I give a lot of presentations on a variety of garden topics to all kinds of groups and organizations. I always leave a little time at the end for questions. Invariably there is a question about a pine or a spruce problem.
Just last week I was at the Columbus Home and Garden Show as part of a panel of experts, answering gardening questions. A gentleman in the audience asked a question about his pines and spruces. A few of the pines were starting to turn brown from the bottom of the trees up.
Recently, I visited a Christmas tree grower who had several Scotch pine trees exhibiting the same symptoms.
When it comes to diagnosing problems with pines and spruces, it can be somewhat challenging.
Most often the culprit that is causing the slow decline and eventual death has to do with the fact that these trees are not native to Ohio. In addition, they really don’t like heavy clay and poorly drained soils.
Eastern white pine is native to Northeastern U.S. down through the Appalachians toward the south.
Scotch pine is native to Europe and was brought to the U.S. primarily for Christmas tree production.
Scotch pine has actually naturalized in parts of New England and the lake states.
Norway spruce is native to Europe.
Blue spruce is native to the central and southern Rocky Mountains.
All of the above are the most common evergreens that we like to use as screens or as a specimen landscape plant.
Let’s get back to the issue of these plants turning brown. There are some diseases that affect these plants, or it may be insect pests causing the problem.
The first step is to rule out a living organism that might be causing the problem. If we can eliminate that as the source of the problem, we then turn to the root system.
When these evergreens turn brown, we know that it doesn’t usually occur overnight. It might be the result of several years of unhappy root systems.
We tend to have extreme conditions: really dry and hot or really wet for a prolonged period of time (like this past June/July).
When these evergreen roots are subjected to these extremes, they aren’t happy. And they are usually growing in clay soil (sometimes compacted clay soil). Some die.
As plant roots die, the top starts to show signs of decline. When this occurs, there is nothing that you can do to fix the problem. Once a tree starts to turn brown uniformly, especially if it’s from the bottom up or top down, it’s likely on its way out the door.
The best control option is prevention. Plant these evergreens in well-drained soil and pay attention to watering during times of drought. Keep them as healthy as possible to keep them living as long as possible.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at firstname.lastname@example.org.