Bloomerang® Dark Purple. Photo by: Spring Meadow Nursery / Proven Winners.

These easy to grow, low maintenance and hardy shrubs grow best in northern states and areas with cool summers. The heavily-scented purple flowers on the common lilac (Syringa vulgaris) bloom in late May. This upright, multi-stemmed, deciduous shrub can last decades in your garden. There are bush varieties available that range from 4 to 20 feet tall, and tree varieties that can reach heights of up to 30 feet. The large panicles of fragrant flowers attract hummingbirds, butterflies and other pollinators. The cut flowers are perfect to bring the scent of spring right into your home.

LILAC BASICS

Zones:

Most lilacs are hardy in zones 3-8; however, there are varieties cold hardy to zone 2, like Scentara® Double Blue (S. hyacinthiflora), and heat tolerant to zone 9, like 'Big Blue' (S. vulgaris). They all require a cold, dormant period over winter.

Height/Spread:

The common lilac (Syringa vulgaris) grows 12 to 15 feet tall and 10 to 12 feet wide. There are many smaller dwarf varieties that mature at 4 to 6 feet tall and 3 to 7 feet wide. Japanese tree lilacs (Syringa reticulata) can reach 25 to 30 feet tall.

Exposure:

Lilacs need a minimum of 6 hours full sun for best flowering.

Bloom Time:

Most bloom in late May; however there are early spring, mid spring, and late-season blooming varieties, as well as new re-blooming varieties, like the Bloomerang® series.

Color:

The common lilac (Syringa vulgaris) has purple blossoms, dark gray-green to blue-green foliage (with no fall color change), and gray to gray-brown bark. However, there are officially 7 colors of lilac flowers: white, violet, blue, lavender, pink, magenta and purple with many shades within each color.

Other:

California lilac, mountain lilac and wild lilac aren’t true lilacs, but actually belong to the genus Ceanothus. Summer lilac is often used to refer to butterfly bushes, especially those types that are sterile and non-invasive.

PLANTING LILACS

Planting Bloomerang® Reblooming Lilacs

When to plant:

Lilacs can be planted in early spring after the ground thaws or in fall before it freezes.

Where to plant:

For healthy and productive lilacs, plant them in an area with well-drained soil and where they'll receive at least 6 hours of sunlight daily. They'll also benefit from good air circulation to help prevent powdery mildew. Avoid planting in an area with grass directly underneath, as the regular watering can be too much for them. Also, grass fertilizers tend to be high in nitrogen, which is bad for lilacs. Clear a 2- to 3-foot area around the base and apply a loose layer of mulch to the area. Jerry Fritz, of Linden Hill Gardens in Pennsylvania, recommends not letting the mulch touch the bark to help prevent insect borers.

How to plant:

When planting container-grown lilacs, dig a hole twice as wide and just as deep as the container. Gently remove the plant from the container and place it in the hole. Spread out the roots and back-fill with soil mixed with compost and water well. A layer of loose mulch can be added, again, keeping the mulch from touching the bark. Spacing should be 5 to 15 feet apart depending on the variety.

LILAC CARE

Photo by: J Gade / Shutterstock.

Pruning lilacs:

Since they bloom on old wood, lilacs should be pruned soon after flowering. Next spring’s flower buds are set almost immediately after flowering, so if you wait too long to prune, you’ll be sacrificing next year’s flowers. Prune not only for the health of the shrub by removing dead, diseased, or damaged branches, but also for shape and size. Pruning will also help in preventing powdery mildew on the leaves by improving air circulation throughout the plant. They are quite hardy and will withstand hard pruning, even down to as low as 6 to 8 inches; this may be needed to revive or rejuvenate an older specimen. However, keep in mind, it may take a few years to completely grow back, and blooms will be diminished in the first 2 to 3 years. Spent blooms should be deadheaded. Root suckers on grafted lilac plants should be removed when pruning.

Amendments & Fertilizer:

Lilacs won’t bloom well if over-fertilized. A small amount of 10-10-10 applied in late winter is sufficient. They do like rich soil, so add compost if needed. Fritz also says that ash from the fireplace can be sprinkled on soil around the base of the shrub.

Watering:

Water regularly to establish a deep root system. It is best to water them at soil level and avoid overhead watering. Once established, lilacs are water wise. Water weekly in dry conditions, more often in extreme heat. Too little water can result in wilting or distorted leaves.

Propagation:

Seeds can be sown in spring. Seeds taken from specific cultivars may not come true from seed. In early summer, shoots from the base of the trunk can be used to propagate (not recommended for grafted varieties). Dig down at the base of the trunk and cut away the shoot, being sure to include some roots.

Diseases and Pests:

Powdery mildew on the leaves can be a frequent problem in summer and can greatly affect the foliage; however, it generally doesn’t do any permanent harm. Cultivars such as ‘Miss Kim’ have more resistance to mildew. Blights, leaf spots, and wilt can also affect them. Pests such as scales, borers, leaf miners, and thrips can be a nuisance as well.

