Rubus parviflorus (Thimbleberry)
|Also known as:|
|Life cycle:||perennial woody|
|Habitat:||part shade, sun; open woods, woodland edges, forest clearings, thickets, stream banks|
|Bloom season:||June - July|
|Plant height:||3 to 6 feet|
|Wetland Indicator Status:||GP: FACU MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Clusters of 2 to 9 stalked flowers at stem tips of second year canes. Flowers are white, 1¼ to 2 inches across with 5 broad, rounded petals that often have the texture of crumpled tissue paper. In the center is a cluster of many styles surrounded by a ring of numerous yellow-tipped stamens that turn brown with age.
Flower stalks are 1/3 to 1½ inches long, densely covered in a mix of short glandular and non-glandular hairs. The 5 sepals are broadly egg-shaped to triangular with an abrupt taper to a long, slender, tail-like tip, glandular on the back and short woolly-hairy on the inner surface, half or less as long as the petals (excluding the tail), and often reddish.
Leaves and stems:
Leaves are simple and alternate, roughly round or kidney shaped in outline, 4 to 11 inches long and about as wide, with (usually) 5 pointed lobes, palmate veins, and the base heart-shaped to deeply cleft. Edges are finely double-toothed, upper surface medium to dark green and sparsely hairy, lower surface paler green, hairy to sparsely hairy and glandular along the veins. Leaf stalks are 2½ to 7 inches long and covered in gland-tipped hairs. At the base of the leaf stalk is a pair of lance-shaped appendages (stipules) ¼ to ¾ inch long. Stems are mostly erect, mostly unbranched, glandular hairy the first year, becoming smooth with shedding gray-brown bark the second, dying out the third year. Stems have no bristles or prickles, do not root at the tip, and can form dense colonies from spreading rhizomes.
Fruit is a hemispheric cluster, ½ to ¾ inch in diameter, with many fleshy druplets, maturing from pale pink to salmon colored to bright red, easily separating from the receptacle, mushy and somewhat bland tasting.
Thimbleberry is a common species of higher alpine regions of the Rockies and the western coastal range, but in the Upper Midwest it is only present in close association with the Great Lakes. It is nearly continuous along the Lake Superior shoreline from Duluth north but diminishes quickly as one heads inland. Without its highly conspicuous flowers or fruit, the leaves might be confused with maples, especially the shrubby Mountain Maple, (Acer spicatum) that is also prevalent in the same habitat. But the leaves of all Acer species are opposite, where the leaves of all Rubus species are alternate. The fruit may look tempting and indeed one shouldn't be afraid to try it, though when ripe, even the slightest knock can cause them to fall from their receptacle, and after a brief sweet/sour taste, the mushy berry turns bland in the mouth.
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- Thimbleberry plant
- Thimbleberry plants
- fruiting plant
- a small colony of Thimbleberry in fall
- first-year, non-flowering cane
- a rain-soaked flower
Photos by K. Chayka taken in Cook and Lake counties. Photos courtesy Peter M. Dziuk taken in Cook, Lake and St. Louis counties. Other photos by nwplants.com are licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
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