Expected Yield:  6 to 7 pounds per hill Hardiness:  +5 to -20 F, depending on cultivar Plant spacing:       Erect cultivars:  5 feet apart in rows 10 to 12 feet apart      Trailing cultivars:  5 feet apart in rows 8 to 10 feet apart

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Erect Blackberries

Erect blackberries are generally more cold hardy than trailing types and are better adapted to Idaho growing conditions.   Even the most cold-hardy blackberries, however, cannot tolerate temperatures lower than about -20 to -25 F.  The following blackberries have proven suitable for some Idaho locations.

Erect blackberries can be grown free-standing, although one or two trellis wires can help keep the bushes more manageable, particularly in snow country.

Cultivar	Cold Hardiness	Fruit Characteristics					Disease Resistance
		Ripening	Size	Flavor	Fresh Use	Cooking	Root Rot	Spur Blight
Thornless Blackberries
Chester	-20	3	M	G	G	E	4	4
Dirksen	-15	3	L	G	G	E	4	4
Navaho	-10	4	S-M	G	G	E	4	4
Thornfree	-10	4	L	E	E	E	4	4
Thorny Blackberries
Darrow	-25	2	S	F	F	G	4	4
Illini Hardy	-20	4	M-L	G	G	E	4	4
Ripens: 1 = early - mid summer, 2 = mid - late summer, 3 = late summer - early fall, 4 = early - late fall Fruit size: S = small, M = medium-sized, L = large Fruit flavor, Fresh use, and Cooking: P = poor, F = fair, G = good, E = excellent Disease resistance: 1 = very susceptible, 2 = susceptible, 3 = moderately resistant, 4 = very resistant

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Trailing Blackberries

All of the blackberry cultivars listed above are erect types.  Trailing blackberries (also known as dewberries) include such cultivars as Marion, Logan, Hull, Bababerry, Tayberry, and Tummelberry.  Trailing blackberries are not reliably cold hardy in Idaho growing conditions.  Most are injured or killed by  winter temperatures around 0 F. In Northern Idaho tests, the cultivar Marion ripened early and had the best flavor of all blackberry cultivars.

Trailing blackberries are always supported on trellises. One method of training them is to form wheels of canes. When the new primocanes are about 18 inches long, tie them together into bundles. As the canes continue to grow, wrap them into a circle and support them by a hook on the top trellis wire (do not wrap the canes around the wires).

If your site experiences temperatures below about +5^o F, lay the wheels of canes on a plastic sheet on the ground and cover them with straw or other mulch after the leaves have dropped in the fall. Mulching the canes protects them from cold winter temperatures. If you mulch, set out baits or traps to control mice and voles. In early spring, rehang the wheels of floricanes and begin forming new primocane wheels.

After harvest, cut off the expended floricanes near the ground, leaving the primocanes that will bear next year’s crop. This method is obviously best suited to home gardeners. For commercial operations, trailing blackberries are not  recommended for the Inland Northwest and Intermountain West.

The following illustration shows how to manage trailing blackberries for home gardens in areas with cold winters.

Training trailing blackberries. A). Early summer. Shape primocanes into wheels. As the primocanes grow during the summer, continue to wind the new growth onto the wheels. B). Winter. Lay wheels of canes on the ground and mulch to protect them from freezing injury. C). Spring. Rehang cane wheels (floricanes). Begin forming new primocane wheels. After harvest, cut floricanes off at the ground.