How to Grow and Harvest Lilacs for Cut Flowers

Common lilacs, Syringa vulgaris

Lilac (Syringa vulgaris) and other species and varieties

Lilacs are extremely popular and one of the most fragrant flowers to bloom in spring. And since they grow to big sturdy shrubs they’re a highly useful landscape plant. They make nice specimen plants (for spring) and beautiful fragrant hedge plants.

The flowers, which are one of my top four fragrant flowers, can make good cut flowers for a bouquet. They’re not very long-lasting but if you harvest, condition, and maintain them correctly you’ll get the best vase life possible, which is 3-4 days. Worth it for having that fragrance in your home! See all about that in the Harvesting section below.

Another benefit to the landscape is that they are almost completely deer resistant! At most you may get a few nibbles depending on the deer’s dietary needs at the time.

There are several species of lilac and many varieties of each are available. The original common lilac species, Syringa vulgaris, comes from Eastern Europe.  Other species, S. oblata and S. protolaciniata come from China. And others come from Korea. S. vulgaris went to France and from there many varieties were developed, called the French lilacs.

There are even modern everblooming varieties that bloom a second time on the new growth produced through  the summer. One’s called Bloomerang lilac, it’s a shorter variety to 4-6 ft. tall and wide.

The flowers attract and feed hummingbirds, butterflies, and other pollinators.

Lilac flowers and plants

Lilacs bloom sometime in mid-spring, depending on where you live and the variety you have.

The flowers form conical clusters. Each individual flower is a short tube with 4 petal-like lobes that flare outward. Some hybrids have double flowers giving each little flower 8 or even more petals for a very full appearance.

The many different varieties of lilac offer flowers in different colors and shades from traditional lilac to white, ivory, and a whole range of purples and pinks. Some even have markings like striped edges.

Each variety has a different fragrance. So if the fragrance is what you’re most after, you need to sample a variety of flowers when they’re in bloom to find what you like most.

My tip? I think the best is the common lilac, the purple Syringa vulgaris (the mother of the French lilacs). While different varieties can smell differently they also have different fragrance intensity. I feel the common lilac is both intense and a perfect fragrance, capturing high and low notes with a bit of a tangy citrus. It’s also what I grew up with, that may sway me. And I think that’s true for many people.

But the Syringa pubescens, a Chinese native is considered the most fragrant lilac, though it’s fragrance is very different from the S. Vulgaris.

The common lilac (Syringa vulgaris) grows up to 20 ft. tall, if allowed. It can be maintained at a lower height, to around 12-15 ft. tall or less. Other varieties offer various sizes to help them fit into smaller spaces or to work as smaller shrubs and hedges, such as ‘Miss Kim’ which grows to 8-9 ft. and ‘Dwarf Korean Lilac’ which grows to 4-5 ft. tall.

Lilacs spread by suckers. When you plant one it will spread wider each year, so be prepared for that. You can dig the suckers out and replant them if you like.

Lilacs are fairly long-lived, lasting 25–50 years or more if well cared for.

If you’ve ever cut your lilacs for a bouquet so you could enjoy their fragrance and beauty inside you’ve likely been disappointed to have them wilt in a few hours and never perk up. See the harvesting section below for a specific way to treat them for a few days of enjoyment.

How to grow lilacs

Zones: 3-7, with some varieties bred to perform well in zone 2 and some to flower well in zone 9; full sun; Water: regular

Lilacs need enough winter chill to bloom well, just like fruit trees need a certain amount of winter chill to bloom. So a Los Angeles area botanic garden, Descanso Gardens, bred some varieties to bloom in their warm climate. They’re called the Descanso Lilacs. And since then others have been developed. So check to be sure the lilacs you want to grow match the zone you live in.

Lilacs are quite easy to grow. They need soil with good drainage. Use an organic flower fertilizer on the surface of the soil and mulch with a good compost and wood chips to increase soil fertility and conserve moisture.

Water deeply but infrequently. The roots like to dry out between waterings. Do not keep the soil too wet. Do not plant where there will be a lawn underneath, it will be too much water.

Lilacs can be troubled with powdery mildew. It’s not too serious because it’s when the bloom is over that they’re susceptible. But it is unsightly. They need good sun and good air circulation to help keep it at bay. Six hours of direct sun is necessary.

