Blackberry

Water steadily while the berries size up

Give the planting about an inch of water a week through the season, and up to roughly 2 gallons per plant per day while the fruit is filling. Use drip or a soaker hose at the base rather than a sprinkler. Blackberry drupelets swell in the last days before ripening, so a dry spell right then gives small, seedy, crumbly fruit. Overhead water also wets the foliage and splashes anthracnose spores from cane to cane.

Feed the canes before bloom

Once growth starts in spring but well before the flowers open, band a complete fertilizer such as 10-10-10 at about 5 pounds per 100 linear feet of row along the planting, keeping it off the crowns, and water it in. The floricanes are building this year's fruit and the primocanes are building next year's at the same time, so the nitrogen has to be there before bloom draws the plant's reserves down.

Second feeding after the last picking

After harvest finishes but before autumn, make a second application of 10-10-10 at about 5 pounds per 100 linear feet along the row. The primocanes keep growing after the fruit is gone and they are the entire crop for next year, so feeding them now sets the cane size and bud count you will harvest from.

⚠ Do not push nitrogen into late fall; soft late growth does not harden off and is the first thing winter kills.

Prune blackberry canesMar – Aug

In early spring remove winter-killed cane tips; after harvest cut spent floricanes to the ground and tie in new canes. Floricanes fruit once and then decline, while open trained canes are easier to pick and less disease-prone.

⚠ Wear gloves for thorny cultivars.

Tip the new primocanes when they reach the top wire

Through the summer, pinch out the growing tip of each new primocane as it reaches the top trellis wire, about 5 feet on erect types. Do it by hand as the canes get there, not all at once. Removing the tip forces the cane to push lateral branches, and those laterals carry next year's fruit. An untipped cane grows tall and flops with few fruiting sites.

⚠ Wear gloves on thorny cultivars.

Orange rust: dig out infected plants before the pustules open

Just after the last frost, walk the patch and look for shoots that come up weak, spindly and stunted with waxy blisters on the leaf undersides that turn powdery bright orange. Dig those plants out entirely, crown and roots included, and carry them off site. Orange rust grows systemically through the canes, crown and roots, so a diseased plant never recovers and every sucker off it is infected too. Removing it before the pustules break open keeps millions of spores from seeding the rest of the planting.

⚠ Do not compost infected plants. Fungicides will not cure a plant once symptoms show, so removal is the only home-garden control. Red raspberries are immune and can replace a rust-plagued patch.

Spotted wing drosophila: pick clean every 3 to 4 days

As soon as the berries start coloring, pick every 3 to 4 days and take every ripe and overripe berry off the plant and off the ground. Refrigerate what you keep at about 35F right away, and seal culls in a plastic bag left in the sun rather than composting them. Unlike ordinary fruit flies, the female spotted wing drosophila saws through the skin of sound, ripening fruit to lay eggs, so fruit is at risk from first color onward. Every berry left on the plant becomes a nursery that reinfests the patch.

⚠ Chilling stops larval development; composting culls does not reliably kill them.

Anthracnose: copper spray as buds break

If anthracnose showed up last year, spray a copper hydroxide product labeled for brambles once the new shoots pushing from the buds are under 3/8 inch long. Wet the old canes thoroughly, not just the new growth. The fungus overwinters in lesions on last year's canes, and the spores wash onto the tender new shoots in the first warm rains. Once the shoots elongate past this stage the spray no longer reaches the source.

⚠ Liquid lime sulfur is the traditional delayed-dormant material but is no longer sold for residential use because it is caustic. Use only a copper product whose label lists brambles.

Spotted wing drosophila: spinosad only once the fruit is coloring

If sanitation alone is losing ground and you are finding larvae in picked fruit, spray spinosad after the flowers are finished and the berries are coloring. It holds for about 5 to 7 days; leave at least 5 days between treatments. Some trials report that adding sugar as a feeding stimulant improves control — only do this if the product's label allows it. Spinosad kills the adult flies before they can lay into the ripening fruit, which is the only window that matters since the larvae are untouchable once inside the berry.

⚠ Spinosad has a 1-day pre-harvest interval on caneberries and a 5-day minimum between treatments. Never spray any pesticide on a crop in flower while bees are foraging - wait until bloom is over, and apply at dusk or dawn.

Pick ripe blackberries oftenJul – Sep

Pick the berries once they turn fully black and slip off easily, chill them quickly, and keep picking every few days. Frequent harvest captures ripe fruit before birds, mold, or over-softening take it.

⚠ Handle gently; brambles bruise fast.