Name: |
- Rubus, from the Latin, "bramble, briar"
- parviflorus, from the Latin parvus, "small, little,
insignificant," and florus, "bloom or flower"; hence, "small
flowered".
- Thimbleberry, from the shape of the fruit.
- Other common names include Western Thimbleberry, Salmonberry, Mountain
Sorrel, White Flowering Raspberry, Western Thimble Raspberry
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Taxonomy: |
- Kingdom Plantae, the Plants
- Division Magnoliophyta, the Angiosperms (flowering plants)
- Class Magnoliopsida, the Dicotyledons
- Subclass Rosidae, the Roses
- Order Rosales, the Roses
- Family Rosaceae, the Roses; with Amelanchier
(Juneberries), Aronia (Chokeberries), Crataegus
(Hawthorns), Malus (Apples), Physocarpus
(Ninebark), Potentilla (Cinquefoils), Prunus
(Cherries & Plums), Rosa (Roses), Sorbus
(Mountain Ash), and Spiraea (Spirea)
- Genus Rubus, the Brambles, with Dewberries,
Raspberries, and Thimbleberry.
- Taxonomic Serial Number: 25007
- Hybrids between Thimbleberry and Red Raspberry (Rubus idaeus)
have been reported. However, these hybrids are frequently sterile.
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Description: |
- A low, scrambling or erect, unarmed deciduous shrub 1½'-8'
tall.
- Leaves large, simple, palmately-lobed; green above
but pale beneath. Unequally serrate, turning brilliant orange to maroon
in fall.
- Stems perennial, few, erect, and simple. The stems,
or canes, typically live for 2 to 3 years. Sterile first-year stems
or primocanes, develop from buds at or below the ground surface and
generally bear only leaves. During the second year, lateral branches,
or floricanes, develop in the axils of the primocanes producing flowers
and fruit. Growth is rapid under favorable growing conditions. Maximum
rates of height growth often occur during the second and third years
after establishment.
- Twigs greenish and finely hairy.
- Bark greyish, becoming flaky or shreddy with age.
- Flowers showy white or, rarely, pink; in clusters
of 2-7.
- Fruit a "thimblelike" aggregate of numerous hairy,
red or scarlet drupelets. These drupelets are nearly dry at maturity
and fall apart readily when picked.
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Identification: |
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Distribution: |
- Alaska to California and into northern Mexico; east to the Great Lakes
States.
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Habitat: |
- A variety of moist-to-dry and wooded-to-open sites. Commonly grows
on open, wooded hillsides, along streambanks and canyons, on borders,
and roadsides.
- Frequently occurs as scattered individuals, but in some areas in dense
contiguous patches.
- Moderately shade tolerant.
- Although persisting in closed stands, typically most abundant on disturbed
sites within the forest canopy, such as cutover or windthrown areas.
- Soil: Grows well on a variety of barren infertile
soil types. Tolerates a wide range of soil temperature and pH but requires
adequate soil moisture for good growth. Grows well on dry, rocky soil
and deep well-drained loam. Growth best on loam or clay-loam, fair on
sandy loams, but poor on gravel, sand, or clay. Grows well on soils
derived from a variety of parent materials.
- Persistent successional species which frequently dominates the understory
during the first several decades after disturbance. It readily invades
disturbed sites through rhizomes or seedling establishment. Generally
occurs in greatest abundance in successional stands throughout its range
but can persist in trace amounts in many climax forests. In many mature
forest stands, thimbleberry may be restricted to disturbed sites such
as clearings or areas of windthrow. Plant vigor and canopy cover generally
decline as tree cover increases.
- A nitrogen-demanding species and in some areas, begins to decline
within 2-5 years after timber harvesting as soil nutrient levels decrease.
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Fire: |
- Resistant to and generally enhanced by fire. In areas of rigorous
fire suppression, fruit production and plant vigor have declined.
- Well adapted to vigorously invade many types of burned sites through
rhizomes or seed. Rhizome sprouting is an important postfire strategy
which enables rapid reestablishment and spread.
- A seed banker, also reestablishes through viable seed stored in the
soil or duff. Seed banking is an important postfire regenerative strategy
in Thimbleberry, a prolific seed producer. Thimbleberry seed is stimulated
by fire and subsequently germinates in great numbers. Most seedling
establishment occurs immediately after fire. Birds and mammals add to
seedling establishment by transporting seed to the site. The capacity
to regenerate through seed may be reduced by extremely hot, duff-reducing
burns.
- Although often top-killed, underground rhizomes generally survive.
High severity fires which damage belowground regenerative structures
may be most damaging to rhizomes. The aerial portions of relatively
few plants actually survive fire, except for those on unusual microsites.
Most seed stored on-site is probably unharmed by fire. Cover and vigor
are generally enhanced by fire.
- Capable of rapid, vigorous postfire spread through an extensive network
of often deeply-buried rhizomes. Sprouting through surviving rootcrowns
is also possible, although rhizome sprouting probably represents the
primary mode of postfire regeneration. Multiple sprouts often replace
the single stems observed in preburn communities.
