Latham raspberries bear fruit on their 2-year-old canes. Though some growers do not prune bramble fruits like Latham, pruning increases yields and enhances the quality of the fruit. Simple trellis systems combined with pruning control the size of the beds and contribute to the health of the plants. This combined approach also simplifies harvesting by bringing fruiting canes to the outer edges of the bed. Latham raspberries require pruning twice a year.
Pruning Latham Raspberries
Prune newly planted raspberry canes back to only 6 inches tall. New canes sprout around the old stumps once the plants adapt to the new ground. Raspberries travel when canes grow so long that tips arc to the ground and take root. To control the size of the berry bed trim tall canes back to just under 5 feet in height in late spring of the first year.
Set trellis posts 15 feet apart in the raspberry bed. T-shaped supports should suspend two parallel wires 28 inches apart and 3 feet above the ground along either side of the raspberry bed. Use pliers to wrap the fence wires to the posts.
Tie canes to the wires of the trellises in the fall of the first year. Bending the canes outward to the support wires opens up the center of the bed for next year's new canes. Trellises also place fruit within easy reach for harvesting.
Prune old canes back to the ground after harvesting ends in their second year. Leaving old canes only robs new canes of nourishment. Second-year canes die back naturally after fruiting. If left until winter, the old canes could host raspberry disease organisms and insect pests.
Cut out any new canes sprouting outside the bounds of the raspberry bed. Latham raspberries grow well in a space between 18 inches and 2 feet wide. Each year after harvest cut out all canes which bore fruit. Cut tall canes back and tie new canes to the trellises in the fall.