boulder raspberry

Photo: Ulf Eliasson — CC BY 2.5 · source

Survives zone 5 through 8

Harvest calendar

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

Grown almost exclusively as an ornamental for its large white rose-like flowers rather than for its fruit — sources consistently describe the berries as dry, seedy and only sparingly fleshed. PFAF and other references note the flavour is pleasant but the fruit itself is 'rather on the dry side' with 'lots of seeds to very little flesh,' and wild forms are generally considered to have unappealing fruit — this is a flowering shrub first, an edible second.

Hardiness

Zone 5–8

Habit

Shrub

Edible part

Fruit

Ripens

Summer–autumn

Mature size

Arching thornless shrub 1.5–3 m

Light

Full sun to partial

Soil pH

6.0–7.0 (near-neutral)

Environment

Temperate

Native range

A narrow endemic of the south-central Rocky Mountains — Colorado's Front Range foothills, southeastern Wyoming, northern New Mexico and the Oklahoma panhandle, growing on rocky slopes, canyon walls and scrub at the base of the mountains, with a few disjunct populations reported in the Texas panhandle and South Dakota's Black Hills.

Status

Both wild and cultivated

Years to fruit

2–4 yrs

Growth speed

Moderate — an arching shrub reaching its mature 1–1.5 m (occasionally to 3 m) height over a few seasons rather than shooting up in one year, since its canes persist and thicken instead of being replaced annually.

Spacing

150 cm (59 in) apart — about 2.3 m² (24 sq ft) per plant

Leaf shape

Rounded, maple-like, three- to five-lobed leaves 3–7 cm across with toothed margins, on arching, completely thornless stems with flaking, reddish-brown bark.

Root system

A perennial woody crown with a fibrous root system suited to rocky, well-drained mountain soils; it does not spread aggressively by suckering or tip-layering, staying as a discrete, slowly widening clump.

Fruit description

A hemispherical, dark reddish-purple berry roughly 10–15 mm across, raspberry-type in structure (separating from a hollow receptacle) but composed mostly of seeds with little surrounding flesh — consistently reported as dry and only sparsely fleshy, though what flesh is present is said to taste good.

Propagation

By seed (stratified cold for about a month and sown in early spring), by half-ripe wood cuttings taken in July or August, or by division of the crown in early spring or autumn — it does not readily tip-layer the way true raspberries and blackberries do.

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.