Red pine’s problems traced to lack of diligent watering

Last week, while we were pruning a crabapple, Ellsworth Master Gardener Dan DeLong told me about a friend who removed the burlap winter wrap from a young red pine to find the needles brown, falling off. Another horticultural mystery to solve! What could have caused the demise of his friend’s small tree? Our discussion went something like this:

“He unwrapped the tree and all of the sprills had turned brown.” Sprills? I had never heard this word and asked Dan if he was referring to the needles. He was. “The terminal buds seem alive, although some are not very green.”

I took a minute to think while snipping a watersprout off a branch of the crab. “I don’t think its winter damage. Red pine is native here and farther north, a Zone 2 tree, I think. It would have no problems with the coldest Maine winter. And your friend had it wrapped, good protection from desiccating winter winds. How old is this tree? When was it planted?”

“A year or two ago, I think,” Dan replied as he swapped pruners for loppers. “It’s still a young tree.”

I paused to think about which of two crossing branches to remove. “My guess, Dan, is that this has little to do with winter. It could be a disease called needle blight, or it could be a water stress problem related to our recent droughty summers. We’ve had four or five dry summers in a row. A newly planted tree, if not watered regularly, would have a limited root system. It would grow very slowly and be unable to maintain healthy foliage, particularly during severe drought. Do you know if your friend watered his tree regularly after planting?”

“I think you’re on to something. He planted the tree on ledge with very shallow soil. And I don’t think he watered regularly. Yes, I think you may be right,” Dan said, as he made the final cut. We both stepped back from the crabapple to admire our work.

We often blame winter for the insults and injuries of previous summer drought and for our neglect during the establishment period, the length of time, measured in years, that newly planted trees (or shrubs) need to replace absorbing roots that were lost during nursery production, harvest and transplanting. Researchers tell us that, in general, the establishment period is one year for every inch of trunk diameter at planting. During this critical period, the entire rooting area of a tree should receive 1 inch of water every week during the growing season, if not from rainfall then from irrigation.

Back to Dan’s friend and his red pine. I suspect that lack of regular watering during the establishment years led to a limited root system. The resulting water stress caused a slow decline in the tree’s health, possibly weakening the tree’s resistance to disease, certainly limiting its ability to maintain healthy foliage, even in the absence of disease. The tree may still be alive, but it may be too late to rescue the tree from a slow but certain death. Rather than attempt such a rescue, Dan’s friend should replace the tree with another and plan on watering it regularly during its establishment period.

Send queries to Gardening Questions, 116 N. Main St., Orono 04473, or e-mail

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Plant small trees!

Understanding the importance of the establishment period provides a strong argument for planting small trees. Consider two trees of the same species with trunk diameters of 1 inch and 6 inches, respectively. Ten years after planting, they are the same size! This is because the smaller tree, its root system established after only one year, grew more rapidly in the subsequent nine years. It took six years for the larger tree’s root system to become established, giving it only four years of rapid shoot growth.