Blackberry

A blackberry planting can give you twenty pounds of fruit per plant per season, or it can give you an impenetrable thicket that takes over the back fence and sends runners under the lawn. The difference is whether you prune it every year. There is no middle ground. A blackberry that is planted and then ignored becomes feral within three seasons, and at that point the only real option is to bulldoze it and start over.

The plant operates on a two-year cane cycle. First-year canes — primocanes — grow vegetatively, putting on height and lateral branches but no fruit. Second-year canes — floricanes — fruit in early summer and then die. The job of the gardener is to remove every floricane at ground level as soon as harvest is finished, usually in late July or August, and to tip the primocanes at about four feet so they branch instead of becoming tall, whippy canes that blow over in the first wind. Miss a year of this and you end up with dead canes tangled into live ones, and the whole mass becomes difficult to work with.

Thornless varieties are genuinely different to manage than thorned types. A thornless blackberry like Triple Crown or Navaho can be pruned with bare hands; a thorned variety requires leather gloves, long sleeves, and a high tolerance for getting scratched anyway. The thorned types tend to fruit more heavily and handle cold winters better, but for most home gardeners the difference in yield does not justify the misery of working with them. If you are planting your first blackberry, start with a thornless cultivar.

The other management issue is suckering. Blackberries spread by underground runners, and those runners will come up ten feet away from the mother plant if you let them. The standard fix is to mow a three-foot perimeter around the planting every few weeks during the growing season, cutting down any suckers before they establish. A root barrier buried to eighteen inches can contain the planting more permanently, but it has to be installed at planting time — retrofitting it into an established planting means digging up half the roots.

Blackberries are susceptible to several cane diseases that show up as purple or brown lesions on the canes and can eventually girdle and kill them. Most of these — anthracnose, cane blight — are worse in humid climates and in plantings with poor air circulation. Thinning canes so that no more than five or six per plant remain, and spacing plants at least three feet apart, tends to reduce disease pressure noticeably.

Harvest timing matters more than most new fruit growers realize. A blackberry that looks ripe — fully black, no red showing — may still be tart. The berry is truly ripe when it releases from the plant with almost no resistance. Fruit left on the cane for two or three days past that point often develops the best flavor, but it also becomes fragile and prone to mold. Check the planting every other day once the first berries start to color.