You might believe your lilac is dying if you see it becoming a little frail or worn out, or if it only produces a few little flowers in the spring. Often, all a plant needs to produce robust new growth and abundant, fragrant blossoms is some hard pruning and some feeding. Rejuvenate a lilac bush by working with it just after bloom, when the blooms have dried up and are spent.
To get to the grass or soil layer, rake away any debris, dead branches, or fallen leaves from the lilac’s base.
Pick three to five of the lilac’s strongest branches after surveying the entire plant. Follow the branches you’ve chosen to the plant’s base, where you can flag each sturdy branch by gently tying a rope or ribbon around its base.
Use hand pruners or a handsaw if needed to make a clean, horizontal cut across all of the unflagged branches that are about an inch off the ground. To prevent breaking off any limbs you want to maintain, carefully pull the trimmed branches away from the lilac.
- You might believe your lilac is dying if you see it becoming a little frail or worn out, or if it only produces a few little flowers in the spring.
From the remaining branches, take off your sting or ribbons. Fertilize the lilac around its base according to the dosage and application guidelines provided by the manufacturer.
Mulch should be applied in a ring around the lilac’s base that is no deeper than 3 inches and no wider than 3 feet. New sprouts won’t be able to emerge if the mulch is too deep.
If there is a drought or excessive heat in your area during the summer, make sure the plant is well-watered. Lilacs require good drainage, but they don’t fare well in dry soil.
The next spring, watch for buds to start swelling on the branches. Reapply fertilizer right before flowering and once more after flowering is finished. This is how you should fertilize each year.
- From the remaining branches, take off your sting or ribbons.
- The next spring, watch for buds to start swelling on the branches. Reapply fertilizer right before flowering and once more after flowering is finished.
Maintain your lilac by doing minimal annual pruning to remove wasted flowers and only every three to five years to remove old and dead branches.
Avoid letting the feed come into contact with the branches when applying fertilizer to the area around the plant, whether it be granular or water-soluble.
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.
How can I fix my lilac bush?
Lilacs are a sturdy group, yet they are susceptible to issues just like any other landscaping shrub. Keep an eye out for these illnesses:
Infection blight
Early shoot and branch dieback, deformed leaves, and leaf spots that start out olive green but quickly turn into water-soaked patches are all brought on by the bacteria Pseudomonas syringae. These areas start to deteriorate and turn brown with yellow edges. Blossoms may abruptly grow limp or turn brown. The easiest strategy to control this illness is to remove the infected material and thin out the shrub’s interior, but if it has spread widely, a copper fungicide will hasten its demise.
a powdery mold
The most frequent issue with lilacs is most likely powdery mildew. It is brought on by a number of fungal diseases, which make the leaves to look powdery, either in discrete areas or all over the surfaces. The best therapy is increasing airflow around sick leaves, so thin your plants annually.
Leaf spotsLeaf spots are another fungus issue that can be brought on by numerous infections. You probably have one of the various leaf spot diseases on your hands if you notice tan spots developing on your lilac leaves, whether or not this results in the leaves falling. This issue, like powdery mildew, is brought on by excessive local humidity; therefore, thin out that shrub and clear away any fallen debris to stop more infections.
Is it possible to revive a lilac bush?
A: There are a number of potential causes for your lilac’s failure to bloom. The two most frequent culprits are insufficient sunlight and poor pruning. Lilacs (Syringa) should be planted in an area with at least six hours of direct, bright sunlight per day. They can withstand a wide range of moisture levels as long as they are grown in soil with good drainage. If your lilac is clipped at the wrong time of year, it might not blossom for another reason. Lilacs bloom in the spring on the growth from the previous year, and soon after, they begin to form the buds for the following year. Within a couple of weeks of the plant blooming, pruning must be done in order to prevent the removal of the buds for the next year. You can softly clip young lilacs to keep them in check, within boundaries, and flowering profusely. In order to revitalize older plants and increase flower production, a rigorous pruning almost to the ground may be necessary. A late freeze can harm flower buds on types that bloom early.
Lilacs have a tendency to mature into overgrown, leggy shrubs with minimal foliage at the bottom. When this occurs, it might be required to prune them to within 12 inches of the ground in order to completely rejuvenate them. When the shrubs are dormant in late winter, this should be done. Lilacs benefit from this repair, although their blooming cycle will be hampered for at least one season. Lilacs can receive a rejuvenation pruning over a two-year period to stop the interruption of bloom cycles. One year, hard prune half of the shrub’s stems; the following year, hard prune the remaining stems.
