Black Gem

Black Gem (APF-205T) is one of the primocane-fruiting blackberry cultivar from University of Arkansas, United States.
Black Gem is moderately vigorous and prolific blackberry. Both primocanes and floricanes are erect in growth habit. The plants are fully thornless. Primocane fruit and flowers are borne on the cane terminus or on lateral branches if primocanes are tipped, and fruiting continues down the primocane during the season. Canes usually attain a length of 1,5 to 1,8 m prior to the appearance of flower buds. The canes are best managed if trained to a hedgerow and a trellis with supporting wires used to prevent canes from falling over due to wind or heavy fruit loads.
Flowers are large (~ 3.3 cm) and have a white color. The floricane bloom period of the Black Gem begins at the middle of April. The first ripe fruit date is the beginning of June. Floricane fruit of the Black Gem has a harvest period of 35 days.
Primocane bloom period begins at the middle of June. Primocane first ripe fruit date is the third week of July on tipped primocanes. Primocane fruit harvest can be dependent on environmental conditions, most importantly temperatures being below 32 C to allow fruiting. Primocanes fruit during the season until autumn frost.
Fruit yields of the Black Gem cultivar on floricanes are about 5 kg per plant if the floricanes are retained for fruiting. Fruit yields of the cultivar on primocanes average 0,8 kg per plant.
The fruit shape is ovate , bright glossy black in color and very attractive. The floricane fruit is large, about 7 g. Primocane fruit averaged 9 g. The berries have a very soft inner core or torus (receptacle), which provides for a very melting texture. The fresh fruit rates very good in flavor.
Black Gem blackberry is hardy to minus 15 C and possibly lower.

1. Avoid wet area when planted;
2. Annual pre-emergence and postemergence herbicide applications;
3. Annual spring nitrogen fertilization (56 kg/ha) using ammonium nitrate;
4. Tipping primocanes at 1.1 m height two times each season usually in mid-June and late July or early August;
5. Dormant pruning of primocane-fruiting plants must include removing dead floricanes and removing primocane tissue to a point below the fruiting (flowering) area on the primocanes;
6. Dormant pruning of floricane-fruiting plants must include removing dead floricanes and pruning lateral branches to ~0.4 m in length;
7. Use drip irrigation;
8. Use sun screens and grids. Plants are fertile and abundant unless temperatures at which temperature exceed 32 ° C (90 ° F) can damage flowers and anthers and pollen production can be reduced;
9. A single application of iron sulfate in late fall and lime sulfur in early spring.