Hemlocks make an excellent addition to your landscape.  In most cases, hemlocks are located along the perimeter of a property and make for a great privacy hedge.   Hemlocks in the Northeast are susceptible to the insect, woolly adelgid aphid, which came up from North Carolina during Hurricane Gloria in 1986.  The woolly adelgid aphid is easily spread from hemlock to hemlock in the wind.  Therefore, three spray applications are recommended every year (spring, summer and fall) to combat the woolly adelgid aphid infestation.