Sure, water is good for your trees in Massachusetts. But just like too much candy can give you a tummy ache, your plants can receive too much of a good thing.
In fact, Massachusetts is one of the wetter states with an average annual rainfall of 48.5 inches, according to Best Places. Its wettest month is March with 4.5 inches of rain, while May typically has the most days of rain with an average of 12. Throughout the year, Massachusetts usually experiences about 124.9 days of rain.
Is a rainy season bad for trees? It can be. Just like excessive rains might have you shouting, “Rain, rain, go away,” your trees might be wishing they could say the same.
A lot of rain can impact nutrient and oxygen levels in the soil, not to mention increase potential for fungal diseases.
Let’s talk about what happens to plants during a wet season and the impact of a wet season on trees so you can learn what to do to safeguard your landscape. While a certified arborist can make specific recommendations based on which plants you have, there are certain things you can check for to determine whether your trees have received too much water.
Check The Soil Conditions
After a longer period of rain or heavy storms, the first step would be to check your soil conditions.
You want to look for water pooling in low spots or where drainage isn’t flowing properly. If you have trees or shrubs located in these areas, they could be suffering from a lack of oxygen to their roots, as well as nutrient deficiencies.
What is the impact of a wet season on trees? Trees that prefer dryer or well-drained soils, such as spruce, will be more at risk of adverse conditions. What you might see are symptoms of overly saturated soil, such as wilted, yellow or falling leaves or needles. Any heaving of the soil around a tree is also not a good sign.
Leaf yellowing can be caused by any number of factors besides waterlogging such as nutrient deficiency. A soil test can help determine if the cause is related to nutrient deficiency. Working with your certified arborist to get a soil test can show you what nutrients your tree may be lacking and guide you on which type of fertilizer is necessary to restore your tree’s health.
Don’t Ignore These Physical Symptoms
What happens to plants during a wet season is that the soil can become waterlogged. This can slowly starve the tree of its access to air and nutrients and lead to root rot.
It can also result in rapid disease development. This is particularly true for trees that are already stressed or in poor health.
If you have trees that have this tendency to suffer from disease, especially after wet periods, having a certified arborist preventively treat them for foliar disease is a good idea, as well as providing regular care to maintain tree health.
Watch out for the following visual symptoms that may reveal the impact of excess rainfall on trees and shrubs.
Look at the Leaves or Needles
With the wet conditions in Massachusetts last year, you may have noticed the uptick in foliar diseases on your trees.
One of these is called anthracnose, which results in leaf spots on trees like sycamore. Phytophthora also thrives in wet conditions, revealing itself with wilted and browning leaves on susceptible species. You can also find that evergreens suffer the impact of a wet season on trees, resulting in needle yellowing or browning. Not only can these diseases make your trees unsightly, but they can also be devastating over time, leading to defoliation. Excess rains can bring more disease spores, particularly if diseased leaf litter is also accumulating on the ground.
What are the effects of a wet season? If you have trees in your home landscape that have experienced foliar disease issues in the past, monitor them closely through concurrent rainy periods.
Other Concerning Signs of Trees Suffering After a Wet Season
In addition to looking at your tree leaves or needles as you’re investigating what happens to plants during a wet season, you might notice some other signs.
Check for fungal fruiting bodies – otherwise known as mushrooms – on the ground near the base of your tree. While many of these mushrooms can be harmless, they can be pathogens. Having a certified arborist with the ability to properly identify these can ensure your tree is safe. Never ignore fruiting bodies on the tree itself because they can signal tree decay.
If the tree wood itself looks dead or breaks easily, this is also an impact of a wet season on trees.
Stressed trees from excess water can also begin looking yellow or lime green in color. This is called chlorosis, and it is a classic sign of overwatering.
Finally, don’t forget to check tree roots. If you see a shift of the tree’s root plate where your tree begins to lean, or if the roots lift out of the ground on one side or seem to create a soil bulge, have a certified arborist immediately examine the tree. This could be a safety issue where your tree is at risk of falling.
Evaluate & Adjust Irrigation Systems
As you head into spring, it’s also important to take a look at your irrigation system.
Why and how can a changing climate affect tree health? You don’t want to be adding additional water to the already saturated ground. Even if you’re used to turning on your irrigation system in spring, that doesn’t mean you need to run it just yet if Mother Nature is delivering too much moisture.
Have a professional audit your system and adjust it, taking into account the rainfall. This can help you ensure you’re not only saving water and money, but also only delivering the supplemental irrigation that your trees need.
Remember, Tree & Plant Issues May Appear Later
Just because you suffered a wet year and saw no immediate signs of concern doesn’t mean you shouldn't watch out for the impact of excess rainfall on trees and shrubs.
First of all, a wet year last year doesn’t automatically mean your trees will have fungal issues this year. And while spore loads may be higher locally, most fungal pathogens will need a wet spring in order to actually infect new tissue. This is why we often see diseases fluctuate in severity from year to year.
On top of this, the fairly mild winter can potentially make things worse.
Consulting a certified arborist can show you what trees are most at risk on your property so you can reduce your worries and get back to enjoying the many benefits your trees provide.
At Hartney Greymont, we have both ISA and Massachusetts certified arborists located in Needham, Concord, Danvers, Cape Cod, and the surrounding areas who can help assess your tree health and determine if a wet season has brought about any concerns.
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