You can use the search tool on the ISA (the accrediting organization) website to find a certified arborist. Another option is to search for a Maryland licensed tree expert; they should receive essentially the same training and exam to pass. Arborists cannot cure every ailment (treatments are not always possible or curative), but should be able to help diagnose an issue as well as look for sources of tree stress that make it more vulnerable to pest or disease issues.

Hemlock are vulnerable to three primary pests, especially when stressed by drought or high summer heat: Hemlock Woolly Adelgid, one or more species of scale insect (like Elongate Hemlock Scale), and rust mites. Of the three, the adelgid is probably the most serious or damaging, and a heavy infestation can kill a tree in a few years. (Sadly, it has done so with many wild hemlocks in the eastern U.S.) Needle drop can be caused by a range of stressors, not always a pest, but this is something an arborist can look for.

Treatment often involve using a systemic pesticide, the ingredients of which may be illegal for the general public to purchase and apply (depending on what is used) since they could harm pollinators. (Although hemlock is not pollinated by insects, its windborne pollen might carry those residues onto other plants.) Many arborists do also carry a pesticide applicator certification from the MD Dept. of Agriculture, but if the person who assesses your tree does not, you may need to hire someone separately to make pesticide applications if they are deemed warranted. Since the threat of adelgid, scale, and mite outbreaks is ongoing, treatments might need to continue for the life of the tree, though how often they are applied will depend on the product used.

Miri