Lilac trees grow best in the fall, just after the leaves have fallen and before the ground freezes. Lilacs can be planted in the spring before the buds open. However, springtime is a relatively brief season, therefore transplanting at this time is only advised in regions with really harsh winters.
What distinguishes a lilac bush from a lilac tree?
Lilac bushes (also known as shrubs) are characterized by their numerous woody stems that emerge from the plant’s base. In contrast, the trunk of the majority of lilac trees is the only woody stem. However, your neighborhood garden center might also sell shrub lilacs that have been grafted onto a single stem to give them the appearance of miniature trees.
The choice between a lilac tree and a lilac bush is typically determined by the amount of space available. Lilac bushes come in a range of sizes and can be placed in more compact areas of a garden. A lilac tree requires space to reach heights of 20 feet and widths of 15 feet. Both require sunlight to bloom well.
Where should a lilac tree be planted for maximum benefit?
When the lilacs begin to blossom, it is a solid indicator that spring has arrived for good. While many people only have a limited knowledge of common lilac (also known as French lilac) shrubs that can reach a height of 15 feet or more, there are now a lot more options available than there were fifty years ago. Some varieties that rebloom enhance the garden’s appeal the entire growing season.
How to Choose Lilacs
The common lilac is what you will most likely find when you go plant shopping. This traditional plant comes in a variety of cultivars and variations, each of which yields fragrant spring flowers in pink, purple, white, or even combinations of those hues. Common lilacs are typically the most fragrant variety of lilac and can grow to be rangy and large.
Rebloomers have arrived in the garden center thanks to recent introductions of hybrids between the common lilac and other shrub-type lilacs. Some of these more recent types are a little less fragrant, but they also tend to be smaller, bloom more frequently throughout the growing season, and have fewer powdery mildew issues.
The tree lilac is another common variety of lilac. It can grow to a height of around 20 feet and blooms with cream-colored flowers in the middle of the summer. Though it doesn’t require much trimming, keep in mind that the tree lilac is a tree, not a shrub.
Where to Plant Lilacs
Lilacs should be planted in full light (at least 6 to 8 hours per day), as too much shadow will prevent them from blooming. Lilacs also prefer moist, well-drained soil that is slightly alkaline.
When to Plant Lilacs
Before the ground freezes in the late fall is the ideal time to plant lilacs. After the earth thaws in the early spring, that is the next ideal period to plant. Lilacs will likely need to be planted as soon as you can locate them at the garden center, which is great; if you choose to do so during a warmer season, they might require additional watering.
How to Prepare the Soil for Planting Lilacs
A soil test should be performed prior to planting since lilacs thrive in slightly alkaline (6.5 to 7.0 pH), moist, well-drained soil that is high in organic matter. Lime must be added to raise the pH if it is below 5.5. It’s time to get the soil ready when you’ve obtained the ideal pH. Improve individual planting holes by mixing Miracle-Gro Garden Soil for Trees & Shrubs in a 50:50 ratio with the natural soil to give lilacs a nutrient-rich start. Iron and phosphorus are also present in this garden soil to promote root development and ward off leaf fading.
Lilac trees should be planted when?
I had a variety of roles as a founding worker at Gardener’s Supply over the years. I currently run my own business, which is called Johnnie Brook Creative. A huge vegetable garden, a seasonal greenhouse, a cutting garden, perennial gardens, a rock garden, a shade garden, berry plantings, numerous container plants, and a meadow garden are among the gardens surrounding my Richmond, Vermont, home. The garden is the only place I would rather be. Check out this Garden Gate magazine video interview from January 2021 if you’re interested in learning more.
Among all shrubs, lilacs are among the easiest to maintain. Their requirements are straightforward: lots of sunlight, excellent drainage, nutritious soil, and yearly pruning. The only maintenance you’ll need to perform is yearly trimming to preserve a great shape, so pick your planting location wisely. You’ll be rewarded with bouquets of scented blooms in the spring.
Lilacs can be planted either in the fall before the ground freezes or in the spring after the earth has thawed. Lilacs are frequently supplied bare-root and dormant in the spring. The plants are merely “sleeping,” not dead. When the roots arrive, take off any packing and soak them in lukewarm water for 10 to 15 minutes. Read How to Plant a Bare-Root Tree or Shrub for planting guidelines. Lilacs are also available in containers. Read How to Plant a Tree or Shrub for details on planting procedures.
Which lilac has the strongest scent?
I had the impression that lilacs were meant for me at times. Working with my grandfather, a nurseryman who specialized in these enthralling beauties, for many hours during my formative years. The tall, pink-flowered “Esther Staley” lilac that grew next to my grandparents’ back door captured my attention the most. Like some people dream of authoring the great American novel, I once fertilized that plant in the hopes of creating a fantastic new lilac. Even though my first attempt at hybridizing failed, I still enjoy breeding lilacs. I also keep an eye on the lilac collection at the Boston-area Arnold Arboretum of Harvard University.