Pruning lilacs for best bloom

The first time to prune is right after they bloom.

Lilacs bloom on second year (and older) wood. That means the new green stems that grow this year form flower buds by the end of the growing season that will bloom next spring. So after your lilac has finished blooming, prune the spent flower stem down to a pair of leaves. This removes the spent blooms and allows two branches to grow and develop flower buds during the summer, where there was one.

Height control:

One reason to prune is to keep the overall height of the plant to where you want it. Without pruning, the flowering branches get tall and the flowers are further away from your nose. To bring the lilac bush to a desired height, in winter or when pruning off the spent flowers, select some branches that are too tall and cut them back to a pair of leaves, or leaf buds if it’s winter, below where you want your flowers to be. This is called tip pruning. Avoid cutting all the stems back because it will take two years to have flowers again on the cut stems.

Remember this, if you prune all the growth back in the winter you will lose most of your next year’s blooms.

Winter pruning:

For the French lilacs, the Syringa vulgaris types, the best and most flowers are on wood that is less than five or six years old. So in winter cut the older, larger stems, or trunks, that are six years or older, down to the ground. This will stimulate more new growth that will become strong new flowering branches.

Also in winter, remove any stems that are dead or crowded. Include any tip pruning you need.

Grafted lilacs:

Some lilacs have been grafted. This is most likely the case for named varieties, but not of the common lilac. If they have, you need to be sure all new growth will be coming from above that graft. Take a look at the base of the main trunk and look to see if there is a distinct collar of thickness around the bottom, that indicates it’s grafted.

Suckers:

Where you have suckers coming up from the ground you can cut them to the soil line or a bit below. Leave some at the base of the plant to be part of your shrub. You can dig some up to plant elsewhere or leave them to increase your lilac planting. But give them some room. If suckers are coming from the roots of a grafted lilac, you don’t want those, they will be a different lilac than the one you planted, it’s the rootstock.

For the repeat bloomers: prune late in the dormant season. Cut the previous year’s growth to various lengths. And once the plant is well established, make a yearly habit of cutting out a few of the oldest stems.

For an excellent, very thorough guide, with photos, see this article from Fine Gardening.  

Harvest lilac flowers for best vase life

Everyone wants to bring lilacs into their home so they can enjoy their beauty and fragrance in the house. But they just don’t hold up once they’re cut, lasting maybe a few hours or so.

The following is detailed information that I have paraphrased from Stephanie Lindemann of the Chicago Botanic Garden. You can read her full short article and see her photos  here.

The best time to pick them in in the early morning when they are fully hydrated.

Bring your clean bucket half full of cool water with you to your lilac shrub.

Choose the flower clusters that are at least three quarters open. They don’t open much at all after they’re cut.

Cut the stem at the length you’ll need and place them in the bucket.

Place the bucket in a cool, dark place to let the flowers take up water for at least an hour.

Remove all the leaves from the stems.

Use your sharp clippers, carefully recut the stems at an angle. Then slice the blade up the stem for 1-2 inches. And finally, grab one side and twist the sliced stem backward. Immediately place the stem back into the bucket of water.

Place the bucket in a cool dark place again for 1 to 2 hours.

Now you can arrange them. Now they should last three to four days.

I don’t cut mine. Instead, I plan all sorts of gardening chores near them so I can drink in the fragrance for a good part of the day. One thing I do is sit and plant my seeds into the seed trays. The lilac fragrance makes the task so delightful. Like a little vacation.

Favorite varieties

While I think there are many nice, fragrant lilacs, my favorite remains the common purple one, Syringa vulgaris. I love the simplicity of the flowers, no extra frills, and to me it beats all the other fragrances.

Sources of lilacs

Go to your local nursery when lilacs are blooming to test what different varieties smell like. The common lilac is harder to find. But here are a few online sources:

NatureHills.com   
Arbor Day Foundation
PlantingTree.com
Fast Growing Trees
BrighterBlooms.com

The top three offer bare-root plants, which are perfect for fall or winter planting, as well as potted plants to plant anytime.

Other cutting flowers you may like:

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