You can use compost to adjust your soil pH.

Orientation

Lilacs grow best planted in full sun, meaning they should get at least six hours of direct sunlight on most days. Given less, they won’t flower as well. Lilacs don’t do well in full shade, so it’s best to find them a sunny, south-facing spot.

When and How to Plant Lilac Bush

a white picket fence with lilac flowers on it Image credits: Anna Shipman

Best Time for Planting and Replanting

Lilac shrubs should be planted in the early fall before the ground freezes or in the early spring after the last frost. The best time to replant lilacs is in the early spring, after they finish flowering and before the summer heat sets in.

Planting Methods

Dig a hole deep and wide enough to accommodate the roots of the lilac and set the plant 2 to 3 in (5 to 7.6 cm) deeper than it grew in the nursery. Depending on the variety and desired effect, lilacs should be placed 5 to 15 ft apart (1.5 to 4.5 m). After planting, water the lilacs well and mulch them to retain moisture and control weeds.

How to Care for Lilacs

Are lilac bushes hard to grow? Fortunately, lilacs are generally easy to cultivate. Still, they do require specific growing conditions and care. If you want your lilac to thrive and bloom well, follow these simple steps, covering everything from watering to propagating.

Watering

illustration about watering a lilac

Lilacs need well-draining soil and regular watering, especially during the first growing season and hot summers.

Water every 10 to 14 days or when the top inch of soil feels dry.
Water slowly and deeply. Moisten the soil to a depth of 12 in (30.5 cm).
Retain moisture by mulching around the base of the lilac bush. This also helps prevent weeds.
Reduce watering after flowering and before dormancy. Water your lilac less after it blooms, and only provide water during extended dry spells to prevent root rot. Moreover, reduce watering in fall as lilac prepares for dormancy.

Temperature & Humidity

Two water cans near the bushes in the yard Image credits: Anya Chernik

As lilacs prefer climates with cold winters and cool, though sunny summers, the best temperature is between 65°F and 76°F (18.3°C and 24.4°C). Lilacs also can withstand freezing temperatures. However, they do need protection from frosty cold winds.

Hot and humid regions such as the Southern United States aren’t suitable, as humidity can lead to fungal diseases.

Fertilizing

a person shoveling the soil Image credits: Greta Hoffman

Lilacs are spring-feeding shrubs that greatly benefit from regular fertilization, especially in poor soils or during the first growing seasons. Regular fertilization helps them produce larger flowers, healthier foliage, and stronger roots.

The best time to fertilize lilacs is in early spring, just before they leaf out. For fertilizing lilacs, you can use organic material, bone meal, fish meal, and compost or buy liquid, powdery, or granulated fertilizer. Opt for a balanced fertilizer specifically formulated for lilac shrubs (for example, 10-10-10 or 20-20-20).

Quick tip: Don’t overdo it. Over-fertilization can cause excessive leaf growth and poor blooming. Also, avoid fertilizers high in nitrogen, as this can make the soil too acidic for lilacs.

Blooming

Purple lilac flowers with green leaves Image credits: Karo K.

Many may be wondering, what month do lilacs bloom? Lilacs are spring-flowering shrubs that bloom for a few weeks, usually from mid to late May, depending on the climate and variety.

However, there are early, mid, and late-season lilacs, which can extend the blooming season to six weeks or more. You can also choose reblooming lilacs, which flower again in midsummer and fall.

Quick tip: While blooming, water the plant deeply and regularly, especially during dry spells.

Pruning

Illustration of pruning a lilac

Lilacs bloom on old wood, which means that the flower buds for the next spring develop on growth from the previous year. As a result, the best time to prune lilacs is immediately after blooming before they start forming new buds.

If you prune your lilacs in late summer, fall, or winter, you will remove the flower buds formed on the old wood and reduce the blooming for the next season.

Quick tip: Hard pruning can stimulate growth in overgrown, old, or poorly flowering lilacs. However, keep in mind that it will reduce or eliminate flowers for at least one year.

Propagating

illustration of a lilac propagating

Lilacs can be propagated from shoots, cuttings, or seeds. However, propagating from shoots is the easiest and most successful method. Shoots are new stems that grow from the roots of existing lilac bushes. They usually appear in late spring or early summer after the lilacs have bloomed. So, how do we propagate from them?

Locate the shoots near the plant base. They will look like small, green stems with leaves at the end.
Cut the shoot from the plant. Use a sharp shovel, and make sure to include some roots.
Dig a hole. Pick a sunny spot with well-drained soil, and plant the shoot at the same depth.
Water. After planting, the shoot requires watering and moisture until it becomes established.

And there you have it, enjoy your new lilac plant!

Common Lilac Problems

Lilac shrubs are usually trouble-free. However, they may experience a few common problems, such as poor flowering, heat intolerance, and poor aging. Here are things that cause these issues and ways to solve them.

Low Flowering

A sick bush of lilac in the yard Image credits: P_Kordus

Low flowering can be caused by improper pruning, too much nitrogen fertilizer, insufficient sunlight, or warmer winters.

Solution: Prune lilacs right after they flower, use a balanced fertilizer, plant them in a sunny spot, and choose varieties adapted to your climate.

Heat Intolerance

A bush of purple lilacs in a garden Image credits: Mykyta Kondratov

As lilacs prefer cooler climates, they are less tolerate of heat. Excessive summer heat can cause wilting, shriveling, and premature leaf drop. Lilacs under heat stress may not produce flowers and could become more susceptible to pests and diseases.