Why are lilacs so alluring? Certainly, the approach of spring is signaled by their wonderful scent. Lilacs are exceptionally simple to grow, and they are distinctive enough to define a color and a fragrance. Additionally, lilacs now come in an astounding range of colors, habits, bloom sizes, shapes, and flowering times. Previously, they were only available in two flavors—purple and white.
There are many modern uses for these traditional plants. Species that are vibrant and fragrant may draw attention. Lilac shrubs can be arranged to create a hedge or screen. Lilacs that grow tall provide shade for a patio. Lilacs can also be underplanted with perennials that will bloom at the same time as them, such as bleeding heart (Dicentra spectabilis) or spring bulbs.
With lilacs, fragrance is the number one priority
Different lilacs have different levels of fragrance. For instance, many white lilacs only have a little aroma. Other lilacs range in flavor from quite sweet to extremely pungent. I am able to perceive pleasant smells, yet my olfactory system seems to swiftly adapt to a fragrance. This makes it challenging to discern between the aromas of various flowers. I still grin when I smell lilacs.
I started a project a few years back to keep track of which lilacs were and weren’t fragrant. I had to find willing sniffers. Now, based on other people’s noses, I can offer fragrant lilacs with assurance.
French hybrids are the best-known lilacs
All lilacs are members of the Syringa genus, which has roughly 20 species and hundreds of widely grown cultivars. Asian species predominate. None of them were born in North America. The common lilac, S. vulgaris, with its heart-shaped leaves and big blooms that bloom around the third week of May here in Boston, is significantly different from many of the species, or wild, lilacs.
The common lilac is an Eastern European native that was brought to Western Europe before 1600 and most likely from there to North America. Named cultivars weren’t created until the 1800s. Since so many of these superior cultivars originated in France around 1900, the word “Even though many common lilac cultivars were developed in other European nations or North America, the term “French Hybrid” is frequently used to refer to all of these varieties.
Other Syringa species have some highly intriguing characteristics outside of the common lilac. Each has a pleasant scent, however some are fairly distinct from S. vulgaris.
S. pubescens, a native of China, is the lilac that is typically regarded as having the strongest scent. It has tiny, purple-tinged white blooms. The aroma is sweet and spicy, extremely unlike the conventional scent “lilac aroma
An lovely native of China and Korea, S. oblata is an early bloomer and blooms approximately two weeks before the common lilac, which it mimics in appearance and aroma. This species is well recognized for being the parent of the S. hyacinthiflora early-flowering hybrid group. The common lilac serves as the other parent. S. oblata and common lilac cultivars have been crossed by breeders to produce some lovely early-flowering, fragrant selections, many of which are disease-resistant. This collection contains some of my favorite cultivars. These include my favorite white lilac, “Sister Justina,” as well as the exquisite lilac-pink varieties “Asessippi” and “Excel.” These three generate a lot of flowers from the top of the plant to the ground, although none of them have particularly large blooms. They have a pleasant scent, and in Boston, the common foliar diseases powdery mildew and leaf-roll necrosis rarely affect them.
Because of its small, intricately cut leaves that resemble ferns, another Chinese species known as S. protolaciniata (which is related to S. laciniata) is called cut-leaf lilac. Unlike the typical lilac, it has inflorescences that appear all the way down the stem from a branch terminal back approximately 18 inches, producing a large number of tiny, light-purple flowers. Some plants can grow up to 8 feet tall and 10 feet across, although they are always incredibly delicate-looking.
Some lilacs are trees
There are tree lilacs that can grow to the size and shape of an apple tree rather of just being large shrubs. They grow beautifully as shade trees, and the second season of interest is provided by their striking bark. My garden is now bordered by a sizable, untrimmed hedge of tree lilacs that was originally planted as a nursery row.
A week to ten days following the late lilacs, which bloom around a month after the early lilacs, come the tree lilacs. They have ivory blooms with a privet-like scent, which is a related relative. Compared to the Chinese tree lilac, the Japanese tree lilac (S. reticulata) often has broader, rounder leaves (S. pekinensis). Both tree lilacs have lovely bark that resembles cherry bark, but the Chinese tree lilac sheds more frequently and comes off in strips. This characteristic makes the cultivar “China Snow” beautiful. The Japanese tree lilac has a cultivar called “Ivory Silk” that is now widely accessible. In addition to being useful in gardens, it seems promising as a little street tree.
A few are short and sweet
I’ve planted a kind of S. patula called “Miss Kim” on either side of my front door. ‘Miss Kim’ is a little shrub that reaches heights of 8 to 9 feet while not being a dwarf. Its leaves acquire a port-wine hue, making it one of the few lilacs with good fall color. It blooms a week or so after the common lilac and has a profusion of deliciously fragrant blooms.
