Leyland cypress trees, with the scientific name Cuprocyparis leylandii, are fast-growing coniferous trees often used for hedges and boundaries. These evergreens are popular for their slender, pyramidal shape, and can grow as high as 60 or 70 feet. However, like most plants, they are also prone to diseases and conditions that can weaken them, and possibly even kill them, if not addressed in time.
How to save a dying Leyland cypress tree
Check the soil drainage around the tree
If you suspect your Leyland cypress is dying, carefully check the soil’s drainage. These trees thrive in well-draining soil, and if they are not planted in such soil, they are more likely to be afflicted by cypress diseases. Plant the tree in well-draining soil while it is still young.
These trees grow well in slightly acidic, loamy soil. If the soil is compacted, organic matter may be added. This will enrich the soil with nutrients and discourage the growth of weeds.
A raised mulch bed may also be made to improve soil structure and conserve moisture. Compost manure can be added to fertilize the soil.
Plant the tree where there is full sunlight
Leyland cypress trees need at least eight hours of sunlight daily to grow well. Be sure that they are positioned in open spaces where they can soak up the sun. If they are planted in shady spots, it is possible that they won’t grow well and may die.
Potted trees should not be placed indoors since they won’t have access to full sunlight. Place them outdoors so they can get good air circulation and plenty of sunlight. Remove any taller plants near your Leyland cypress that could be blocking the sun.
Examine the tree for possible diseases
Diseases usually develop when the trees are over- or underwatered, or if there is poor air circulation. Any of these factors will weaken the trees and they will become more prone to pathogens that bring diseases.
Common diseases of Leyland cypress trees include the following:
- Canker or Seiridium canker – This fungus attacks tree bark and turns the leaves yellow while slowly killing the tree. To detect this fungus, check the bark for cracks, where the fungus attacks. To treat the tree, cut off and get rid of all infected branches. If the fungus has already attacked most of the tree, you will need to dispose of the entire tree at once to prevent the spread of disease.
- Phytophthora root and crown disease – This is caused by soil-borne fungal pathogens of the Phytophthora species. It is characterized by red or yellow, wilted leaves. Revive your tree by removing the infected barks, or with the use of fungicides.
- Needle blight – This non-parasitic disease is caused by incorrect watering techniques, either through under- or overwatering. The leaves will turn brown and the roots become damaged. Revive the tree by providing it with the correct volume of water and use an anti-fungal spray to eradicate the disease.
Inspect for insect infestation
Insects and other pests can kill Leyland cypress trees. Common insects that attack these trees include bagworms and spider mites. Bagworms lay countless eggs that hatch into caterpillars, which form silk bags. These numerous bags could damage the tree unless you take prompt action, so apply pesticides as soon as you can and remove the silk bags by hand.
Spider mites attack trees by sucking the sap from the plant’s cells, killing the foliage and destroying the trees. The leaves may also turn brown. Use insecticidal soap, high-pressure water and pesticides to eradicate these pests.
Make sure you are watering correctly
If young Leyland cypress trees are not provided with enough water to grow well, they could become weak and possibly die. Take extra care to provide enough water for your trees during their growth stage. Keep in mind that too much water could lead to root rot, while a lack of water will cause the leaves to turn brown, followed by dehydration of other plant parts.
Young trees should be watered to at least three inches deep. The initial watering should be three times a week for three weeks, after which the watering may be reduced if the roots are established. If the plants are still showing signs of stress, apply fertilizer in early spring, before the late spring dormancy period.
Mature trees are drought-resistant and their soil should be allowed to dry out between waterings. Water should penetrate at least 24 inches into the soil to ensure that the root balls are properly soaked.
Leyland cypress trees are fast-growing conifers that are popular as hedges and in landscapes. They are also prone to problems and diseases, but they can be saved from death if treated promptly and correctly. Make sure you support the overall good health of your tree by watering correctly, providing adequate sunlight and drainage, and inspecting regularly for the presence of diseases and pests.
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