Late summer marks the prime season for picking blackberries in the Northwest. Most of those are from the invasive Himalayan blackberry bush, but there is also a blackberry species native to the region.

Summer is here, and that means blackberries are ripening on the vine. Here in the Northwest, there are multiple species featuring delectable, juicy berries, but only one is native to the region.

The trailing blackberry — also known as the California blackberry, Pacific blackberry or Pacific dewberry — distinguishes itself through a slender, biennial vine, pale green to bluish-purple in color, with tiny thorns all along its length. Some vines may exceed 6 feet in length, and each plant may produce several of these from a central perennial root system.

Leaves and berriesThe leaves of trailing blackberry generally have three leaflets, though one or five may occasionally be seen. These are dark green above with a pale green to white underside.

Each leaflet is oval in shape with a pointed tip and a deeply serrated edge that has larger serrations interspersed with groups of smaller, finer ones. They generally will not reach more than about 4 inches in length. This species is deciduous, losing leaves over winter before growing new foliage in the spring.

First-year vines are not fertile; they will not produce flowers until their second year, after which they die. Like many similar species, the trailing blackberry has a flower with five small, slender white petals.

The center is pale green to yellow with several dozen anthers on the flowers of male plants. Female plants are the only ones to bear small berries, about 3/4 inch or so long at the largest. Berries start out green, darken to red and finally ripen at a deep purple to black hue. While smaller than commercially available blackberries, they are quite sweet and flavorful when ripe.

They are not true berries, but are instead composites of several tiny round drupelets each with its own seed, which is typical of other Rubus species.

Trailing blackberry can grow quite quickly, and although it may clamber over other plants, it generally does not out-compete them to the point of becoming a monoculture. It is also a quite hardy plant and can colonize disturbed ground with ease as long as there is plenty of sunlight.

The vines can become a bit of a tripping hazard in places with high foot traffic, but are easily trimmed back without killing the entire plant. In addition to seeds, trailing blackberry can also grow colonies of clones wherever its vine touches the ground.

Spotting the differenceIn its native range, trailing blackberry is a rather unique plant. It may be confused with the invasive Himalayan blackberry. However, the latter grows on large, thick canes up to 30 feet long that can grow tall and arch over, and which create massive thickets.

The leaves of the Himalayan blackberry are also larger and rounder — up to 8 inches long — and typically have five palmately compound leaflets instead of three. Himalayan blackberry flowers have rounder petals, and the berries are much larger.

Cutleaf or evergreen blackberry is another invasive species found within trailing blackberry’s range. Like Himalayan blackberry, the cutleaf species also grows thick, long canes. It is mainly distinguished by its leaves, which have three leaflets that are deeply serrated/toothed and have a jagged appearance — hence the name.

Black or whitebark raspberry has berries which superficially look like those of trailing blackberry. However, once again the canes of this species are thicker and woodier than the trailing vines, and they have a distinctive white to pale purple glaucous coloration. The leaflets are larger than those of trailing blackberry, with first-year leaves having five pinnate leaflets, and second-year having three.

The berries are larger and rounder, generally not exceeding 1/2 inch in diameter. The overall appearance of the plant is of a taller, more upright shrub than a series of vines trailing over ground and other surfaces.

The berries of trailing blackberry are edible and the leaves may be made into tea. If cultivating this species, be aware that it grows quite quickly, though it can be trained up a trellis with some effort.