- After flowering, California lilacs can be lightly pruned, but they shouldn’t ever be cut back into old wood because they rarely grow back.
- Ceanothus should be planted between late fall and early winter. As a result, it can produce sufficient deep roots during the winter rains to support it throughout the summer.
- Ceanothus is frequently accused of having a short lifespan, but this is mostly due to poor site selection. The plant will die in a few years if the soil is poorly drained and it receives regular summer irrigation. While some species and cultivars may have a limited lifespan by nature, others, including ceanothus arboreus and ceanothus thyrsiflorus var. griseus, can survive in the garden for 25 years or longer.
How should a Californian lilac be pruned?
The growth and maintenance advice provided here applies to certain members of the family of plants, but not all of them. Given the wide range of variants, we advise reading the specific needs of each ceanothus variety you choose to plant.
Where to grow
This plant, which is native to the West Coast of America, can withstand a lot of sunlight. Planting in full sun and some protection from the nastier winds and frosts they’ll encounter in Britain will promote the best growth. Anywhere with a west or south facing should work.
The majority of soils should be well-drained, neutral, or alkaline in pH, according to the general rule. Some types may survive acidity, but as we just mentioned, make sure the particular cultivars you’re trying to grow are compatible before planting them.
How to plant
Unless your soil is exceptionally well-draining, you should plant in the spring to prevent harm. In such case, you can safely plant in the fall. Digging in manure or leaf mold improves drainage and increases the likelihood that ceanothus will take.
Fertilising
Ceanothus doesn’t need to be fed, but it will profit if you do. A ring of about 3-5 cm should remain around the plant before adding a small amount of fertilizer. By doing this, you can prevent the rot that can result from fertilizing too closely to the plant.
Watering
For a few years, up until the roots are well-established, you should water your ceanothus quite frequently. This is crucial in the summer and other unexpectedly warm months.
Unless you are in a drought, your ceanothus won’t require much watering once it is established.
Pruning & deadheading
Deadheading is optional, just like fertilizing, although your plant could appreciate it. Ceanothus has a propensity to overpopulate, which can limit further growth and give them a congested appearance. Deadhead new growth or remove spent flowers to maintain a healthy appearance.
- Spring and summer flowering varieties need to be trimmed after flowering. Between 30 and 50 percent of the shoot should be pruned.
- Summer flowering varieties need to be pruned the following spring. Once more, trim 30 to 50 percent of the shoot.
Training your plant
This plant can grow on walls and other vertical surfaces with ease. To carefully secure fresh shoots to supporting elements like trellises or chicken wire, use twine. This shouldn’t harm the plant and should promote vertical growth.
Propagating Ceanothus
Cuttings can be used to grow ceanothus, with a young plant beginning to bloom roughly three years after planting. Trim a few inches of wholesome growth from this year’s season, grow for a season indoors, and then pot or plant outside.
When ought my ceanothus to be pruned?
Regular deadheading of Ceanothus is not required, and many of them produce so many blossoms that it is frequently impractical. However, pruning back spent flowers on smaller, slower-growing varieties can increase vigor, and deadheading formal wall-trained plants keeps them looking tidy.
Tying-in trained plants
Ceanothus can be trained to grow over entrances, along fences, and even up walls. New shoots will need to be tied-in to supports on a regular basis if you want to train your plant for a more formal appearance.
Garden twine is preferable for this because wire can sever growing branches. Tie firmly. At least once a year, check the ties and adjust or replace any that are damaged or have become too tight.
Depending on when the plant blooms and whether it is an evergreen or deciduous variety, ceanothus are pruned differently:
Late spring and early-summer-flowering evergreens
Immediately after flowering, prune these by trimming long, flowered shoots by a third to a half with secateurs. In the late summer, you can give these plants another gentle trim if necessary.
Ideal for plants like Ceanothus arboreus “Trewithen Blue,” Ceanothus dentatus, Ceanothus impressus, and Ceanothus thrysiflorus “Skylark.”
Late-summer-flowering evergreens
On growth from the current season, or shoots made that year, these bear flowers. On stems that sprouted the summer before, they might also produce a flush of spring blooms. The growth from the previous season, or last year, should be reduced by one-third to a half during spring pruning.
Deciduous Ceanothus
These shrubs, such as Ceanothuspallidus “Perle Rose” and Ceanothusdelileanus “Henri Desfoss,” require more frequent care in order to flower properly and are not quite as easy to prune as evergreens. They are best pruned in early to mid-spring to promote strong, new shoots each year and bear flowers on fresh growth.
Pruning young, deciduous Ceanothus
On free-standing shrubs, create a framework of branches by cutting all stems in the first year by two-thirds to an outward-facing bud. Cut down the previous season’s growth by up to two-thirds in the second year, and trim any sideshoots to a distance of 10–25 cm (4–10 in) from the main stems.
