In late February, tree lilacs had begun to leaf out and there were already a few corneliancherry dogwoods
blooming at Simpson Garden Park in Bowling Green.
One week later, crabapple trees started breaking bud.
The mild, wet winter of 2017 has most plant and insect activity well ahead of schedule.
What does this mean for home landscape in the upcoming growing season?
A lot of plant and insect activity is closely associated with temperature. The mild February weather led
to leaf and flower buds swelling and in some cases already breaking bud. The early start puts these
plants at risk to a sudden cold snap.
Trees and shrubs do not develop cold hardiness as quickly as they lose it. A sudden cold snap would
likely severely damage tender flower and leaf buds.
They generally will leaf out again if leaf buds are damaged. However, flower buds, once damaged, will not
reform. A sudden cold snap in March or April could mean fewer flowers this spring.
Sudden cold usually will not kill a tree or shrub hardy to our region unless it has just begun to grow.
In some cases trees and shrubs are severely damaged or even killed during these events.
While living near Akron, I witnessed a number of lilacs killed by a sudden cold snap in April 2007.
The Colorado Front Range is known for some extreme temperature fluctuations.
I have seen some trees not leaf out until June following an extreme spring cold snap.
Many people expressed concerns about crabgrass germinating. Crabgrass does not germinate until the
average daily soil temperature is between 57 and 64 degrees at a one inch depth.
Soil temperatures need to reach 73 degrees before large quantities of crabgrass are germinating.
As of March 7, the Ohio Agriculture Research and Development Center shows the average soil temperature in
Pemberville in the upper 40s. Most crabgrass control options provide extended control but it is still
important not to apply them too early.
The mild weather also impact when different insects become active.
One way to stay ahead of insects is to use Ohio State University’s phenology and growing degree day
calendar.
The Buckeye Yard and Garden online newsletter indicated that Cincinnati had already accumulated enough
growing degree days by late February that eastern tent caterpillars would begin hatching. Previously,
their earliest observed hatch there was mid-March.
While pruning trees this winter I’ve noticed gypsy moth egg masses on mature oaks and a lot of scale on
young trees.
The insect pests vary from landscape to landscape and it is a good idea to regularly scout your landscape
to find them and monitor their activity.
While not weather related, oak wilt is an increasing concern in Northwest Ohio. There were several
suspected cases last summer in Lucas County but fortunately none yet in Wood County.
Oak wilt is a threat to all oaks. Trees in the red oak group such as red, black, and pin oaks are
especially vulnerable and can die within several weeks of symptoms developing.
It is a complex disease and spreads several ways.
However, one of the easiest steps to help reduce the chance for oak wilt spread is to adjust pruning
practices.
OSU Extension recommends avoiding pruning oak trees during the growing season in areas where oak wilt is
present.
(Jones is the arborist for the City of Bowling Green.)