RUBUS: Salmonberry, Thimbleberry
To be honest, some of our native brambleberries are not for the faint of heart or tidy-small-space gardener. The wild Rubus is a romping, happy grower that, while providing much beneficial cover and shelter for songbirds, can easily become a thicket when given sufficient moisture and nutrients (if you've ever grown cultivated raspberries you have the idea, but the amount of spread is greater for the wilder members of the group). However, if you have an untamed hedgerow or left-on-its-own shady area in your landscape for the sake of attracting birds to your garden, then a native Rubus might be the perfect addition.
The genus contains both shrubs (R. parviflorus, R. spectabilis) and groundcovers (R. lasiococcus, R. pedatus), suitable for a variety of conditions, and all virtually pest and disease free.
The two shrub varieties are more commonly available than the groundcovers.
R. parviflorus – Thimbleberry
This shrub is deciduous, thornless, and generally tops out at about six feet, spreading laterally by underground, woody rhizomes. Largish, maple-shaped leaves and papery white blossoms begin to appear in late-spring. The berries that follow are red when ripe, and separate from their receptacles like cultivated raspberries, giving them the thimble shape of its common name. This is the one Rubus that can be found east of the Cascades, so it is perhaps more tolerant of drier, sunnier conditions, though it will still thrive in wooded settings. Can grow in full sun to partial shade, and because it so readily forms suckers it is a good plant for erosion control on untamed slopes. Flowers attract butterflies and birds appreciate its protective cover along with the berries. Some people also like the berries, though some find the taste rather bland. (Photo credit of Thimbleberry Bush - Dennis Ancinec)
R. spectabilis – Salmonberry
Though salmonberry can grow in full sun with sufficient water, this is the Rubus most commonly found along our west Cascade hiking trails. The upright, arching branches vary from nearly thornless to quite thorny, and are apt to grow to ten feet, if left unpruned. It blooms in early spring shortly before the full development of the large, palmate leaves. The flowers are an eye-shocking pinkish-purple that are a magnet for hummingbirds, and are a striking contrast to the bright green of the new leaves that follow. The fruit, which also resembles the raspberry, is small, orange to red. The flavor can vary widely, but it is generally considered tastier than thimbleberry. But even if you don't like the taste, birds finding their way to your garden definitely will. Found along streams and in moist woods, this is the one for wetter areas. It too will create a formidable thicket that birds find good protective cover (though slightly drier conditions might keep the spread a bit more in check. Maybe. A bit.)
There are two groundcover species, not commonly found in nurseries, but that are considered garden-worthy:
R. lasiococcus – Creeping Raspberry
This groundcover Rubus only gets about four inches tall, but each stem can extend as far as six feet, sending its roots into the ground at each node, similar to our native strawberries. The three-leaf clusters are semi-evergreen in milder winters/locations. Small white flowers appear in summer, followed by tiny red, raspberry-shaped fruit held so close to the ground that small creatures may get to these berries before you can. (This one should be grown more for its plant quality rather than its edible potential.) This plant can grow in full sun to full shade, moist to somewhat dry settings, along paths or tucked in amongst shrubs and other perennials.
R. pedatus – Strawberry Bramble
This Rubus is a smaller, mat-forming groundcover, with stems reaching only three feet, also rooting at the nodes, with one-inch tall stems rising from each node, topped with small white flowers. The small fruits that follow in the summer are generally in tiny clusters of up to six fruits, bright red in color and are considered quite tasty. If you have a wet spot in your shade garden, this might be just the thing as it wants full to part shade, dappled light at most. In the wild it is found along streams and in mossy forests, so will not tolerate dry conditions.
There is also one wild, trailing blackberry (R. ursinus) that, while arguably one of the best tasting blackberries, is the prickly vine that trips hikers along the trail and is such an aggressive grower that it would rapidly outstay its welcome in any garden setting.
Common Names: Salmonberry, Thimbleberry, Brambleberry
Origin: From southern Alaska into California, generally hugging the western-most portions of this region; R. parviflorus is common on the other side of the Cascades and ranges farther east.
Characteristics: Upright shrubs or groundcovers; some with thorns and some without; leaves range in size but all palmate; flowers in spring-early summer, followed by berries attractive to birds and of varying palatability to humans. All species readily spread by runners or rhizomes; groundcovers becoming mat-forming and shrubs becoming dense thicket over time.
Culture: Depends on species, but for the most part grow best in sun to partial shade and moist to wet conditions.
Maintenance: Pruning the shrub forms can keep them to five or six feet in height (as opposed to eight to ten feet if left un-pruned) and help prevent leggy growth.
Pests & Diseases: There is the occasional bout of powdery mildew in areas with limited air circulation, and slugs will sometimes munch on the fruit of the groundcover varieties, but for the most part appear to be pest and disease free.