Hemlock stumps do not resprout, so a stump ground below grade is finished, and most hemlock stumps in western North Carolina now come from trees killed by the hemlock woolly adelgid. The work is usually about access and ground, because hemlocks grow on cool, moist slopes, ravines and stream banks.
Why so many hemlocks are dead
The NC Forest Service says hemlock woolly adelgid was first recorded in North Carolina in 1995 and had reached nearly all the state's hemlock-growing counties by 2005. It attacks and kills both eastern and Carolina hemlock, the only two hemlocks native to the state, and infested trees usually die within a few consecutive years. Clemson Extension puts it at as little as two to four years. Clemson also points out that hemlock death affects property values and personal safety in residential areas. That is why so many mountain properties have a run of grey, needleless hemlocks, or a row of stumps where they stood.
Carolina hemlock and eastern hemlock
Eastern hemlock is the common one. NC State Extension describes Carolina hemlock as a tree of cliffs and ridges from the Blue Ridge to eastern Tennessee, often confused with eastern hemlock, and says the adelgid is making it rare in western North Carolina. The USDA plant guide for eastern hemlock says that in the south of its range it grows only where cool, moist air drains, on valleys, ravines, hillsides and lakeshores. Either way, a hemlock stump is rarely on flat, open lawn. It is down a bank, beside a creek, or at the bottom of a steep yard.
Shallow roots and toppled hemlocks
The USDA plant guide says hemlock's shallow root system makes it highly susceptible to windthrow. Dead hemlocks are worse, so many come down whole, leaving a root plate standing on edge with soil and rock in it. That cannot be ground flat; it is lifted out and the hole backfilled. A cut stump is easier. Like most conifers, hemlock does not resprout from the stump, so there is nothing to kill. The question is getting a machine beside it, and on steep ground that has its own page: steep slope stump grinding.
Hemlocks beside streams
Many hemlocks shade creeks, and that ground has rules. NC DEQ explains that land-disturbing activity next to designated trout waters must keep an undisturbed buffer twenty-five feet wide, measured from the top of the bank, administered by the state's Division of Land Resources. Removing a fallen tree there is allowed with minimal disturbance, and ground cover must be kept. Grinding a stump leaves its roots in the bank to hold soil while they rot, which is usually kinder to a bank than digging. Ask the DEQ regional office or your county erosion control office before any work near a stream; stumps on creek banks explains more.
Grinding a hemlock stump on a slope
The tracked grinder walks to the stump and takes it four to eight inches below the surrounding grade. On a slope, the grindings need more thought than on a lawn. A storm can wash loose chips down a bank and into a creek, so on banks they are usually packed back into the hole and topped, or hauled. A dead hemlock that stood for some years before it was cut may be soft near the outside. That does not change the method, only the speed.
Saving the hemlocks you still have
If some hemlocks are still green, they may be worth treating. The Henderson County NC State Extension center describes soil-applied systemic insecticides that the tree takes up into its sap, says treatments last about five years, and notes that trees not more than half defoliated have a good chance to recover. It stresses reading and following the label. The NC Forest Service says systemic treatment is mainly for high-value trees and suggests talking to an arborist in your area. Tree still standing and you are not sure which way to go? Send a photo and we will talk through what comes after.
Hemlock stumps in the woods
Not every hemlock stump needs to go. The USDA plant guide notes that hemlock seedlings often depend on decaying wood: outside the ideal conditions, new hemlocks get started mainly on rotten logs, stumps and mounds, which hold moisture and warmth. A stump deep in the woods does no harm and does some good. Grind the ones in the yard, the drive, the path and the mowing line, and let the woodland ones rot where they are.
Common Questions
Do hemlock stumps sprout after the tree is cut?
No. Hemlock is a conifer and, like most conifers, does not come back from a cut stump. There is nothing to kill or treat. Grinding a hemlock stump below grade is a finished job, and stumps out of the way in the woods can simply be left to rot.
Can a hemlock stump be ground next to a trout stream?
Often it can, but check first. NC DEQ requires a twenty-five foot undisturbed buffer along designated trout waters for land-disturbing activity, with ground cover kept. Grinding leaves the roots holding the bank, which disturbs far less than digging. Ask the DEQ regional office or the county erosion control office before work starts.
How fast does hemlock woolly adelgid kill a hemlock?
Within a few years. The NC Forest Service says infested hemlocks usually die within a few consecutive years, and Clemson Extension says it can take as little as two to four. Trees that have lost no more than about half their needles have a good chance of recovering with treatment, according to NC State Extension.
What to Do Next
Send a photo of each hemlock stump with something for scale, one of the slope or route in, and your town, and say whether a creek is close by. Call (828) 574-4474.