- Sprouting of rhizomes is favored by fires of low intensity and severity.
Hot fires presumably offer greater potential for damaging underground
regenerative structures.
- Both sprouting and seedling establishment occur soon after fire. Growth
is rapid and some plants occasionally bear fruit during the first postfire
year. Thimbleberry generally reaches greatest abundance during the first
years after fire and decreases as the overstory canopy closes. Dwindling
soil nutrients may also contribute to its decline. Rhizome sprouting
may produce dense cover up to 3' tall within 3 years after disturbance
on some particularly moist sites. Dense early growth of aggressive species
such as Fireweed (Chamerion
angustifolium) can slow Thimbleberry establishment and growth.
- Factors other than fire severity and intensity can also contribute
to the rate of postfire recovery. Differences in the season of burn,
plant density and vigor in the preburn community, site differences,
and climatic factors all contribute to postfire recovery.
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Associates: |
- Trees: Quaking Aspen (Populus
tremuloides)
- Shrubs: Twinflower (Linnaea
borealis), Gooseberry (Ribes
oxyacanthoides), willow (Salix spp.), Red Elderberry
(Sambucus racemosa ssp. pubens),
- Herbs: Wild Sarsaparilla (Aralia
nudicaulis), Fireweed (Chamerion
angustifolium), Fleabane (Erigeron eximus), Cow Parsnip
(Heracleum
lanatum), Lupine (Lupinus spp.), Bracken Fern (Pteridium
aquilinum),
- Ground Covers:
- Mammals: Fruit is eaten by black bears and numerous
smaller mammals, including coyote, chipmunk, raccoon, red fox, gray
fox, red squirrel, and skunks. Provides cover for rabbits, red squirrel,
black bear, and beaver.
- Birds: Dense thickets form good nesting habitat for
many small birds. Fruits are eaten by many birds, including the ruffed
grouse, blue grouse, sharp-tailed grouse, American robin, thrushes,
thrashers, towhees, gray catbird, northern cardinal, pine grosbeak,
and brown thrasher.
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History: |
- Traditionally used by indigenous peoples throughout its range. The
fruit was eaten fresh in summer and dried for winter use. The bark was
boiled and made into soap, and leaves were used to make a medicinal
tea. Leaves were powdered and applied to burns to minimize scarring.
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Uses: |
- Fruits edible, although palatability tends to be greater towards the
eastern end of its range where rainfall is greater. Makes excellent
jelly but too seedy for jam.
- Young shoots may be eaten as greens; leaves have been used in making
teas.
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Reproduction: |
- Reproduces through seed but also regenerates vegetatively, even in
the absence of disturbance. Capable of forming dense thickets through
vegetative sprouting. Establishment from seed appears to be the primary
mode of colonization in newly disturbed areas. Abundant seedling establishment
typically occurs during the first year after disturbance.
- Seed: Fruits, or "berries," are made up of an aggregate
of numerous small red drupelets which fall to the ground when ripe.
Seed averages ¾" in length.
- Germination: Seeds have a hard, impermeable endocarp
and dormant embryo. Consequently, germination is often slow. Allelopathic
compounds produced by Bracken Fern (Pteridium
aquilinum) can apparently inhibit germination and subsequent
growth.
- Seedbanking: Seed noted for its ability to remain
viable for long periods of time. Seedbanking is believed to be an important
postdisturbance regenerative strategy.
- Seed dispersal by birds and mammals. Groups of seedlings
occasionally germinate from rodent caches. However, small mammals generally
play only a local role in seed dispersal. Birds often effect wider dispersal.
Gravity may also aid in seed dispersal.
- Vegetative regeneration: Strongly rhizomatous, also
capable of vigorous sprouting from rootcrowns and roots. A single seedling
can spread and occupy a relatively large area as rhizomes develop and
spread. Most local expansion of this shrub is attributable to rhizome
sprouting.
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Propagation: |
- Initial propagation is reportedly more difficult than for other Rubus
species.
- Seed may be difficult to obtain commercially. Specific germination
requirements have not yet been documented, but both warm and cold stratification
are probably required. Most Rubus seeds require, as a minimum,
warm stratification at 68 º to 86 º F for 90 days, followed
by cold stratification at 36º to 41º F for an additional 90
days. These conditions are frequently encountered naturally as seeds
mature in summer and remain in the soil through the cold winter months.
- Laboratory tests indicate that exposure to sulfuric acid solutions
or sodium hyperchlorite prior to cold stratification can enhance germination.
- May be propagated vegetatively by planting stem cuttings or rhizome
fragments. Best results have been obtained from starting dormant rhizome
segments. Several cultivars are now commercially available.
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Cultivation: |
- Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
- Occasionally planted as an ornamental because of its attractive fragrant
flowers and colorful fall foliage. Several cultivars have been developed,
including `Golden' and `Colonel'.
- It has the ability to form clumps which expand greatly once established.
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Links: |
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Comments: |
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Last updated on
8 March, 2006
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