The cultivar commonly referred to as “Dwarf Korean Lilac” is another small lilac. This lilac, S. meyeri ‘Palibin,’ though a dwarf, is a cultivar of a Chinese species rather than a Korean one. Its rarely taller than 4 to 5 foot plants have tiny, circular leaves and tiny blooms. The blooms are a light purple color in the buds, but when they are fully opened, they are white, numerous, and fragrantly pleasant. This variety can be utilized to grow a short hedge.
Late-blooming lilacs have a distinctive look and smell
About a week to ten days after the common lilacs, the late lilacs blossom. As opposed to breeding within a species, most of them are the result of hybridizers crossing two or more species and choosing their strongest offspring. To produce the hybrid group S.prestoniae, Canadian plant breeder Isabella Preston initially crossed S. komarowii ssp. reflexa and S. villosa. Others have since crossed late-flowering species with Preston lilacs. However, these late-flowering lilacs don’t have the typical “lilac” appearance or scent. Sincerely, I believe that these bushes would be more well-known if they were known by a different name. Miss Canada, a true red-pink lilac, and ‘Agnes Smith,’ with white blossoms, are a couple of my favorites.
Lilac flowers range from creamy shades to purples
Although I like purple, I grow lilacs in a variety of hues, including white, blue, purple, magenta, violet, and pink. Even the yellow-lilac S. vulgaris ‘Primrose’ exists. It is a rich, creamy yellow, not the color of dandelions. S.vulgaris ‘Sensation’ is another unusual cultivar; it has purple flowers with white pinstripes encircling each petal. I grew a tall, slender variety of lilac named “Krasavitsa Moskvy,” a Russian introduction of the common lilac, next to my back door. I’m reminded of pink opals when I see its emerging buds, which later bloom into double, white blooms.
Although lilac flowers typically have four petals, many double-flowered cultivars have also been created by hybridizers. Each of these flowers has more than four petals, frequently 12 or more. These can occasionally be put hose-in-hose, which means a four-petal bloom is enclosed by another four-petal flower. Some of the more recent introductions have all of the extra petals radially arranged daisy-style in the same plane.
What qualities should a lilac have? Naturally lovely blossoms. In addition, flowers should be plentiful, fragrant, and come in the color of your choice. And being resistant to sickness is a significant bonus.
My preferred lilacs in the past had huge blossoms. Since then, I’ve come to understand that even the largest lilac flowers can only be seen up close, and that the majority of lilacs are best seen from across a garden or even a street. The quantity of bloom therefore becomes crucial, as well as presentation. You might need to smell your lilacs from a window on the second floor if all of your plant’s blossoms are at the top. Many lilac cultivars grow so tall that single-story homes cannot accommodate them.
Lilacs are easy to grow
As simple to raise as vegetables are lilacs. Their requirements are also not that dissimilar. Lilacs grow best in broad sunlight and on healthy garden soil that is neutral to slightly alkaline in pH. In these areas, they will withstand less than perfect conditions, although providing for the needs of the plant will yield better floral results.
Lilacs are typically thought of as cold-climate plants. The majority of lilacs are hardy in USDA Hardiness Zones 3 to 7, therefore when climate is an issue, heat tolerance comes into play. Gardeners in warm climates have reason for optimism. Recent selections developed at Los Angeles’ Descanso Gardens can withstand the heat and the absence of a chilling time. And the University of California, Riverside campus is home to lilac trees. I’ve heard that my old favorite, the early-flowering S.hyacinthiflora ‘Excel,’ is one of the best varieties there.
Bear in mind that lilac flower buds form in the summer before blooming when you are trimming or pruning them. Almost usually, winter pruning leads in fewer blooms the following spring. Lilacs should be pruned as soon as their blooms start to fade for the greatest flowering.
Lilac leaves frequently get powdery mildew on them, especially in humid environments. Since it appears in the late summer and early autumn, after the majority of the growth season, it is typically more of a nuisance than a hazard. Fungicides can be used to control it, however I advise cultivating the plants that are least impacted. The plants that are suggested in this article have only mild to moderate leaf disease symptoms. Site and environment, however, also influence the likelihood of infection.
Another foliar disease called leaf-roll necrosis is thought to be brought on by air pollution and can manifest hundreds of kilometres away from large cities. Similar to mildew, symptoms typically show up in the late summer and early fall. Each leaf coils upward as the leaf margins frequently die and turn dark. The symptoms may be so unpleasant that it may appear as though the plant will perish. Fortunately, at that time, lilacs have finished growing for the most part, and new spring leaves are typically healthy. Again, cultivars respond to injury in varied degrees, so look for ones that maintain their attractiveness throughout the season.