Rosaceae

California blackberry

Rubus ursinus

California blackberry

Photo: USFWS - Pacific Region — Public domain · source

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Survives zone 7 through 9

Harvest calendar

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Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

The wild trailing blackberry of the U.S. West Coast, and a plant with an outsized role in berry-breeding history — crossed with a red raspberry, it produced the loganberry in 1880s Santa Cruz, and its genes run on through the boysenberry, youngberry and marionberry. Wild fruit quality is inconsistent — some clones are large and well-flavored, others large but sour or insipid — so seedling plants are something of a gamble compared with named cultivars bred from it.

Hardiness
Zone 7–9
Habit
Shrub
Edible part
Fruit
Ripens
Summer–autumn
Mature size
Trailing bramble, canes 2–6 m
Light
Full sun to partial (forest edge)
Soil pH
6.0–7.0 (near-neutral)
Environment
Temperate
Native range
Native to the Pacific coast of North America, from British Columbia south through Washington, Oregon and California to Baja California, and east to Idaho, in canyons, waste places, fields and forest edges below about 1000 m.
Status
Wild
Years to fruit
2–4 yrs
Growth speed
Vigorous trailing growth — canes can extend 5–6 m (15–20 ft) in a season, rooting at the tips as they go.
Spacing
150 cm (59 in) apart — about 2.3 m² (24 sq ft) per plant
Leaf shape
Compound, usually three-lobed or trifoliate leaflets on densely prickled, trailing-to-climbing canes reaching 5–6 m — a ground-hugging, mound-building habit rather than an upright cane.
Root system
Trailing stems root readily at the nodes and tips, and the plant also produces basal sprouts and root suckers, particularly vigorous after fire or cutting back.
Fruit description
A blackberry-type aggregate fruit, sweet when well-grown but variable in the wild — some plants produce large, sweet, well-flavored berries, others large but sour or insipid fruit; hollow-cored like other brambles once picked.
Propagation
By tip-layering in July — its natural means of spread — plus division of rooted tips in early spring or stratified seed sown in early autumn.
Pollination
Self-fertile

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.

Growing guide

Fertilizing. Grows well in ordinary well-drained loamy soil without heavy feeding; a spring mulch of compost is sufficient in cultivation, while rich, wet soils increase susceptibility to honey fungus and other rots.

How it spreads. A true trailing blackberry (dewberry-type) — long stems trail along the ground and root at the nodes and tips rather than standing upright like a raspberry or erect blackberry — and it also produces basal sprouts and root suckers, especially after fire or disturbance.

Growing tips. Bears on typical biennial canes — primocanes (first-year, leaves only) followed by floricanes (second-year, flowering and fruiting) — with densely prickled trailing stems. Thrives across a wide range of conditions from open sun to fairly dense woodland shade, though the best fruit comes from more open sites. Historically significant in berry breeding: R. ursinus is the documented parent species — crossed with a Rubus idaeus raspberry — behind the loganberry, bred (reportedly by accident) by James Harvey Logan in Santa Cruz, California in the 1880s, and it stands as a second-generation parent behind the boysenberry, youngberry and marionberry as well.

Grow journal

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About the data

Zone figures are typical published ranges — microclimate, drainage and siting shift them by a zone in either direction. Store links are found by an automated search, refreshed every six weeks. Availability is seasonal; stock and prices are not tracked.

Venlo — a reference for cold-hardy edible plants