Culture
Best grown in moist, organically rich, slightly acidic, well-drained soil in full sun to part shade. Intolerant of wet soils. Raised beds should be considered in areas with heavy clay soils. Plants are perennial but canes are biennial. For established shrubs, tip-prune new vegetative (non-fruiting) canes in summer. Immediately after fruit harvest, remove all canes that fruited to the ground. In late winter to early spring, remove any canes damaged by winter and thin the remaining canes to 4 or 5 strong, well-spaced canes plus trim the laterals thereof. Plants generally perform best when staked.
Noteworthy Characteristics
Blackberries are aggregate fruited brambles native to temperate regions around the world. The biennial canes emerge from a perennial rootstock and can take on a sprawling to erect habit. Most blackberry cultivars available today are hybrids of multiple species in the genus Rubus. Blackberries can be distinguished from raspberries by certain characteristics of their aggregate fruits. When blackberries are picked off the canes, the receptacle (central attachment point for the fruiting body) remains inside the aggregate fruit. Raspberries have hollow centers. The drupelets (small, individual fruits that make up the aggregate fruit) of blackberries are smooth while the drupelets of raspberries have small hairs. Modern blackberry cultivars are divided into three main groups based on their growth habits: trailing, semi-erect, and erect. These can be further divided by their fruiting habits and whether the canes have thorns or are considered thornless. Cultivars that produce a single crop on only two year old canes are called floricanes. "Everbearing" or primocane varieties will produce fruit on two year old canes as well as a smaller, late crop on new canes.
Genus name is the Latin name for brambles (blackberry and raspberry).
‘Triple Crown’ is a semi-erect, thornless blackberry cultivar. This is a self-fruitful, free-standing, thornless shrub that produces one crop of fruit per year. Clusters of white, 5-petaled, rose-like flowers in spring give way to firm, glossy blackberries of excellent eating quality that mature in summer (early July in St. Louis).
Problems
Anthracnose, botrytis and verticillium wilt can be serious disease problems. Cane borers and crown borers are potentially serious insect pests.
Uses
Although the flowers are attractive, this blackberry is grown primarily as a food crop and it not considered appropriate for ornamental use.