Brambles are defined as any species belonging to the Rubus genus. This definition covers a large number of plants found growing in the woods and fields surrounding us. Practically speaking, however, the brambles of concern to the home gardener are raspberries (red, black, and purple), blackberries (thornless and thorny), and some of the recently developed hybrids such as tayberries.
Brambles are, in some ways, the perfect home garden plant. They are relatively easy to grow, requiring little more than a patch of full sun and some well-drained soil. They are highly perishable or often unavailable commercially, so home planting assures a supply of this delicious treat.
Plants belonging to the Rubus genus typically have perennial roots with shoots that are biennial. This means that the shoots (called "canes") grow vegetatively in the first growing season. However, some raspberries have the capability of producing a crop on the current season's growth as well. This crop is produced in the fall after the new canes have reached their full height.
Raspberries and blackberries are the two most common bramble crops. Red, black, and purple raspberries are the three most commonly grown raspberry types. The word "type" is used intentionally because the differences among them include not only the color of the fruit, but also the growth habit (and hence the cultural practices), disease problems, and other characteristics.
Black raspberries initiate new canes from the crown of the plant rather than from root suckers. Because of this, they are grown in a "hill" system: each plant is grown independently, with pruning and maintenance done on a per-plant basis. They require summer tipping, unlike red raspberries, because individual canes will grow to unmanageable lengths. Black raspberries bear their fruit in late June through July and are the most winter tender of the raspberries.
Eastern blackberries can be thorny and erect, or thornless and trailing. Thornless types are much more cold sensitive (to 0°F) and can be grown only in the southern or warmer portions of Pennsylvania. However, cold sensitivity of many varieties may be due to failing to survive fluctuating spring temperatures, rather than failing to survive winter temperatures when the plants are fully dormant. Because of their trailing growth habit, they require trellising. Thorny types often have excellent fruit quality, but the thorns are brutal. Generally, thorny types of blackberries will tolerate temperatures to about -5°F. They do not require trellising. The recent development of primocane-bearing blackberry varieties may allow the production of cultivated blackberries in the coldest regions of the state. Because the canes are mowed to the ground each spring, winter survival of the canes is no longer an issue.
Gold raspberries also are available, but they are not widely grown. Efforts are under way to develop a commercially viable gold raspberry (see "Variety Selection").
Purple raspberries initiate new canes predominantly from the crown but may sucker between plants as well. They are grown essentially as black raspberries are and have intermediate cold-hardiness.
Red raspberries can be either of two types. Summer-bearing red raspberries bear their fruit from late June to August. They have the typical biennial life cycle of a bramble, so their canes die after fruiting. Primocane-bearing types, such as Heritage, fruit during the first year, as mentioned above. Also called "everbearing" raspberries, they will fruit again in the spring on the buds below those that fruited the previous fall. Because both of these red raspberries produce new canes (suckers) primarily from the root system, they usually are grown in a hedgerow. They are the most winter hardy of the raspberries.
Tayberries were bred by crossing a blackberry with a raspberry. The flavor of the fruit reflects this parentage, and many people feel that a ripe tayberry is the most flavorful bramble of all. Unfortunately, tayberries are very soft when fully ripe, so they don't lend themselves to well to growing in a manner similar to thornless blackberries and require similar planting, training, and pruning techniques.
Other brambles, most of which are either hybrids among Rubus species or specific varieties of blackberry, such as Boysenberry, Loganberry, Marionberry, and Ollalaberry, are grown extensively in the Pacific Northwest of the United States. They have excellent fruit quality but are not well adapted to environmental conditions in Pennsylvania and should not be grown here. Their most limiting characteristic is their cold-tenderness