Fall Browning of Evergreen Foliage
FOR IMMEDIATE RELEASE
October 30, 2012
questions arise concerning the foliage on evergreens changing color
dramatically. Callers are convinced that
their plants must have some type of virus or fungus and want to know what can
be done. "There is really nothing
to be concerned about," explains Martha Smith, Horticulture Educator,
University of Illinois Extension.
"What is happening is commonly called inner needle drop or third
year needle drop."
All trees and
shrubs renew their foliage annually, producing new leaves in the spring of the
year and shedding old leaves in the fall.
The leaves of deciduous plants such as maples and oaks live for one
growing season and then fall off usually in a blaze of color. But evergreen foliage lives from one to several
years, depending on the species. As new growth emerges in the spring, last
years growth becomes shaded. Its role as
primary photosynthesizer is over. During
late September and October, this inner or older foliage dies and falls
In some species
like white pine and arborvitae, this fall browning takes place rather
suddenly. The older needles turn a
bright gold-yellow and remain attached for about 7 to 10 days depending on
weather. If we have strong autumn winds
and heavy rains, these needles fall quickly.
Sometimes, this natural occurrence is hardly noticed. But every few years it is very noticeable,
and people become concerned.
foliage drop may be distinguished from cases of severe foliage damage due to
disease by its uniform appearance over the whole tree and its common occurrence
on neighboring trees of the same kind.
It is also confined to the innermost or oldest needles. Nearly all pines bear needles in bundles of
two to five, and the needles remain together when they drop.
No harm is
done to the tree by the loss of this foliage.
The amount dropped depends somewhat on the condition of the tree and the
preceding growing seasons. Less vigorous
individuals will lose a greater proportion of their total leaf area. If the new, terminal, or current year's
growth is fresh and vigorous, the health of the tree is not in jeopardy.