Grifola frondosa

Common name: Hen of the Woods, Sheepshead, Maitake (Japanese).

Description: Grifola frondosa, a polypore, is a large cluster of grayish-brown fan or spoon shaped caps or fronds attached to a multi-branched, central stem. The stems of individual fronds are laterally attached. This mushroom grows in a rosette pattern, almost always at or near the base of an oak tree, but occasionally with other species of trees.

Fruiting bodies typically range from 4 to 24 inches (10 to 60 cm.) wide and 3 to 16 inches (7.5 to 40 cm) tall. Typical specimens range in weight from 3 to 30 lbs (1 1/3 to 4.5 kg), but specimens weighing over 100 pounds (45.5 kg.) have occurred. The individual caps range from ¾ to 3 inches (2 to 7.5 cm.) wide, and 2 to 10 inches (5 to 25 cm.) long (including the lateral stalk). The short to rudimentary, white, central stalk is ¾ to 3 inches (2 to 7.5 cm.) wide, and 1 to 4 inches (2.5 to 10 cm.) tall, and splits into many branches.

The pores are white and decurrent (running down the stalk). The pores are quite small and round when young, becoming angular and larger with age. The spore print is white.

Grifola frondosa has been studied for its’ medicinal properties. It has been demonstrated to be effective in stimulating the immune system, and hence can aid a body in its fight against various cancers. Research has also shown that this mushroom has a hypoglycemic effect, and may be beneficial for the management of diabetes. 

Ecology/associated hosts: Grifola frondosa is a weak parasite on the roots of trees, primarily oak, thereby causing a white butt rot. It will fruit at the base of an oak tree for many years when conditions are proper, sometimes singly and sometimes in clusters. Mushroom hunters often record the location of trees where hens of the woods have fruited, as they often will fruit in the same location in subsequent years. Hens of the woods will often continue to function as a saprobe after the tree they were parasitizing has died, so the location can produce for several years after the death of the tree.

Occasionally hens are found growing with other species of trees than oaks but this is not a common event.

In the Midwest, hens fruit from late August through October.

Like the smaller similar summer mushroom, Polyporus umbellatus, hen of the woods grow from an underground tuber-like sclerotium about the size of a potato.

Poisonous/harmful look-alikes: There are no poisonous look-alikes of this mushroom. The closest look-alike is Meripilus giganteus (a.k.a. Meripilus sumstine)i, the black-staining polypore, which also grows in a rosette pattern at the base of oaks, primarily with fan to spoon shaped caps or fronds. The fronds of Meripilus giganteus, which is also edible, are much thicker than the fronds of Grifola frondosa. Typically hen of the woods caps are 1/8 to ¼ inches (3 to 6 mm.) thick and Meripilus giganteus fronds range from ½ to ¾ inches (12 to 19 mm.) thick. The caps of Meripilus giganteus usually stain black with handling, while hen of the woods caps do not stain. This characteristic can be used to distinguish the two species.

Meripilus giganteus M. giganteus with stain

Harvest: Hen of the woods is a very large mushroom, with a very thick stem, so a large knife is necessary for harvesting. A folding filet knife, with a five inch blade, is adequate. The long blade is useful for cutting the stem of the mushroom, and for trimming off the lower fronds. The lowest fronds are usually covered in dirt and should be discarded because they are almost impossible to clean. One method of harvesting is to break the mushroom from the ground, and then cut off the lower, dirtier portions (both stems and caps). This mushroom generally requires extensive cleaning. The point where the cap becomes stem almost always has some grit picked up when the mushroom emerged from underground. These must be thoroughly cleaned.

Hen of the woods mushrooms should be harvested when young and tender. Once the pores have widened and become angular, the mushrooms are usually beyond their prime for harvesting. Only fresh, young specimens, with nearly closed pores, should be picked.

Possible allergic reactions: Hen of the woods is a choice edible. Its mushroomy flavor is both wild and woodsy. While this mushroom is excellent merely sautéed in butter or olive oil with garlic and salt as a side dish, hens can be used in many dishes: pastas, stir fries, risottos, Cajun dishes, Thai cuisine, etc.

Grifola frondosa is a fairly safe mushroom for most people, but just like most other foods, some people may have allergic reactions to them. Michael Kuo (see references below) is one author who has acknowledged having mild gastrointestinal distress from eating this mushroom.

Storage: This is one mushroom that can be frozen directly without preliminary sautéing. Hens also can be dried (only in certified kitchens), and stored in air tight containers almost indefinitely.

When fresh, store hen of the woods in paper bags or wax paper, but not in plastic bags or closed containers.


G. frondosa on end of a log A small G. frondosa
A group of G. frondosa, young and old Young G. frondosa surface
G. frondosa with pores A 36 pound G. frondosa


Kuo, Michael and Methven Andrew S. (2014) Mushrooms of the Midwest, University of Illinois Press, pp 185-86.

Binion, Denise E., Stephenson, Steven L., Roody, William C., Burdsall Jr., Horold H., Vasilyeva, Larissa N., and Miller Jr., and Orson K. (2008), Macrofungi associated with oaks of Eastern North America, West Virginia University Press, p. 281.

Roberts, Peter and Evans, Shelley (2011) The book of Fungi, University of Chicago Press, p. 389

Lincoff, Gary H. (1981) National Audubon Society Field Guide to North American Mushrooms, Alfred A. Knopf , pp. 463-64, plates 474, 475.

Arora, David (1979, 1986) Mushrooms Demystified, Ten Speed Press, pp. 564-65.

Kuo, Michael (March 2010) Grifola frondosa: the Hen of the Woods

Michigan Mushroom Hunters Club, September 2009 Mushroom of the Month