Lilacs do not consume a lot of food. Excessive fertilization, particularly nitrogen fertilizer, can frequently promote luxuriant vegetative growth at the expense of flower development. The number of blossoms won’t increase with fertilization. A lilac’s failure to bloom could potentially be due to its proximity to turf that receives frequent fertilization.
How are lilacs brought back to life?
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.
What does a lilac tree that is ill look like?
Yellow, tiny, and deformed leaves are possible. The broom-forming twigs are unusually erect, frequently keep their green leaves on for too long in the fall, and then they wither away in the winter. Remove any damaged branches. Remove plants that are seriously affected.
How is a sick lilac tree treated?
Portland, Oregon – Do the fresh blooms and branches on your lilac plant resemble burnt wood from a blowtorch? Lilac blight is a bacterial plant disease that could affect your bush.
Lilac blight is more likely to occur in a cool, wet, rainy spring, especially if there has been a late frost or other winter damage. Plant pathologists at Oregon State University Extension are cautioning that this year may be favorable for the disease.
Lilac bacterial blight, as the disease is officially known to plant pathologists, is brought on by the bacterium Pseudomonas syringae pv. Syringae. The bacterial blight that affects pear, blueberry, cherry, maple, and many other woody plants is caused by the same organism, and the symptoms of lilac blight resemble those of fire blight in fruit trees.
Initially, leaves appear to be in full health, but a short while later, they appear to have an open flame nearby. Young shoots with dark black stripes on one side demonstrate the disease’s progression. Unopened flower buds turn black and the blossoms fade, turning brown.
Never fertilize after the growing season has ended. Don’t fertilize young plants excessively.
Lilac blight is challenging to eradicate, therefore anytime you plant new lilacs, it is advised that you use blight-resistant kinds.
In order to prevent friction and allow air to easily circulate between the plants, it also helps to space and clip your lilac plants. Never fertilize after the growing season has ended. Melodie Putnam, an OSU Extension plant pathologist, advised against overfertilizing young plants since excessive nitrogen levels encourage the development of diseases.
If your lilac bush does have an infection, immediately cut and burn all affected areas. A copper sulfate spray applied in the early spring each year should help stop the issue before the buds start to open.
In order to prevent friction and allow air to easily circulate between the plants, it also helps to space and clip your lilac plants.
Bacteria that cause lilac blight can overwinter on good wood or sickly twigs. Plants are more susceptible to the illness when they are weak or injured by factors such as wounds, frost damage, soil pH, inadequate or poor nutrition, and infection by other diseases.
Old cankers, healthy buds, leaf surfaces, and adjacent weeds and grasses can all be sources of this disease. The bacteria were dispersed by wind, rain, insects, tools, and diseased nursery stock.
In western Washington, some lilac species, including S. josikaea, S. Komarowii, S. microphylla, S. pekinensis, and S. reflexa, have demonstrated resistance. The majority of S. vulgaris cultivars are prone to the illness, however others, like “Edith Cavell,” “Glory,” “Ludwig Spaeth,” and “Pink Elizabeth,” have been seen to be less afflicted when grown in gardens. Be aware that ‘Ludwig Spaeth’ is quite vulnerable in systems with large nursery production.
If your lilac bush does have an infection, immediately cut and burn all affected areas. Early in the spring, apply copper sulfate to the ground.
As young shoots form in the early spring, the disease first appears as brown blotches on their stems and leaves. The area may also have a yellow halo surrounding it. Especially when it rains, spots quickly turn dark and spread out. The age of the plant component that was damaged determines how far the infection can spread.
On immature stems, the infection encircles and girdles the stem, causing the shoot to crook at the lesion and the sections above it to wilt and die. On mature wood, lilac trees do not get infected; only cherry trees do.
Young, infected leaves quickly become black, first at the margin and then down to the petiole in a wedge-shaped pattern. The leaf eventually withers completely. Spots on older leaves slowly grow. The margin or the mid-vein of the leaf may crumple when numerous areas occasionally run together. Additionally, flower clusters may become diseased, quickly blighted, and darkened. Buds may not open properly or they may turn black and die soon after they do. The signs are the same as those of a winter injury.
Visit the PNW Plant Disease Management Handbook of OSU Extension to view pictures of this disease. The guideline reiterates the following cultural restrictions on treatment:
- Maintain proper plant spacing and prune to encourage proper airflow within the canopy.
- Cut all afflicted tissues out and burn them right away.
- Plant species or cultivars that are resistant.
- Never fertilize after the growing season has ended. Don’t fertilize young plants excessively.
Do you want to know more about this subject? View further materials from OSU Extension here: