NDSU Extension - Mercer County


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Fall Needle Drop in Conifers

fall needle drop, conifers, evergreens

Submitted by Craig Askim, Extension Agent/Agriculture and Natural Resources

Fall Needle Drop in Conifers

During autumn, deciduous trees like green ash and linden change color and lose their leaves.  This is normal and expected.  It happens every year and people are used to it.  When needles of evergreen trees turn brown and die, it is definitely unexpected, but not necessarily abnormal. 

Several species of evergreens or conifers are frequently grown in North Dakota.  Pines and spruces are most common.  Pines have relatively long needles (two to nine inches), which are held in clusters called fascicles.  Scotch pine trees have two needles per fascicle, about two to four inches long, and they are usually twisted around each other.  Needles of ponderosa pine are in bundles of two or three (usually three) and are four to nine inches long.  These needles live for two to seven years, and then die and drop during the fall.  These are the older needles toward the center of the tree. 

Another common group of conifers are the spruces such as Colorado blue spruce and Black Hills spruce.  These trees have shorter needles, about three-quarter to an inch long, and are attached to the stem individually, not in bundles.  Blue spruce needles are more pointy, or sharper, than those of Black Hills spruce.  Spruce needles usually live longer than pine needles, and may persist for up to 10 years.  Just like pines, the needles that are older and more shaded will turn brown and drop during autumn. 

Some needle drop by conifers during the fall is normal.  The exception occurs with larch trees (also called tamarack).  Larch trees lose all of their needles every year because they are deciduous evergreens.  Larch needles are one to two inches long and borne in clusters on short shoots, or individually on long shoots.  The needles are also very soft.  Some larch trees are native to the swamps and bogs of northern Minnesota.  A common larch in North Dakota is the Siberian larch, which can tolerate the severe winters.  Larch needles turn bright yellow and provide a golden rain during autumn.

Evergreen needles do not last forever.  Some needle loss towards the center of the tree, during autumn is normal.  Needle loss at other times of the year is not normal and may be due to an insect or fungal pest or the result of severe environmental stress.  Larch trees, the exception to the rule, lose all of their needles every year. Trees and lawns get the most benefit from fertilization when applied during the fall. Enjoy the colors this fall.

Source:  Joseph Zeleznik, Ph.D., Extension Forester 701.231.8143, joseph.zeleznik@ndsu.edu

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