Himalayan Blackberry and Its Native Look-Alikes

Himalayan Blackberry (Rubus armeniacus)

Working on forest restoration has given me a grudging respect for Himalayan Blackberry. In full sun it produces masses of flowers that swarm with bees. The delicious fruit feeds birds and small mammals that take refuge in its impenetrable thickets. Armed with a formidable array of nasty thorns it spreads by both seeds and runners. The runners include both lateral roots that can extend several feet underground and arching overhead runners that can extend up to 20 feet.

Himalayan Blackberry is not as invasive when growing as isolated plants under the shaded forest canopy, but in sunny edges it can overwhelm other plants and produce the massive patches that most of us in the Puget Sound Region are familiar with.

Native Look-Alikes

Trailing Blackberry (Rubus ursinus)

Himalayan Blackberry, when small, is easily confused with the native Trailing Blackberry. To tell them apart, I focus on the leaves. Himalayan Blackberry leaves grow from short stems that emerge alternately from the main vine stems in groups of five. Trailing Blackberry leaves grow in the same way but in groups of three. If I’m looking at a Blackberry vine, and I’m not sure which it is, if the leaves are in groups of three, I assume it’s a Trailing Blackberry and leave it alone.

Telling the Native Trailing Blackberry Apart from the Invasive Himalayan Blackberry

The Trailing Blackberry has leaves in groups of three and a pale stem that has small thorns.

The Himalayan Blackberry has leaves in groups of five.

Three other features distinguish the two species:

If the stem is cut, the cross-section of the Himalayan Blackberry is shaped like a polygon while that of the Trailing Blackberry is round.
The thorns on the Himalayan are generally much more formidable than those of the Trailing Blackberry.
The flowers also differ (see photos below).

Himalayan Blackberry has a stem that is polygonal in cross section and armed with formidable thorns.

Trailing Blackberry has round stems. Prickles are smaller than the Himalayan Blackberry. Color of stem is a milky blue-green.

The petals of the Trailing Blackberry are long and thin and pure white.

The broad, flimsy petals of the Himalayan Blackberry often have a pinkish cast.

Blackcap Raspberry (Rubus leucodermis)

The native Blackcap Raspberry can also be confused with the Himalayan Blackberry. The Blackcap has a similar size and shape and also has leaves in groups of five. However, the leaves of the Blackcap are shaped differently, and the vine stems have even more thorns than the Himalayan. The Blackcap’s vine stems are such a light green they can appear almost white. (Another common name for this plant is Whitebark Raspberry.)

Some leaf clusters of the Blackcap Raspberry are in groups of five like the Himalayan.

The stem of the Blackcap Raspberry is a pale, milky blue green with large sharp thorns.

Salmonberry (Rubus spectabilis)

The leaves of the Salmonberry can look similar to those of the Himalayan Blackberry, but the Salmonberry is a shrub with woody stems, not a vine.

Note that by late November the leaves of the Salmonberry are either yellow or have already fallen, whereas those of the Himalayan Blackberry are still green making that a good time of year to spot Himalayan Blackberry growing in patches of Salmonberry.