Lilacs are renowned for their longevity and hardiness. Numerous lilac shrubs reach ages of greater than 100. They frequently outlive the residence of the gardener who planted them due to their extended lifespan. As a result, if you’re driving along a country road and come across a few what appear to be random lilac bushes, it was probably a farm or house a century ago.
Try growing lilacs in your garden if you haven’t already. They not only return every year, but they also put on a display for the senses with vibrant blossoms and enticing scents. Lilacs have a lot to offer, and learning about their history demonstrates just how unique these plants are.
How can an ancient lilac tree be revitalized?
The common purple lilac is a hardy, dependable shrub that can grow up to 20 feet tall. Unfortunately, the lower, shady sections of lilac shrubs typically lose their leaves as they get older. Large, overgrown specimens as a result are frequently leggy and ugly. Pruning can restore or rejuvenate old, neglected lilacs. Home gardeners have two alternative pruning techniques to pick from.
Cutting the entire plant back to within 6 to 8 inches of the ground in late winter is one method of renewing a huge, overgrown lilac (March or early April). A significant number of shoots will sprout during the growth season as a result of this aggressive pruning. Select a few sturdy, robust shoots to construct the shrub’s framework, keeping a few of them, and cut off all the others at ground level in the late winter of the next year. To promote branching, head (clip) back the retained shoots to just above a bud.
Cutting back the overgrown shrubs over a three-year period is a second method for pruning mature lilacs. In late January, start the process by digging up and removing one-third of the big, old stems. The following year, trim out half of the remaining old stems (again in late winter). Additionally, trim out some of the recent growth. Keep a few healthy stems that are evenly spaced apart and cut off the rest. In the third year’s late winter, completely remove all of the old wood. It is also necessary to thin the fresh shoots more. This pruning technique should enable you to take pleasure in blossoms every spring because lilac wood must be three years or older before it blooms.
Within a few years, with the right pruning, an old, overgrown lilac can be converted into a robust, appealing shrub. Pruning should be a frequent component of the lilacs’ management regimen after they have been revived. By cutting a few of the oldest branches every three to five years, the shrub can be kept strong and healthy.
(This article, which first published in the Sunday edition of the Lincoln Journal Star Newspaper in February 2005, has since been amended. Consult the Terms of Use for details on how to copy this content and use any images or visuals.)
Fungal diseases
This season, the Lilac Pseudocercospora leaf spot, a fungus, was detected in lilac samples examined by the Plant Disease Clinic. The same symptoms have been recorded (yellowing then browning leaves, dieback).
The PDC places a strong emphasis on sanitation because it appears that Pseudocercospora spores can survive on plant detritus for a number of years (leaves, stems, dead flowers, bark).
- To assist lessen the possibility of reinfection the next season, remove fallen leaves.
- Consistent watering and renewal cutting to reduce density will sustain the stressed plant.
Several of the plants in our landscapes, including lilacs, are afflicted by verticillium wilt. Verticillium dahliae and Verticillium albo-atrum are the two fungi that cause it. For a plant with this fungus infection, there is no cure.
- As a result of the fungi clogging the branch’s vascular system and preventing the transfer of water and nutrients, individual branches turn brown and die quickly.
- To increase plant longevity, increase watering and fertilization.
- The disease can spread across all sections of the afflicted plant, thus the best preventive is to buy resistant cultivars and practice proper hygiene.
Insects
The Lilac Borer, sometimes known as the Ash Borer, is a clearwing borer moth that creates tunnels in lilac stems.
- Frass, sap, and sawdust are warning signs (excrement).
- Some plants can withstand this harm.
- Others see branch dieback, and occasionally the entire plant dies.
- They won’t likely catch anyone’s attention.
Jeff Hahn, an extension entomologist, confirmed that no lilac borer samples have entered his lab this year.
Herbicide damage
Broadleaf weed treatments on lawns may volatilize, changing to a gas, and float onto unintended plants if sprayed during periods of extreme heat and humidity.
Herbicide damage signs like cupping and browning would appear in patterns:
- along a hedge’s one side but not the other,
- bushes positioned in or close to lawn areas, at the same level throughout their bases,
- and most critically, away from the area’s predominant winds.
Lilac hedges next to agricultural fields or other sizable herbicide-treated areas may experience damage in this manner.
Do lilacs ever stop blooming?
It hasn’t been trimmed or kept up with in more than five years. If the majority of the wood in your lilac is older than that, the quantity of blooms will be reduced because lilac bushes bloom best on younger wood, which is 5 or 6 years old. The bush needs to undergo rejuvenation pruning.
How can you prolong the life of lilacs?
Lilacs are a nostalgic flower for many individuals. On our property in Kansas, my mother planted a lot of lilac bushes. As I played, the aroma spread across the yard. In order for our children to share the same exquisite recollection of the aroma and flower, my husband and I made it a priority to plant a lilac in our garden when we first started our family.
I’ve tried, and have failed, through the years to bring this flower’s bounty into my house. Even though I had the flowers in a spotless vase filled with new water, they would begin to wilt an hour after I brought them inside. I have figured out how to make the blooms last as long as possible by trial and error:
As you trim blooms, have a pail half-full of fresh, chilled water nearby. Choose a chilly morning or evening to pick flowers. Lilacs bloom very sporadically after being harvested, so look for stems with at least 75 percent of their flowers open. Next, remove all of the leaves to prevent the plant from exerting extra energy to keep them moist. Put stems in the liquid. Allow the flowers to absorb water in the bucket for at least an hour by placing it in a cool, dark location.