Pruning established, deciduous Ceanothus
Cut the main, flowering stems in half starting in their third growing season. Thin off crowded and unproductive growth from the plant’s center and cut back weaker sideshoots more severely, up to two buds from the main stems.
Wall-trained plants
Ceanothus can be taught to cover walls and fences, acting as a useful screen or as a focal point all by itself or as a beautiful backdrop for other plants. Being robust shrubs, care and frequent attention are required to build a framework of branches that fits the space provided but doesn’t overgrow it.
As mentioned above, the timing and method of pruning still rely on the type of Ceanothus you have selected. However, you still need to follow instructions for training as a wall shrub. For further details, see our instructions below.
When should I trim my lilacs back?
All lilacs should generally be clipped right away in the spring after they have finished blooming. Lilacs set their flower buds for the following year immediately after the current year’s flowers have faded, therefore trimming later in the summer or fall will result in the removal of most or all of the blossoms for the following year. The larger common lilacs as well as the shorter or more “shrub like” cultivars are all subject to this timing guideline. While the “when” of lilac trimming is rather simple, the “how” is a little more difficult. For the time being, we’ll refer to lilac pruning as either maintenance pruning or rejuvenation pruning to keep things simple.
Can I prune my lilacs all the way back?
Older lilacs only bloom on the tallest branches and can have stems as thick as small trees. Fortunately, rejuvenation pruning can bring back a lilac that has been dead for around three years. There are two options available to you.
Using the “third” method is a less harsh way to pull an out-of-control lilac back into shape. For three years in a row, completely remove a third of the oldest branches from the tree. The thickest stems should be removed first. Pruning overgrown lilacs is simplest in the early spring before the branches start to leaf out, even if you’ll lose some blossoms for the current season. Your overgrown lilac should consist primarily of new shoots after three years of consistent pruning. After the plant starts to bloom all over, you may start doing routine maintenance pruning.
You can take the dramatic action of pruning back the entire plant to 6 to 8 inches above the ground in the early spring if you don’t like the way your old lilac looks or you just want a quicker solution. To encourage new development, fertilize the plant with compost or a balanced fertilizer. Throughout the growing season, new shoots will appear; allow them to continue to develop over the summer. The following spring, start cutting the spindly growth while keeping the healthiest shoots and keeping an eye on the plant’s shape. By pruning the remaining shoots to just above a bud, you can promote branching. After this, continue with routine maintenance pruning.
Should Ceanothus be deadheaded?
The majority of the moisture ceanothus require should come from rainfall once they have established, with the exception of extremely hot summers.
It would not be practicable to deadhead ceanothus because they are typically covered in blossoms. To keep your plants appearing tidy, you might choose to remove any wasted blossoms.
Ceanothus does not require extensive pruning. It’s not suggested to clip an evergreen ceanothus back severely if it has outgrown its location or become slightly misshapen; it is better to replace it with a new plant. Although deciduous ceanothus can be cut back more severely, recovery time is longer.
Evergreen ceanothus should be pruned lightly after flowering, removing any dead wood and side shoots as necessary. Later-flowering types should be pruned in the spring by removing about a third of the woody growth from the previous year.
Deciduous ceanothus should be pruned in the early to mid-spring before flowering to remove any woody growth from the previous year.
Ceanothus typically don’t require food. To encourage healthy new growth, you might feed them after pruning, though. feed with a well-balanced fertilizer or mulch the base with garden compost or well-rotted manure.
Propagating ceanothus
Take semi-ripe cuttings from the current season’s growth after flowering at any time through the fall for evergreen ceanothus. Take softwood cuttings from the new growth of deciduous kinds in the spring.
Growing ceanothus: problem solving
Given the correct planting conditions, ceanothus is a shrub that should grow and be reasonably free of pests and diseases.
Yellow leaves may indicate nutrient insufficiency, especially in soils that are thin or chalky. Poor growth and scorched or brown leaves could indicate that the plant is in an exposed or overly cold location. The soil may be overly wet if there is poor growth or dieback.
Ceanothus is susceptible to honey fungus and scale insects, among other pests.
How long does a Ceanothus live?
In the Rhamnaceae family of buckthorn plants, the enormous genus Ceanothus has numerous beautiful, useful, and diverse North American species. Many are unique to Sonoma County while many are native to California. The genus has more than 60 prostrate or mounding shrubs that are typically 1-6 feet tall, while native C. arboreus and C. thrysiflorus can grow to be tiny trees that are 18-20 feet tall. California lilac, mountain lilac, wild lilac, buck brush, and, less frequently, blueblossom are examples of common names.
A distinctive leaf venation that all plants in the genus Ceanothus share makes it simple to distinguish between different species. The ovate leaves feature three noticeable parallel veins that reach from the leaf base to the outer margins of the leaf tips. The majority of the leaves have somewhat serrated edges. Normal leaves range in size from 1/2 to 3 inches and have an upper surface that is shiny. Numerous species that are resistant to deer and drought have holly-like leaves with spines.
