This article is the third in a series about Leyland Cypress.
If you have missed any of the other articles and are interested, please go to
possumsupply.com and look under the Horticulture Hotline tab.
Phytophthora root rot is a disease that attacks the root
system of plants and ruins the roots where they cannot absorb water and
nutrients; therefore, killing the tree. If you had a very high dollar tree and
you wanted to spend a lot of time and money, you could possibly save a tree
from Phytophthora; however, it would be cheaper and easier to replace the
Leyland Cypress with a plant that is not susceptible to this disease.
Phytophthora is a disease that does well in wet, poorly
drained soils. Most plants like well drained soils. If you are going to
replant, treating the area with a product labeled for Phytophthora, correcting
the drainage and increasing the good fungi in the soil that will compete with
Phytophthora (good organics) would be a good idea.
The canker diseases and Phytophthora are the killers. The
needle blight just leaves you with an ugly tree – dead from the bottom up. I
have a friend with a Christmas Tree Farm that is constantly battling these
diseases. If the diseases were not enough, insects and mites love these trees
as well.
Mites are what I encounter the most. Mites seem to like hot,
dry weather. Mites are very small, but with a “beat sheet” you can find them. A
Leyland Cypress has layered limbs so it makes this very easy (you can do this
with any plant – I started using this method a long time ago while working with
cotton). Just place a white sheet of paper between the layers of limbs and slam
the limb above the sheet down onto the sheet. If you have mites, you will see
these very small creatures running around on the paper.
I like using neem oil, horticultural oil or insecticidal
soap to control them because they will also help control scale, another pest
that attacks Leyland Cypress.
Bagworms also attack Leyland Cypress. They are easy to see
and you can pull them off by hand. Bt, a bacteria insecticide, works great if
you catch them while they are young.
After writing about Leyland Cypress issues for three weeks,
I would consider another tree if I was planting a new tree. Many hollies would
have similar form and not near the issues.
Bt also works great on mosquito larvae. With all this rain,
I’m seeing a lot of fungus and mosquitoes.
Always read, understand and follow product label. The
product label is a Federal Law.
