Summer-bearing raspberry plants are producing bumper crops of large, juicy berries. How is your raspberry season? Do you enjoy picking the fruit? If not, other than mosquitoes, what conditions make harvesting unpleasant? Has an overgrown patch made harvesting an unpleasant chore? Left unchecked, a summer-bearing red raspberry patch can become an unproductive, unattractive thicket in a short time. An overcrowded patch produces small, poorly flavored fruit, and decreased sunlight and air circulation increase the likelihood of fungal disease including anthracnose and spur blight. Annual renovation of your plants will keep them at their productive, healthy best. Late summer renovations often result in slightly more vigorous canes and larger fruit, though renovation can be done through late March of the following year. March renovation is preferable if canes may be lost to winter damage, or if plant hardiness is a concern. To renovate, simply remove canes that have already produced fruit and thin all broken or weak first-year canes. Those canes that have fruited are easy to spot at this stage, as they have numerous side branches. On the other hand, first year canes are relatively unbranched. The actual number of canes left in the row after renovation is unimportant. What is important is that the canes that are left are sturdy and strong. After thinning the old, weak, and broken canes, check your row width. Raspberry rows should be no wider than 12 inches in order to maximize light penetration and air circulation. Removing canes that grow outside the 12-inch width requires frequent attention. Summer is not a good time to fertilize raspberries and it is wise to wait until early spring to apply nitrogen. Summer is a good time to add mulch or, if you have not mulched your raspberries, put six inches of straw, hay, pine needles, compost or other organic material between the rows. Fall-bearing cultivars of raspberries, like Heritage, Redwing or Autumn Bliss, can be renovated as described for summer-bearing raspberries. If only a fall crop is desired, cut the canes entirely to the ground during the dormant season. This method provides a good way to prevent fungal diseases without the use of fungicides.
