Hotter than normal spring creates problems for plants

by Gene Sumi

Leaf scorch on maple tree

I have just finished reading the weekly report on plant and pest activity in Maryland from the University of Maryland Extension, and read their first comment about the recent hot weather.  They stated that we just moved from a cool, wet to a hot spring in the past week, with temperatures rising into the 90’s.  Reminds you of last year about this same time period, doesn’t it?

Obviously, this is an unusual weather pattern for us.  It is also abnormal to many of the plants that we grow in our region of the country.  One of the problems is that newly produced leaves on trees and shrubs are still relatively tender and this high heat has caused leaf burns on their upper surfaces.  Customers have brought some of these leaves to us here at Homestead Gardens.  For example, a person brought in leaves from a maple tree that had scorch marks that looked just like someone had passed over them with a hot iron.  This caused considerable leaf drop by the tree and much concern to the tree’s owner.  But I pointed out to him that new leaf buds had already formed to replace the leaves that have been damaged and had fallen on the sample branch he had brought in to show us.

This is one example of the recent rush to our Diagnostic Center by people with many early signs of insect pest activity, which have appeared about a week earlier than normally expected, because of the hot weather.  Normally, you would plan to address these problems when they typically occur on the calendar, but when they get a jump on us, we need to react.  Like many things in life, things that happen earlier, and not addressed then, often come back to haunt you later.   There is a lot to be said about “nipping the problem in the bud”.  We should then try to control pests that threaten our beloved plants by killing off that very first generation that hatches in the spring, before it can increase their numbers by being allowed to produce new generations.   Killing insects before they are mature enough to produce new insects, like killing weeds before they are mature enough to reseed, is a logical way to hold down the pest problems you find now, as opposed to what you will have to face this summer if you let it go.  This also goes for plant disease, as most disease controls do a much more effective job when they are used to prevent the fungal or bacterial diseases, or if they are used at the first signs of infection on the plants.

For more information about plant problems, bring samples to the Homestead Gardens Diagnostic Center, or click here for help from the University of Maryland.  Photo credit:  Missouri Extension Service.