Solution: Avoid planting lilacs near sources of reflected heat or limited airflow, such as walls, pavements, or solid fencing. Choose varieties adapted to your climate and provide adequate water and mulch.

Poor Aging

The lilac tree without leaves Image credits: Burnmaxx2077

Lilacs can become bare-bottomed or leggy with age and often look bedraggled with leaf infections after a hot summer. If the old wood isn’t pruned, the plant can produce fewer and smaller flowers.

Solution: Right after spring flowering, prune lilacs to remove about one-third of the oldest and thickest stems at the base. This will stimulate new growth and more blooms.

Common Pests & Plant Diseases

The lilac bush with dry flowers on it Image credits: NYCNark

According to the University of Maryland, there are three most common lilac diseases: bacterial blight, fungal leave spots, and powdery mildew.

Bacterial Blight

The bacterial blight is caused by the bacterium Pseudomonas syringae cv. syringae that live on leaf surfaces. The disease causes blackening of new shoots, leaves, and flower buds, as well as dark spots on leaves with yellow halos. It spreads quickly and can kill entire shoots.

Solution: The disease is favored by rainy spring weather, so avoid overhead irrigation and prune only in dry weather. Remove infected plant parts immediately to prevent further spread. Apply copper-based fungicides or bactericides to protect healthy plants.

Fungal Leaf Spots

Fungal leaf spots are caused by fungi that infect the leaves of lilacs, especially when wet or humid. They appear as brown or black spots on the leaves and may cause them to fall off prematurely.

Solution: No treatment may be applied as fungal spots aren’t life-threatening to lilacs. However, the best way to prevent and control fungal leaf spots is to prune off the infected leaves and twigs and dispose of them properly.

Powdery Mildew

Powdery mildew is caused by fungi that grow on the surfaces of lilac leaves, stems, and shoots, forming a white powdery coating. This coating blocks the light needed for photosynthesis and reduces the plant’s vigor. The fungus thrives in warm and humid conditions, especially at night.

Solution: Select resistant cultivars and plant them in full sun. Also, avoid crowding the plants and prune them regularly to improve air circulation and remove infected parts.

Popular Lilac Varieties

Syringa vulgaris, or the common lilac, is the most widely grown and cultivated species and the parent of many popular varieties. However, there are more lilac varieties within the Syringa genus. Let’s meet seven of the most common ones.

‘Beauty of Moscow’ Lilac

Buy Beauty of Moscow

Image credits: Jonathan Cooper

Syringa vulgaris ‘Beauty of Moscow’ is a French hybrid lilac that has double pink buds that turn into white flowers. It loves full sun and blooms in late spring, spreading a strong fragrance. It can grow up to 12 ft tall (3.6 m) and 7 ft wide (2.1 m).

‘Sensation’ Lilac

Sensation Lilac

Buy Sensation

Syringa vulgaris ‘Sensation’ is another French hybrid lilac, yet this one has unique bicolor flowers. The petals are purple with a white edge, creating a striking contrast. It also has a strong fragrance, prefers full sun, and blooms in mid-to-late spring. Sensation cultivars can grow to 10 ft tall (3 m) and 12 ft wide (3.6 m).

‘Miss Kim’ Lilac

Miss Kim lilac

Buy Miss Kim

This Korean lilac has lavender flowers that fade to pale purple. It blooms later than most lilacs, extending the flowering season from late spring to early summer, and has a spicy fragrance. The shrub prefers full or partial sun and typically reaches a height and width of 6 to 8 ft (1.8 to 2.4 m).

‘Bloomerang’ Lilac

Bloomerang lilac

Buy Bloomerang

Named for its blooming pattern, the Bloomerang lilac bush blooms in spring and then reblooms in summer and fall. It thrives in full sun, has lavender-pink flowers, and a sweet scent. This compact lilac grows up to 5 ft tall (1.5 m) and 7 ft wide (2.1 m).

‘Charles Joly’ Lilac

Charles Joly lilac

Buy Charles Joly

Image credits: Tobias Bjørkli

The French hybrid features double lilac flowers and prefers to grow in full sun. Its magenta pink flowers spread a stunning smell of sweet fragrance while blooming in the mid to late spring. Charles Joy can reach up to 12 ft tall (3.6 m) and 10 ft wide (3 m).

‘Scentara Double Blue’ Lilac

Scentara Double Blue lilac

Buy Scentara Double Blue

This early flowering hybrid lilac boasts double deep purple blossoms and thrives in full sun, emitting an intense fragrance. As a dwarf variety, it can reach a height and width of up to 8 ft (2.4 m).

Japanese Tree Lilac ‘Ivory Silk’

Ivory Silk lilac

Buy Ivory Silk

Image credits: willowbrooknurseries

From a technical standpoint, there isn’t a true “lilac tree.” This term is often used to describe a tall lilac bush that’s shaped to resemble a tree. However, if you’re seeking a lilac variety trained to grow in a tree-like form, you might consider the Japanese tree lilac (Syringa reticulata ‘Ivory Silk’).

Japanese tree lilac has creamy-white flowers, light fragrance, attractive peeling bark, and glossy foliage. It prefers full sun, blooms in early summer, and grows up to 25 ft tall (7.6 m) and 15 ft wide (4.5 m).