By Sharon Omahen & April Reese
University of Georgia
When homeowners
call University of Georgia plant pathologists for
help with diseased Leyland cypress trees, they usually aren’t
happy with the advice.
The state’s recent deluge of rain is taking a toll on one
of the
most popular landscape trees around. Leyland cypress are being
hit hard by disease as a result of too much water.
There’s no cure
“Once a Leyland cypress becomes diseased with root rots, there
is
nothing you can spray to cure it,” said Mila Pearce, an
integrated pest management specialist with the UGA College of
Agricultural and Environmental Sciences.
Pearce works closely with UGA Extension Service county agents
to
identify submitted disease samples and make recommendations to
homeowners.
Due to Georgia’s unusually soggy summer, she has been
answering a
lot of calls about Leyland cypress trees.
“Leylands don’t like wet feet, so they don’t like wet
weather,”
Pearce said. “And with all of the rain we’ve had this year, the
conditions are right for needle blights and vascular diseases as
well.”
Preventative measures
There are some things you can do to prevent diseases from
taking
over your trees.
“You can prune the branches to try to get air flowing through
the
trees,” she said.
Pearce also suggests cutting away diseased sections of the
tree.
“If you see a diseased spot, cut six inches below where you
see
the symptom and discard that piece,” she said. “After all, it is
better to sacrifice a branch than loose the whole tree.”
If the disease has reached the tree’s trunk, Pearce says, it’s
just a matter of time before the entire tree is lost.
Fungicides can be used as a preventative measure on healthy
trees.
Pearce recommends using Mancozeb,
Cleary’s 3336 or a Bordeaux
Mixture spray. Just follow the directions on the container.
“If your neighbors’ Leylands are doing poorly and are
diseased,
get ready,” she said. “With all of the rain we’ve been having,
it (disease) can easily cross the street.”
A healthy plant begins on day one
Consumers can help keep their Leyland cypress trees healthy
from
day one, says Alfredo Martinez, UGA Extension plant pathologist.
“Leyland cypresses are marketed as a relative low-maintenance
landscaping trees,” Martinez said. “But consumers should not
confuse low-maintenance with no-maintenance.”
All trees need to be cared for, whether you are applying
fertilizer, watering correctly or planting properly, he said.
Martinez recommends planting Leyland cypress trees at least
eight
feet apart, measuring from the center of the tree. The trees
should also be planted in an area that provides good drainage.
When planting, make the hole big enough and loosen the dirt,
especially if you are planting in clay soil.
“You should dig a $5 hole for a $1 plant,” Martinez
recommends.
“In other words, dig a hole at least three times the size of the
plant’s root ball and refill the area with loose soil to help the
roots and tree get established.”
Cypress trees have shallow root systems and Georgia clay
doesn’t
drain fast enough to keep them dry, Martinez said.
“Too much rain can drain out nutrients such as nitrogen,
phosphorus and potassium into the soil and also leaves the roots
in a puddle of water,” he said. “This causes the tree to be
stressed and makes it prone to root rot disease.”
With the amount of rain our state has had over the past month,
Martinez says he has seen Leyland cypress trees turning yellow
and dying in a matter of weeks. He has also seen Leyland cypress
trees actually tilt from their original planting spot and expose
their roots atop the soil in flooded sites.
