Canadian hemlock problem "Need Help"

vmachnig

I am having a persistent problem which I can use some help with. I have 50 canadian hemlock trees and most of then are doing fine however every year around this time one or two will drop all or most of their needles and eventually die. There is no apparent reason I can find, no signs of pest infestation, the trees on either side are healthy and it is really confounding me at this point as to what might be causing it. I can see no signs that they are in trouble before handle.
I have one right now, it is about ten ft tall and has three separate trunks. one of the trunks has dropped all of its needles in a matter of days but the branches are flexible and still appear to be alive. the other two trunks are fine and show no signs of a problem.

In the past when I have caught one at it's early stages of dropping it's needles I have been able to save a couple by doing every thing I can think of, spraying with insectiside fertilizing and continual watering but I don't know if one or any of the things I have done provides the solution or not. Initially when this first started I tried one thing at a time but I lost those trees when I did so and that is why I have done everything at once.

All of the trees were planted about 5 years ago when they were about 5 ft tall and they are all about 8 to 10 ft now. They are planted along my property lines on three sides and not near the street so as to not be effected by the salt. the proplem is completely random and has happened in different locations and the trees to each side of the ones effected are healthy. It also is not necessarily the entire tree if it has mulpiple trunks.

Any suggestions would be greatly appreciated.

vmachnig

I'm adding some Pictures of the problem

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treevet

My initial guess would be water stress. Too much and or too little. Lots of nurseries do not sell them around here because of climate changes that make them very difficult to establish. I have lost many myself. It takes much monitoring to be successful. Too much heat and no water (do you water) will kill them more than other plants and by the looks of the neglected bed (weeds) my guess is they fend for themselves until an emergency is noticed.

Also that looks like a low area where spring rains may lay and suffocate roots.

Only the strong will survive in some circumstances.

Hemlocks can be found in creek beds at 100' plus. That tells something.

TreeCo

Could it be hemlock wooly adelgid?

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treevet

I would have thought that but he said the above. Hemlocks are a pain in the ass to get established.

Dave-o

I'm wondering if its not root bound. (Is that what its called?) When the root of the tree actually grow around the base of the tree... As the tree and root get bigger, the root eventually chokes off the tree and it dies. This happens, in my experience, to Hemlocks with multiple trucks.

If you had an infestation problem, you would have seen signs long before needles started dropping.

Too much water ISN'T the problem. Hemlocks grow perfectly fine next to riverbeds and streams.

Yardsmith

I'm just joining and don't know if you solved this problem - the problem described in the one reply is called "girdling" as in the roots are in a "girdle" created by their own roots system. This could occur because the plant is root-bound in a pot and then planted without tending to the roots that are wrapped around the outside of the plant. The roots will continue to grow in that manner and eventually damage/kill the plant.

Another way that girdling occurs is the hole that was originally dug for the plant was filled with amended soil that is dissimilar from the existing soil. If the amended/new soil is soft and fluffy and full of nutrients the root system stays in the amended soil and doesn't try to grow roots into the existing soil. Eventually the "hole" becomes filled with roots, many of which will girdle the plant and may kill it.

The other advice I would give you is get someone from the county extension service to visit or take them pictures and samples. I am a landscaper and use our county extension services to help ID plant problems all the time.

birchwood

I would take a soil sample to a county extension agent for starters. I have the same sort of problem with my hemlocks due to heavy soil. The other thing I noticed from the pictures is the exposed location. Hemlocks like sun, but dislike windy,dry exposed sites, and judging from the pictures it sort of looks open and exposed. Hope this helps.

sirpouralot

Root bound would normally show systems more gradually and would not be my first thought on this one, since the same result has been seen multiple times, and in each case it was very sudden. One would still have to rule that possibility out though if nothing else is apparent.

In this case it also seems unlikely that it is environmental i.e.. (sun, wind, exposure water, soil) or even an insect problem since it only effects part of the plant in a row of the same species.
2 things to look for here. Take a look first near the base of the stem that is dying back to make sure you don't have any girdling due to rodent chewing. Next Check for the presence of moles tunneling underneath the root systems.
Roots left exposed to cold air will freeze in late winter and will cause portions of the tree to die very quickly while the rest of the tree remains green and healthy. If you still don't see a cause, then try uncovering the roots to see what they look like. If you don't know what a healty root system should look like, compare it with the roots you see on one that looks healthy. Or post some pictures of the roots. Please post back and let us know what you find. Arborist in Michigan

windthrown

Tsuga canadensis, commonly known as Eastern or Canadian Hemlock. We call them Eastern Hemlocks down here. No needle cast diseases that I know of attack eastern hemlocks. Out here western hemlocks have only one common needle cast disease, and that is Rhizoshpaera needle cast (a fungus). There is an insect that targets easter hemlocks called the hemlock woolly adelgid (Adelges tsugae), a sap-sucking invasive bug accidentally introduced here from Asia.

Your trees do not look like thay have either of those problems though. They look more like random drought die-off to me. I have to counter what some others have said here, as Hemlocks actually evolved to grow in the shade, and not in full sun. They are not sun loving trees. For that reason they have a curled leader designed to poke through the canopy and grow as a secondary species in established forests. I would look for sun scald on the lower trunks myself. The cambium may be burned on some of the lower trunk. You could use white-wash to help prevent that if that is the problem. Or as others have said, there may be rodent damage to the lower tree and roots, though I have never seen gopher, vole or mole damage to hemlocks here. We have western and mountain hemlocks here in the wild west, and a few eastern hemlock cultivars planted in yards.