The majority of blossoms are blue in a variety of shades, but some are white or pink. Small and produced in huge, dense clusters, the flowers are extremely fragrant—some could even say excessively so. When in bloom, ceanothus typically blooms from March to May, providing food for bees, other beneficial insects, and the larvae of some butterfly and moth species. As a result, ceanothus is often used in habitat gardens or as part of an Integrated Pest Management strategy.
Several species in the genus have the ability to coexist harmoniously with fungus and soil microorganisms to produce nitrogen-fixing root nodules. This is the rationale behind why fertilization is typically not advised. Fertilizer addition could eliminate beneficial microorganisms and make place for harmful ones. It’s best to let ceanothus plants take care of themselves.
As with so many native plants, ceanothus must have good drainage to thrive. Place rootballs on a mound that is a bit higher than the surrounding grade if the soil and drainage conditions are less than perfect. Alternatively, consider planting on a slope to help surface runoff drain more quickly.
Although some afternoon shade is helpful in hotter climates, the majority of species require full light. When established, garden plantings that tolerate summer irrigation can easily be satisfied with one or two heavy waterings per month. After the second year after planting, no extra summer water should be applied in more naturalized regions or transition zones.
While ceanothus can be shaped by tip pruning, cleaning away interior or low dead growth, and removing debris, it dislikes being severely pruned back into old wood where shoots cannot be generated. Cut a few lower limbs off and thin the tree from the inside.
Late fall through early January are the best times to plant since rainfall can encourage the development of deep roots. Watering should be sparing yet deep throughout the next summer, allowing the soil to dry between applications. Plants require very little to no water once they are established.
It’s common knowledge that ceanothus has a short lifespan, but excessive summer rainfall and soil improvements may be to blame. Native Californian flora typically cannot tolerate any of these. Although fire can occasionally limit its lifespan, ceanothus plants typically have a natural life cycle of 10-15 years in the field, with some much longer.
C. gloriosus (Point Reyes ceanothus) and C. griseus horizontalis (Carmel creeper), two species endemic to coastal regions, may take and possibly need a small amount of watering as well as shade, but they must be given fast-draining soil.
With a dense, ground-covering habit, Ceanothus gloriosus ‘Hearts Desire’ grows to a height of around a foot. Its leaves are hard and prickly, and deer rarely harm it. It is a coastal native that can withstand interior heat with a little afternoon shade. It can also stand clay.
Ceanothus gloriosus ‘Point Reyes’ is a larger, shrubby groundcover that is 1 foot by 8 feet and has tiny leathery, spherical, dark green leaves with toothed margins that resemble miniature holly leaves. It also has light blue blooms, reddish serpentine branches, and smaller leaves. In the interior, “Point Reyes” also needs midday shade and may just need a little water during the summer. Deer are fairly immune to it.
The medium blue flowers and glossy, dark green leaves of Ceanothus thrysiflorus ‘Skylark Blue’ are striking. It has a height range of 3 to 6 feet, may thrive in clay, and can withstand some deer browsing.
Ceanothus ‘Concha’ is a highly adaptable cultivar that is suitable for gardens. It has glossy dark green foliage and rich cobalt blue flower clusters in late spring, and it tolerates summer water more tolerantly than most. It can withstand summer irrigation and clay soil better than other species, growing to a height of 5-7 feet and a width of 6-10 feet.
The ceanothus variety “Joyce Coulter” has a massive mounding morphology, trailing branches, and medium-green leaves that measure 2 to 5 feet by 8 feet. It blooms in the spring with 3-inch, medium blue flower spikes that are extremely fragrant. This plant blooms profusely, is tolerant of drought, and has some deer resistance. Compared to many other cultivars, it can handle clay, summer watering, and shearing better.
The stronger the leaf’s resistance to deer, the smaller, more spiky, and tougher it is. On a rounded shrub that grows to be approximately 6 feet tall with arching branches, Ceanothus ‘Blue Jeans’ bears purple-blue flowers and little, spiky leaves that resemble those on holly. Similar to this kind is “Julia Phelps,” which has tiny, crinkly, dark green leaves with serrated edges and dazzling dark indigo blooms. In the spring when the blossoms first show, the entire plant appears purple. It grows to a height of 8 feet inland but stays approximately 6 feet tall along the coast. With its small, crinkled, nearly black-green leaves and deep blue blossoms, “Dark Star” is about 6 feet tall and spreads 8 to 10 feet wide. It is deer resistant. Summer irrigation on a sparse basis is acceptable.
Ray Hartman, which may grow to a height of 15 feet and a width of at least 10-15 feet, acts like a tiny tree. In a landscape context, its magnificent big clusters of medium blue flowers are particularly impressive.