wpe5.jpg (2127 bytes)U.P. TREE  IDENTIFICATION  KEY
from Michigan State University Extension

THE WILLOWS
Black Willow, Peachleaf Willow, Weeping Willow, Willow spp.
Salicaceae, The Willow Family

XWIL-flower-top.jpg (17880 bytes)The willow family has many tree and shrub species. World-wide there are about 335 species in two genera, Salix (willows) and Populus (aspens). The family is most abundant in cooler, temperate regions of the northern hemisphere with about 120 species in North America.  World-wide there are about 300 species of willow (Salix spp.) with about 70 in North America.  Only 38 of these reach tree size with only 3 in the U.P.  There are many U.P. shrub species.
   Willows tend to prefer moist, cool SITES. They are usually found along stream courses or in wetland complexes.  Willow FLOWERS that are most well-known would be the "pussy willow" (Salix discolor) but most willows have rather pretty flowers that bloom early in the spring (good for bees).  Most willows have long slender LEAVES.  Sometimes close attention to details will help identify species.  Willows do not have true
terminal BUDS and the side buds are usually pressed close to the twig.  Salix is a difficult genus to identify species.  Another interesting tidbit about willows is the origin of aspirin from willow bark.  The technical name for aspirin is "acetyl
salicylic acid".  The "salic" refers to "Salix", which is the latin name for willow. 


Willow Black.jpg (41166 bytes)  BLACK WILLOW   (Salix nigra)
 
Other Names:   Willow, Swamp Willow
  Key ID Features:  Leaves, Yellow Twigs, Size

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LEAVES of black willow are 3-6 inches long and only a half-inch wide.  Leaves have rounded bases.  The base of the leaf stalk often has a pair of small bumps called "stipules".  The margins are finely-toothed and the leaf tips quite tapered.  The TWIGS are usually bright yellow and can be easily noticed while driving along a highway.  The BARK becomes furrowed at a fairly young age, deeply furrowed with thick ridges with large trees.  Trees can reach DIAMETERS of over 3 feet but rarely grow taller than 50-60 feet.  Often there are multiple TRUNKS.  The wood is weak and large trees often have large broken branches from wind or ice storms.  The BRANCHES tend to be drooping which can confuse identification with weeping willow.  Black willow commonly grows singly or in small groups along roadsides and ditches.  Occasionally it becomes part of a forest stand with red maple, balm-of-Gilead, and other wetland hardwoods. Common pests: large aspen tortrix, leaf galls, mourning cloak, tussock moths, aphids.


Willow Peachleaf.jpg (41916 bytes)  PEACHLEAF WILLOW  (Salix amydaloides)
  Other Names:  None Known
  Key ID Features:  Leaves, Yellow Twigs

LEAVES are similar to black willow but with a slightly wider appearance, are somewhat leathery, and are whitish underneath.  Leaf bases form a sharp "V".  Generally the leaf stalks have only a very small pair of stipules (bump-like growths) or none at all.  The leaf margins are finely-toothed.  TWIGS are yellowish and somewhat droopy as with black willow.  Twigs are fairly flexible where black willow twigs snap easily.  The tree is SMALL, 10-35 feet high, with diameters reaching around a foot or so.  Common pests: large aspen tortrix, leaf galls, mourning cloak, tussock moths, aphids.


SOME OTHER WILLOWS 

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Weeping Willow  (Salix babylonica)
An ornamental tree imported from northern China.  More common further south of the U.P.

Pussy Willow  (Salix discolor)
Likely the most well-known willow.  Fairly easily identified in the spring with the characteristic "pussy willow" FLOWERS.  Reddish-brown TWIGS have long BUDS for a willow, about a centimeter long (0.4 of an inch).

Bebb's or Beaked Willow  (Salix bebbiana)
A TALL SHRUB, sometimes small tree, with very rough-looking, somewhat broken, gray BARK.   In winter, the willow looks almost dead due to its scrubby form and general appearance.  LEAVES are wide for a willow, widths about half the length, and woolly underneath. 
Coarse-toothed.  


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This site created and maintained by Bill Cook, MSU Extension Forester for the Upper Peninsula of Michigan.   Editing and modification is ongoing.  Submit suggestions, questions, and corrections to cookwi@msu.edu or call 906-786-1575. 

 

 

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