Needle dropping and cedar flagging is a natural process that is often confused with a disease. Evergreen plants, including conifers (cedars, firs, hemlocks, redwoods, etc) and broad leaf types (laurels, rhododendrons, etc) naturally shed some old foliage each year. Although the loss of your evergreen’s needles may at first be disconcerting, the period of natural leaf fall for the species must be taken into consideration. However, if the trees are shedding the current season’s needles, or if the current season’s needles are turning brown, it may be time to consult an arborist.
As a result of both natural and environmental stresses, evergreens shed their older needles. As do other plants, evergreens shed their older needles after a number of years. In conditions of natural leaf drop, the needles usually last around three years. Juniper and Douglas fir needles last for 10 or more years, while Bristlecone pine needles can persist up to 30 years.
Symptoms of needle drop and cedar flagging include the development of brown foliage on the tree or shrub in late summer and persist into mid-late fall. Affected foliage is growth from previous years while foliage developed during the current year (new growth at branch tips) remains green. The brown branchlets, called flags, are generally spread uniformly through the canopy. Most of the dead foliage is blown or washed out of the plant by wind and rain in fall and winter and the tree typically looks green and healthy again by spring.
– Additional irrigation may be needed during periods of summer drought.
– Alleviate root disturbance from construction damage or other factors.
– Correct poor planting practices when feasible. If affected plants were planted too deeply, it may be possible to replant them during the dormant season if they are not too large.
– Doing nothing and let nature do it’s thing