Blackberries are highly amenable to propagation, meaning that increasing the number of plants in your garden is a straightforward process. Their naturally vigorous growth habit, which includes both underground spreading and cane-tip rooting, makes them excellent candidates for home multiplication. This ease of reproduction ensures that a single healthy plant can rapidly become the source for many new ones, often yielding successful results even for the beginner gardener. The ability to clone a plant to retain the exact characteristics of the parent, such as thornlessness or specific fruit quality, is a significant advantage of using these vegetative propagation methods.
Harnessing Natural Plant Division and Suckers
Many erect blackberry varieties produce “suckers,” which are new shoots that sprout from the plant’s root system at a distance from the main crown. These suckers represent a complete new plant that can be easily separated from the parent during the dormant season, typically in late winter or early spring before new growth begins.
To harvest a viable sucker, identify a shoot that has grown a few inches away from the original plant and is showing healthy top growth. Using a sharp spade, sever the root connection between the sucker and the parent plant, ensuring that the separated section retains a good portion of its own root structure. This technique is arguably the simplest way to propagate, as it requires minimal preparation.
If the main plant is well-established, an alternative approach is crown division, where the entire root mass is dug up and split into smaller sections. Each divided piece must contain sufficient roots and at least one bud or cane to ensure successful growth after transplanting. Dividing the crown is best performed during the plant’s dormancy to minimize stress and give the new divisions time to establish before the growing season.
Propagating with Stem and Root Cuttings
Propagating blackberries using cuttings involves two distinct techniques based on the maturity of the plant material. Root cuttings are taken from mature roots during the plant’s dormant period, typically from late fall to late winter. The roots should be harvested carefully, aiming for sections that are approximately pencil-thickness and cut into pieces about 3 to 6 inches long.
To ensure proper orientation when planting, a common technique is to make a straight cut on the end nearest the crown and an angled cut on the end further away. These root sections should be planted horizontally or vertically in a well-draining medium, covered lightly with about an inch of soil. If planted vertically, the straight end should be inserted slightly into the soil. A period of cold storage (a few weeks around 40°F or 4°C) can improve the success rate for larger root sections before planting them in a warm environment to encourage shoot growth.
Softwood stem cuttings are taken from new, flexible growth during the growing season, usually in late spring or early summer. A cutting of about 4 to 6 inches is prepared by removing the lower leaves to expose the nodes. While not always necessary, dipping the base of the cutting in a rooting hormone can increase the speed and number of roots formed. These cuttings require a highly humid environment and a consistently moist, well-draining medium to prevent desiccation while the new root system develops.
Encouraging Growth through Tip Layering
Tip layering is favored for trailing or semi-erect blackberry varieties, which arch their canes toward the ground. This technique encourages the tip of a current-season cane to develop roots while remaining attached to the parent plant. The best time to perform tip layering is in late summer or early fall when the canes are long and flexible.
The process involves bending a healthy cane down and burying the tip (the last 4 to 6 inches) in a shallow trench about 2 to 3 inches deep. Secure the buried section with a U-shaped wire pin or a small rock to keep it firmly in contact with the soil. Leaving the last few inches of the cane tip exposed ensures photosynthesis continues.
The buried tip forms a dense root system over the fall and winter while still receiving nourishment from the parent plant. The rooted plant should be left attached until the following spring, when the cane is severed using sharp pruners. The new plant can then be carefully dug up and transplanted to its permanent location.