Issue 16, October 6, 2014
Seasonal Needle Drop
Around this time of year, the U of I Plant Clinic receives many calls regarding yellowing needles on evergreens. The appearance can be quite alarming to homeowners whose seemingly healthy evergreens suddenly turn yellow and drop large numbers of needles. Fortunately, most are witnessing a harmless and natural part of the plant's cycle. Despite the name, evergreen foliage does not stay on the plant forever. Evergreens commonly shed their less productive or older needles. Most pine species shed their needles after 3 to 4 years. The occurrence is more noticeable on some species, such as white pine, and less evident on others, such as spruce and fir.
Seasonal needle drop is usually confined to the innermost (oldest) needles. Homeowners should be more concerned when the new/current season's growth suddenly discolors, wilts, or drops from the plant. Damage occurring to the new growth could be the signal of a more serious pest or cultural problem. (Travis Cleveland)