How to Grow a Latham Raspberry

Sun

Full sun with at least 6 hours of direct light each day. More sun produces sweeter fruit and stronger cane growth. Partial shade reduces yield significantly and increases the risk of fungal disease as the leaves stay damp longer.

Drainage

Latham Raspberry needs well-drained soil. Root rot kills the canes within a season in soggy spots. Dig a one-foot test hole and fill it with water. If it drains within a few hours, the spot works. If water sits overnight, build a raised row 8 to 12 inches above grade.

Soil

Loamy soil enriched with several inches of compost is ideal. Slightly acidic to neutral conditions suit the plant. Heavy clay benefits from a thick compost amendment and a raised row, and very sandy soil benefits from extra compost to hold moisture and nutrients.

Space and the trellis

Set canes 2 to 3 feet apart along a row, with rows 8 to 10 feet apart if planting more than one. A simple two-wire trellis with 4-foot wood or metal posts at each end and crossbars at 2 and 4 feet supports the canes through summer. The trellis is optional in year 1 but worth installing before the canes get tall.

Plant where the bed gets good airflow and is not directly adjacent to wild brambles or stands of black raspberry, which carry diseases that can spread to cultivated red raspberries.

Watering

Water deeply once a week through the first growing season, applying about an inch of water at the base of each cane. Drip irrigation or a soaker hose works far better than overhead watering, since wet leaves invite fungal disease.

Once established, Latham Raspberry needs steady soil moisture from bloom through harvest in early to mid summer. A weekly deep soak during fruit development keeps berries plump rather than small and seedy. After harvest, taper back to rainfall except during severe drought.

Feeding

Feed once in early spring as new growth pushes from the soil, using a balanced fertilizer or one labeled for berries. Top-dress the row with a one-inch layer of compost as a supplement or substitute.

Avoid heavy nitrogen, which pushes lush leafy cane growth that snaps under fruit load and invites disease. Stop feeding entirely by midsummer so the canes harden off for winter.

Year 1: nothing to do

The first summer after planting, the canes grow vegetatively and produce no fruit. Let them grow tall and tie them loosely to the trellis as they reach the upper wire. Resist the urge to prune anything during this growing season.

Annual rotation in year 2 and beyond

Each summer, the canes that grew last year produce fruit and the new canes growing this year are next year's fruiting wood. After the summer harvest finishes, cut the spent fruiting canes back to ground level. They are easy to identify because they look gray-brown, woody, and dead-tipped compared to the green new canes beside them.

Leave 4 to 6 of the strongest new canes per running foot of row, and snip out any weak, thin, or crowded canes at ground level. Crowded rows produce smaller fruit and more disease.

Late winter cleanup

Walk the row in late winter before bud break and tip back the remaining canes to 4 to 5 feet tall if any are taller. Cut out any winter-damaged tips. Tie the canes to the upper trellis wire if they are not already secured.

When it's ready

Berries are ready when they turn a deep medium red and pull away from the central core (called the receptacle) with only a gentle tug. Ripe berries are slightly soft and very fragrant. Underripe berries cling tightly and taste sour. Check the row every other day at peak ripeness because berries soften quickly once ripe.

Picking and storing

Hold the berry with thumb and forefinger and pull gently. Ripe berries slip off the white core, which stays on the plant. Drop berries straight into a shallow container only a few inches deep so they do not crush each other.

Refrigerate within an hour or two of picking, and do not wash until ready to eat. Fresh berries hold for 2 to 4 days in the refrigerator. Freeze for longer storage by spreading the berries in a single layer on a sheet pan, freezing solid, and then bagging.

Bird and animal protection

Birds discover ripe raspberries fast. Drape lightweight bird netting over the trellis as berries start to color and remove it after the harvest finishes. Reflective scare tape and motion-activated sprinklers help in lighter pressure areas.

Cane blight or spur blight

Brown or purple lesions on the canes that girdle and kill sections. Prune affected canes back to healthy wood and disinfect pruners between cuts with a quick wipe of rubbing alcohol. Improve airflow by thinning the row to no more than 6 strong canes per foot and remove all spent canes to the ground each fall.

Spotted wing drosophila

Tiny fruit flies that lay eggs in ripening berries, producing soft mushy fruit with white maggots inside. Harvest berries the moment they ripen rather than letting them sit. Drop overripe or damaged berries into a sealed bag and discard. Fine-mesh netting (0.98 mm hole size) draped over the row during fruit development excludes the adults.

Japanese beetles

Metallic green and copper beetles chewing the leaves into lace and damaging fruit in midsummer. Hand-pick beetles into soapy water early in the morning when they are sluggish. Avoid pheromone traps near the bed, which attract more beetles than they catch. Heavy infestations respond to neem oil or kaolin clay, applied in the evening to avoid harming bees.

Raspberry cane borer

Cane tips wilt and droop in a hooked shape during early summer, with two rings of small punctures a few inches below the wilt. The adult beetle lays an egg between the two rings, and the larva burrows down the cane. Cut the wilting tip off a few inches below the lower ring before the larva descends, and discard the trimmings.

Yellow leaves with green veins

Iron deficiency, common on alkaline soils where iron is locked up in the soil chemistry. Apply a chelated iron foliar spray for a quick fix and amend the row with elemental sulfur or acidic compost to lower the soil pH over time. Targeting a soil pH of 6.0 to 6.5 keeps iron available.

Powdery mildew on leaves

White powdery film on the foliage in humid weather. Prune to maintain airflow through the row, water at the base rather than overhead, and remove badly affected leaves. Horticultural oil or potassium bicarbonate sprays control heavier outbreaks.

Anthracnose

Sunken purple-bordered spots on canes and leaves that expand into larger gray patches. Remove infected canes at the base and burn or bag them, since the fungus overwinters on plant debris. Avoid overhead watering and improve airflow by aggressive thinning.

Crown gall

Rough warty growths at the base of canes near the soil line, caused by a soil-borne bacterium. Pull and discard infected plants since there is no cure. Avoid replanting raspberries in the same spot for at least 3 years and source new plants from a reputable nursery to avoid introducing the bacterium.

Few or small berries

Usually caused by overcrowded canes, under-watering during fruit development, or fertilizing with too much nitrogen. Thin the row to 4 to 6 strong canes per running foot, water deeply through bloom and fruit development, and stick to a single balanced spring feeding.

Suckers spreading beyond the row

Latham Raspberry spreads aggressively by underground shoots that pop up several feet from the parent. Mow or pull suckers outside the row twice a season to keep the patch in bounds. A buried plastic or metal root barrier 12 inches deep along the row edge stops most spread.