Recut the stem ends next with powerful clippers, then make 1-2 inch vertical slices up the stem. Take hold of the sliced stem’s one side and twist it backward. Reintroduce the chopped stems to the water in the bucket right away. For an additional hour or two, let the stems soak up extra water in a cool, dark location. After that, the lilacs will survive three to four days and be ready for arranging.
Can I cut my lilacs all the way down?
The lilac tree will resemble nothing more than a twig in the garden by the end of September. It shouldn’t be reduced to the ground, though. Despite the fact that lilac trees are known for their resilience, it will likely take several years before you see blossoms again because you cut off all the blossoming growth.
If your lilac tree is more mature and unruly, it may require more aggressive pruning and some chopping back; just make sure that it doesn’t take up more than a third of the tree.
If cut, will lilac bushes regrow?
It’s crucial to know when to prune lilac bushes. Most lilacs don’t need to be pruned until they are between 6 and 8 feet (2 and 2.5 meters) tall. Lilac plants should be pruned as soon as the flowering is finished. This gives new shoots plenty of time to grow before the upcoming blooming season. Lilacs can lose young, budding buds if they are pruned too late.
Early spring is the ideal time to prune lilac bushes or shrubs completely to a few inches above the ground. As long as there are still a few healthy shoots present, new shoots will continue to grow throughout the normal growing season. Remove any ugly shoots when the growing season is finished.
Lilac bushes’ health and bloom output depend on regular pruning. Lilacs are typically quite hardy, and with the right pruning, they will grow back bigger and better than before.
What destroys lilac bushes?
A common chemical component of broad-spectrum herbicides is glyphosate. This poison will enter the living cells and start killing the roots when applied to the open wounds on the lilac stumps. One hour after trimming the exposed growth is the ideal window of opportunity to apply glyphosate. Check the area for the appearance of tiny, thin suckers that also need to be treated while spraying the glyphosate to the stumps that were clipped. At least 24 hours are required for the glyphosate to start acting. Rain or watering before this period will wash the chemical away and reduce its potency.
When do lilac bushes need to be pruned?
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.
How can you assist a lilac in need?
Lilacs require full sun, or around six hours of sunshine each day. Make sure that no other trees are blocking your lilac’s sun so that it can thrive even in partial shadow.
Mulching around your lilac plant prevents the roots from drying out and aids with weed control. It’s crucial to routinely water lilacs in dry weather. Lilacs, however, prefer well-draining soil and dislike damp, moist roots.
Stop fertilizing your lilac if it isn’t flowering. Lilacs that have received excessive fertilization will produce an abundance of lush growth but not the desired amount of flowers. Lilacs don’t need a lot of fertilizer, perhaps only a modest feeding in the spring. Your lilac can be receiving more food than it needs if you routinely fertilize adjacent lawns or other plants. Your lilac’s soil will benefit from having phosphorus added, such as by using bone meal.
Scale insects and borers can harm lilacs. Check the leaves and stems of your bush to see if a renewal pruning is necessary. Usually, removing the problematic regions will solve the issue.
Are lilacs suited for coffee grounds?
Lilac plants don’t require a lot of food or fertilizer. A 10-10-10 fertilizer mixture applied yearly in the early spring is what we advise. (The amounts of nitrogen, phosphorus, and potassium, or NPK as they are popularly known, are represented by the digits 10-10-10 in the formula.) Early spring fertilization of lilacs with a high phosphorus solution encourages blossoming.
Coffee grounds and grass clippings are also excellent sources of nitrogen. Use in moderation since an excess of nitrogen in the soil can lead to subpar blooms. The ideal soil conditions for lilacs are slightly alkaline (6.5–7.0 pH), wet, and well-drained. The soil may become more alkaline by adding bone meal to it. Use Miracle-Gro Shake ‘n Feed Flowering Trees & Shrubs Plant Food in the spring if you decide to feed your plant. Last but not least, lilac plants dislike acidic soil. Epsom salts can be used to encourage blossoming while the plant is dormant.
Are male and female flowers required for lilacs?
Abiotic and biotic methods are both used to pollinate lilacs. When a pollen sac travels from the stamen to the pistil with the help of an active pollinator, such as a bee, butterfly, or bird, this process is called biotic pollination. Abiotic transportation is made possible by the wind, the rain, or other natural occurrences. A pollen tube develops when the pollen sac touches the stigma of a female flower. The tube enters the ovary through the style. When a lilac plant has both male and female flowers, it can self-pollinate. It can also be cross-pollinated if there is another lilac bush nearby, which occurs when a pollen sac from one plant lands on the stigma of a flower from another plant.
Lilacs bloom twice a year, right?
Compared to other lilac trees, bloomerang lilac trees are more compact, reaching a short height of 4-6 feet tall and a spread of 4-6 feet, giving them a pleasing, rounded appearance. Their long, arched branches bear their veined leaves, which are bright green for the majority of the year until turning yellow in the fall.
The characteristic 4-petaled, 4-6 inch deep lilac-purple blooms on bloomerang lilac trees appear starting in May, cease blooming in June, and then return in July through the first frost of the year.
Specifications
With tall, arched branches, a compact and rounded shape, and rich green foliage that turn golden in the fall. Four spread petals, 4-6 inch, lilac-purple flowers that bloom in the spring and later in the summer.