LILAC PICTURES

Swipe to view slides

Photo by: Spring Meadow Nursery / Proven Winners.

Bloomerang® Dark PurpleBuy now from Proven Winners
Reblooming lilac

Zones: 3-7
Exposure: Full sun
Height/Spread: 4 to 5 feet tall and wide
Bloom time: Spring and again in late summer through fall
Flower color: Dark purple

Blooms in spring and again mid-summer through fall. Good powdery mildew resistance. Compact variety suitable for containers. Others within the series: dwarf purple, dwarf pink, purple, and 'Pink Perfume'.

Photo by: Spring Meadow Nursery / Proven Winners.

Scentara® Double BlueBuy now from Proven Winners
Early-blooming lilac

Zones: 2-8
Exposure: Full sun
Height/Spread: 6 to 8 feet tall and wide
Bloom time: Spring
Flower color: Purple-blue

Highly fragrant and a heavy bloomer, this lilac also has excellent disease resistance.

Photo by: Radim Beznoska / Alamy Stock Photo.

Syringa vulgaris
Common lilac

Zones: 3-8
Exposure: Full sun
Height/Spread: Up to 12 feet tall and 10 feet wide
Bloom time: Mid-Spring
Flower color: Purple

Photo by: Maria Evseyeva / Shutterstock.

Syringa vulgaris ‘Sensation’
Common lilac

Zones: 3-7
Exposure: Full sun
Height/Spread: 8 to 15 feet tall, 6 to 12 feet wide
Bloom time: April to May
Flower color: Purple, white edged single flowers

Photo by: Maxal Tamor / Shutterstock.

Syringa vulgaris ‘Madame Lemoine’
French lilac

Zones: 3-8
Exposure: Partial to full sun
Height/Spread: Up to 15 feet tall, 12 feet wide
Bloom time: Spring to Summer
Flower color: White

Photo by: Garden World Images, Ltd / Alamy Stock Photo.

Syringa vulgaris ‘Wedgewood Blue’
Common lilac

Zones: 3-7
Exposure: Partial to full sun
Height/Spread: 4 to 6 feet tall and wide
Bloom time: Spring to Summer
Flower color: Pink buds, blue flowers

Photo by: Maknad / Shutterstock.

Syringa vulgaris ‘Krasavitsa Moskvy’ (Beauty of Moscow)
Common lilac

Zones: 3-8
Exposure: Partial to full sun
Height/Spread: Up to 10 feet tall, 8 feet wide
Bloom time: Spring to Summer
Flower color: Pink buds, pink-to-white flowers

Photo by: Garden World Images Ltd / Alamy Stock Photo.

Syringa pubescens subsp. patula ‘Miss Kim’
Manchurian lilac

Zones: 4-8
Exposure: Partial to full sun
Height/Spread: 6 to 8 feet tall and wide
Bloom time: Spring
Flower color: Deep purple buds, lavender flowers

Blooms in spring and re-blooms mid-summer through fall. Good powdery mildew resistance. Compact variety suitable for containers.

Photo by: Ilona5555 / Shutterstock.

Syringa meyeri ‘Palibin’
Korean lilac

Zones: 3-7
Exposure: Partial to full sun
Height/Spread: 4 to 6 feet tall, 5 to 7 feet wide
Bloom time: Mid-May
Flower color: Pale lilac

Compact dwarf variety.

Photo by: R Ann Kautzky / Alamy Stock Photo.

Syringa reticulata ‘Ivory Silk’
Japanese tree lilac

Zones: 3-7
Exposure: Full sun
Height/Spread: 20 to 15 feet tall, 15 to 20 feet wide
Bloom time: Spring to early summer
Flower color: Creamy white

Effective as a single specimen, along streets and in lawns.

LILAC DESIGN TIPS

  • Lilacs are an excellent choice for cottage-style gardens.
  • Fritz recommends planting where their fragrance can be enjoyed: near a pathway, main door or window.
  • Use as single specimens, in small groups, mixed in borders, or as a deciduous hedge.
  • The blooms make excellent cut flowers and will last 3 to 5 days in fresh water. Cut single flowers when about one-third of the buds are open, cut double flowers when about half of the buds are open, cutting them at a slight angle.
  • Some suggested companion plants: boxwood, weigela, coneflower, juniper, maiden grass, Shasta daisy, phlox, and black-eyed Susan.

FREQUENTLY ASKED QUESTIONS

Why isn't my lilac blooming?

If your lilac is getting too much water or fertilizer, or not enough sunlight, it may experience diminished flower production. Also, if it was recently hard pruned, it may take a few seasons to get back to its full glory. Also, make sure that your annual pruning is being done correctly and you aren’t cutting off the “old wood” branches that produce the flowers.

Are lilacs poisonous?

They are not toxic to humans or animals.

Are lilac roots invasive?

Their roots do need space as they will spread to about 1-1/2 times the width of the shrub, but are not considered to be invasive.

LILAC FESTIVALS

RELATED:
Flowering Shrubs
Hydrangea

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