thimbleberry

not listed

NNR - Unranked

SNR - Unranked

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Thimbleberry is an erect perennial shrub that rises from an underground horizontal stem (rhizome). It can be 40″ to 80″ long, though in Minnesota it is usually no more than 18″ to 48″ in height. It often forms large, dense clumps.

A series of biennial stems (canes) are sent up from the perennial rhizome. The canes are erect to ascending, and unbranched. They do not have bristles or prickles. In the first year they are green and are covered with glandular hairs. In the second year they are woody and hairless and the bark is thin, tan, papery, and flaky.

The leaves are large, alternate, deciduous, and long stalked. The leaf stalks are 2¼″ to 7″ long and are covered with reddish, gland-tipped hairs. At the base of each leaf stalk there is a pair of leaf-like appendages (stipules). The stipules are lance-shaped and ¼″ to ¾″ long. The leaf blades are velvety to the touch, round to kidney-shaped in outline and about as long as wide. They are usually 4″ to 8″ long, sometimes up to 12″ long. They and are heart-shaped or deeply cut at the base, and are palmately cut into usually 5, sometimes 3, shallow, pointed lobes. The lobes are cut no more than one third of the way to the midvein. The upper surface is green and sparsely to densely covered with short hairs. The lower surface is somewhat lighter green and similarly hairy but with glandular hairs along the main veins. The margins are irregularly toothed or double toothed with sharp, forward-pointing teeth.

The inflorescence is either a single flower or a long-stalked, leafy, flat-topped cluster (corymb) with 2 to 10 large flowers at the end of the stem. They appear from May to late July, peaking in late June to late July. Each flower is in a ⅜″ to 1½″ long stalk (pedicel). The pedicel is densely covered with glandular hairs.

The flowers are 1⅜″to 2″ in diameter. There are 5 sepals, 5 petals, and numerous stamens. The sepals are green, egg-shaped to triangular, and have a narrow, elongated, tail-like tip. They are ⅜″ to 11 ⁄16″long including the tip. They are covered on the back (outside) with very short, orangish-yellow, gland-tipped hairs; and on the inside with white non-glandular hairs. The petals are white, broadly egg-shaped to nearly circular, and ⅝″to 1″ long. They have a texture like crinkled tissue paper. The stamens are pale yellow.

The fruit is a juicy, fuzzy, broadly hemispheric, ⅝″ to ¾″ wide aggregate of multiple drupelets. It is initially pinkish-white, becoming progressively darker pink, eventually bright red when ripe. It matures in early August to mid-September. When ripe it falls intact to the ground.

40″ to 80″

White

Moist to moderate moisture. Forest clearings, woodland openings, thickets, roadsides, power lines. Partial sun.

May to late July

thimbleberry stem gall wasp (Diastrophus kincaidii)

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30.

Native

The primary range for this species is western North America, stretching from New Mexico to the Pacific coast and north to Alaska. The presence of isolated populations in the Great Lakes region is probably due to a once contiguous range separated by repeated glaciations.

Uncommon but often locally abundant

Plants from coastal California have been recognized as var. velutinus. The underside of the leaves tend to be densely hairy. However, this may be an environmentally induced variation. Most taxonomists do not recognize any varieties of thimbleberry.

Found on the Superior Hiking trail, about 3-4 ft. tall. In one area of the trail it seemed to be everywhere.

Habitat

Plant

Infructescence

Fruit

Leaves

Location: Cook County, Superior Hiking Trail

Found on the Superior Hiking trail, about 3-4 ft. tall. In one area of the trail it seemed to be everywhere.

Location: near the lower falls at Gooseberry Falls State Park.