Syringa

syringa

( sih - RIN - guh )

At-A-Glance Information

Commonly known as Lilac, this genus of deciduous shrubs (and a few small trees) needs light shade in the warmest climates of its zone range and regular water. These shrubs are native to woodland and scrub areas in southeastern Europe over to eastern Asia. The beautiful clusters of bright flowers will attract birds and butterflies to your garden. Flowers are fragrant and come in a variety of colors, usually shades of pink, purple and white. They are commonly medium to large sized shrubs, and are classic staples for cold-weather gardens.

syringa Species and Varietals

The genus Syringa includes 12 species of flowering woody plants in the Oleaceae family, and is closely related to Ligustrum. Syringa was first described by Carl Linnaeus in 1753 when he published a description of the plant in Species Plantarum. The genus name is derived from the ancient Greek word 'syrinx', meaning pipe or tube, referring to the hollow branches of the species Syringa vulgaris. The common name Lilac refers to the bluish color of the flowers on many shrubs in this genus, and the moniker 'French Lilac' refers to a number of modern cultivars. The ideal growing zones for Lilac vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Syringa emodi (Himalayan Lilac)
These plants reach up to 16 feet tall and 13 feet wide, producing vigorous, upright branches with silver-grey bark. The species is native to Afghanistan, Pakistan, Kashmir, and Nepal. Leaves are elliptical and silver-grey, and flowers are purple, pale lilac, or white, and have an unpleasant aroma. Blooms are present from May through June, followed by fruits in September and October. Notable cultivars include 'Aurea', 'Elegantissima', and 'Variegata'.

Syringa 'Betsy Ross'
This variety grows well in zones 2-12, 14-16 and 18-22, and has great disease resistance and profuse white blooms. Betsy Ross performs well in mild-winter climates and reaches 10 feet tall and 13 feet wide.

Syringa x chinensis (Chinese Lilac)
This species grows well in zones A2, A3, 1-11, 14-16 and 18-21. It is a hybrid between Syringa vulgaris and Syringa x persica. It reaches 15 feet tall and just as wide, with many clusters of fragrant rose-purple blooms. Great for mild-winter, hot-summer climates. Choice selections include 'Alba' (with white flowers) and 'Lilac Sunday' (with single, light purple blossoms).

Syringa x hyacinthiflora
This species does well in zones A2, A3, 1-12, 14-16 and 18-22 and is relatively heat-tolerant. There are many varieties in this group of hybrids, with single or double flowers in shades or purple, pink, magenta, and white. Newer selections include 'Declaration' (with red-purple flowers), 'Old Glory' (with great disease resistance), and 'Maiden's Blush' (with pink flowers).

Syringa 'Josée'
This dwarf variety grows well in zones A1-A3, 1-11 and 14-16 and reaches 6 feet tall and 5 feet wide, with lavender-pink fragrant flowers that bloom most profusely in spring and intermittently throughout the rest of the year. Variety 'Bloomerang Purple' has lavender flowers.

Syringa josikaea (Lady Josika's Lilac)
These plants are native to central and eastern Europe, and form large shrubs with green foliage. The species is currently considered endangered due to habitat destruction in its native range, but is commonly used as a garden ornamental. Individual plants reach between 6.5 and 13 feet tall when mature, and produce dark pink flowers with a strong fragrance in summertime.

Syringa komarowii (Nodding Lilac)
These shrubs reach between 10 and 20 feet tall at maturity, and produce erect branches and green foliage. Flowers range in color from pink to mauve, and sometimes have white bases. They bloom in early summertime, later than most other species in the genus. Panicles of flowers often hang from branches, hence the common name Nodding Lilac.

Syringa x laciniata (Syringa x persica laciniata) (Cut-Leaf Lilac, Cutleaf Lilac)
Best in zones 3-12, 14-16 and 18-22, this species has an open habit and reaches 5-8 feet tall and about as wide. Leaves are divided, and flowers are fragrant and lilac-colored.

Syringa meyeri 'Paliban'
This species does well in zones A2, A3, 1-9 and 14-16 and has a dense growth to 5 feet tall and just as wide, though it can be kept smaller (around 3 feet) if desired. This species is sometimes grafted onto trees to make it a bit taller. Flowers have a slight fragrance and are purple when new, fading to pink with age.

Syringa oblata (Early Blooming Lilac, Broadleaf Lilac)
These shrubs reach between 12 and 16 feet tall when mature, and produce light pink, lilac, or white flowers in April and May, which is earlier than most other species in the genus.

Syringa x persica (Persian Lilac)
This hybrid does well in zones A2, A3, 2-12, 14-16 and 18-22 with a graceful, loose habit. It reaches 6 feet tall and just as wide. Flowers are fragrant and pale violet, and appear along the gracefully arching branches.

