The plant is found from Alaska east to British Columbia, Ontario and Michigan; and south to California, Baja California, and New Mexico, and further south into Northwestern Mexico. It grows from sea level in the north, up to elevations of 2,500 m (8,200 ft) in its southern range.
Rubus parviflorus is a dense shrub up to 2.5 meters (8.2 ft) tall with canes no more than 1.5 centimeters (0.59 in) in diameter, often growing in large clumps which spread through the plant's underground rhizome. Unlike most other members of the genus, it has no prickles. The leaves are palmate, up to 20 centimeters (7.9 in) across, with five lobes; they are soft and fuzzy in texture.
The flowers are 2 to 6 centimeters (0.79 to 2.36 in) in diameter, with five white petals and numerous pale yellow stamens. The flower of this species is among the largest of any Rubus species, making its Latin species name parviflorus ("small-flowered") a misnomer.
The plant produces edible composite fruit approximately a centimeter in diameter, which ripen to a bright red in mid to late summer. Like other raspberries it is not a true berry, but instead an aggregate fruit of numerous drupelets around a central core. The drupelets may be carefully removed separately from the core when picked, leaving a hollow fruit which bears a resemblance to a thimble, perhaps giving the plant its name.
Thimbleberry fruits are larger, flatter, and softer than raspberries, and have many small seeds. Because the fruit is so soft, it does not pack or ship well, so thimbleberries are rarely cultivated commercially.
However, wild thimbleberries can be made into a jam which is sold as a local delicacy in some parts of their range, notably in the Keweenaw Peninsula of Upper Michigan. Thimbleberry jam is made by combining equal volumes of berries and sugar and boiling the mixture for two minutes before packing it into jars. The fruits can be eaten raw or dried.
Rubus parviflorus is cultivated by specialty plant nurseries as an ornamental plant, used in traditional, native plant, and wildlife gardens, in natural landscaping design, and in habitat restoration projects. The fruit has fragrance. Thimbleberry plants can be propagated most successfully by planting dormant rhizome segments, as well as from seeds or stem cuttings.
The flowers support pollinators, including of special value to Native bees, honeybees, and bumblebees. The fruit is attractive to birds. It is the larval host and a nectar source for the yellow-banded sphinx butterfly.
A double-flowered form of the thimbleberry was discovered near Squamish, BC, by Iva Angerman (1903–2008) of West Vancouver, BC. This clone does not appear to be in commerce, but is grown in the Botanic Garden of the University of British Columbia, Vancouver, and in the Native Plant Garden of the Royal British Columbia Museum, Victoria.
Another double-flowered thimbleberry was found about 1975 by Bob Hornback on Starrett Hill, Monte Rio, California and given the cultivar name 'Dr. Stasek', after an art instructor at Sonoma State University.
- Germplasm Resources Information Network: Rubus parviflorus, retrieved 17 May 2015
- Plants of British Columbia: Rubus parviflorus
- USDA: Native distribution map . accessed 2.12.2013
- U.S. Department of Agriculture. 2009. USDA: Rubus parviflorus
- C. Michael Hogan. 2008. Coastal Woodfern (Dryopteris arguta), GlobalTwitcher, ed. N. Stromberg
- Lady Bird Johnson Wildflower Center — Rubus parviflorus . accessed 2.12.2013
- Las Pilitas Nursery horticultural treatment: Rubus parviflorus — Thimbleberry . accessed 2.12.2013
- US Forest Service Fire Ecology
- Griffiths, Anthony J. F. and Ganders, Fred R. (1983). Wildflower Genetics-a Field Guide for British Columbia and the Pacific Northwest. Flight Press, Vancouver. ISBN 0-919843-00-X.
- Native American Ethnobotany (University of Michigan - Dearborn) — for Rubus parviflorus . accessed 2.12.2103
- Chesnut, Victor King (1902). Plants used by the Indians of Mendocino County, California. Government Printing Office. p. 408. Retrieved 24 August 2012.
|Wikimedia Commons has media related to Rubus parviflorus.|