It’s that time of the year where we see a very noticeable needle drop on some evergreens such as arborvitae, pines and spruce. In fact, just this last past week I have received a number of calls on this very issue. Not to worry, as this is normal, and to be expected. Evergreens do not keep their needles indefinitely but will drop them after one to several years. This is a process that happens with these types of conifers, where 2- to 4-year-old needles, usually in the interior of the canopy by this time, turn yellow, then brown, and eventually drop off. For example, Ponderosa and Scotch pines usually keep their needles for three years. However, this pattern may vary from tree to tree and year to year. Also, this process may be a gradual one, or all the older needles may turn in a very short period of time.
If the needle dropping is sudden, and people are not familiar with this process, it is often that they become concerned about the health of these trees. Again, this natural phenomenon occurs every year, and does not by any means hurt the tree.
Having said that, be sure to check that only the older needles towards the center of the shrub or tree, are the ones browning and dropping. The needles on the ends and tips of the branches should look fine, having their normal green color.
Check to see that there is no spotting or banding on the needles on the ones that are turning yellow. If spotting or banding is noted, take a sample to your local county extension office for diagnosis.
What’s more, if the tips of the branches (candles) have turned brown, brittle, and are hollow inside, or if whole branches and sections of the plant have died back, again, be sure to contact your local extension office. They have information for the proper remedial actions to take.
Rip Winkel is the Horticulture agent with K-State Research and Extension – Cottonwood District. Contact him by email at firstname.lastname@example.org or call either 785-682-9430, or 620-793-1910.