Syringa x prestoniae
Best in zones A1-A3, 1-11 and 14-16, this hybrid species is extra hardy and is native to Canada. It reaches 12 feet tall and wide, with flowers blooming all along new growth towards the end of the flowering season for most Lilac species. Flowers are not as fragrant, but this group offers a wide range of flower colors.

Syringa pubescens patula 'Miss Kim'
This species grows well in zones A2, A3, 1-9 and 14-16. and has a dense, rounded habit to 8-9 feet tall and just as wide. Sometimes grafted onto a tree species. Flower buds are purple, and open to reveal very fragrant, ice-blue-pink flowers.

Syringa reticulata (Japanese Tree Lilac)
Zones A2, A3, 1-12 and 14-16; native to Japan. This species reaches 30 feet tall and 20 feet wide, with glossy reddish-brown bark and white, musky-scented flowers that bloom on new wood. This species is great as a small shade or street tree, and does well in cooler climates. Variety 'Ivory Silk' reaches just 20 feet tall and has creamy flowers.

Syringa vulgaris (Lilac, Common Lilac)
This species grows well in zones A1-A3, 1-16 and 18-22, and is native to eastern Europe. Can reach 20 feet tall and wide, spreading via suckers. After 2-5 years, this species will bloom at its peak, with pinkish or bluish lavender flowers in the middle of spring. Fantastic fragrance, and great as cut flowers in fresh arrangements.

Caring for and pruning syringa shrubs

Lilacs do very well in areas that receive cold winter temperatures and need well-draining neutral to slightly alkaline soil. Amend with lime before planting if you have acidic soil. Lilac shrubs love being planted in full sum (at least 6 hours of direct sun per day); they will perform and flower best in this exposure. Ensure that you are planting your Lilac in an area where they will get adequate air flow; they can have issues with mildew if they are too crowded. They need regular waterings, especially during dry spells, but are relatively drought tolerant as well once established. The best way to water Syringa shrubs is deeply and consistently. Apply a layer of mulch after planting to increase soil moisture retention and suppress weed growth around the base of the plant. Lilacs do not need heavy fertilization, unless soil is especially poor. In this case, a slow-release balanced fertilizer is best when applied in early springtime before new growth pops.

Pruning lilac shrubs is simple; a main tip is to not prune to heavily, as some lilacs bloom on old wood and pruning too late in the season as well can reduce the number of flowers in the following year. Pinch back young plants until they have established themselves. Many Lilac plants will bloom on new wood, so prune these plants just after blooms have faded. Remove the spent bloom clusters to the first pair of leaves. Cut out a few of the oldest stems to the ground annually to encourage more foliage growth.

Propagation

Syringa can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Syringa by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
Choose the plant you'd like to propagate. If you'll be doing a softwood cutting, take it in early summertime, and if you are harvesting a hardwood cutting, take it in late fall or early springtime. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Syringa by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed pods are dry, hard brown capsules, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Caesalpinia seeds have a hard coating that protects them, but this coating also makes it a little difficult to get them to germinate. We can help the process along by soaking them in room temperature water for 24 hours. Do this with as many seeds as you can; they will probably not all sow, and the ones that do will be of varying characteristics. The more seeds you plant, the more chances you will have to get the resulting shrub you want. After soaking, place them in a moistened bed of peat moss inside of a plastic resealable bag and put the bag in the refrigerator for 90 days. After this period has passed, you can take them out and sow them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Syringa fruit is a dry, brown capsule that splits in half when mature and releases winged seeds.

Syringa seeds.

Problems and Pests

Syringia shrubs commonly suffer from the following pests and diseases:

Aphids
Powdery Mildew
Leaf Miner
Scale
Stem Borer
Bacterial Blight
Leaf Spot
Downy Mildew

For more information on these issues, including how to solve them, see the following links:

Pests & Pest Management

Plant Issues

Gallery

Situate these shrubs near gathering areas or pathways, where their fragrance and beauty cam take center stage.

Syringa shrubs form beautiful walls of color in this lawn corridor.

Butterflies love Lilac shrubs.

The sapwood in some species has streaks of purple or brown.

In Greece, Macedonia, Lebanon and Cyprus, Lilac shrubs are associated strongly with the religious holiday Easter, and are called paschalia.

Lilac shrubs flower in a variety of colors, commonly with a tint of blue.

Syringa vulgaris is the state flower of New Hampshire; it is used as a symbol of "that hardy character of the men and women of the Granite State".

There are Lilac festivals held across the United States and in other countries every year, in places like Ontario, Illinois, Boston, New York, Washington, and Calgary.