Deborah Brown, Extension Horticulturist
Our slow, cool spring means there's plenty of time to plant trees and shrubs in your landscape. If you've got a sunny location with well-drained soil, consider growing raspberry bushes in your own yard. The plants are not very demanding. Red raspberries are perfectly hardy here, and they produce lots of fruit when planted in a good location and given a modest amount of care.
You needn't get into fruit growing in a big way to enjoy raspberries. As few as four or five well-tended bushes will yield plenty of berries to sprinkle on your cereal or ice cream for several weeks each summer, and perhaps again in autumn if you plant one of the ever-bearing (also called fall-bearing) varieties.
Raspberry plants aren't particularly fussy about the type of soil they grow in, as long as water doesn't puddle there. (Poorly-drained soil encourages root rot, or at the very least, poor root growth.) If your soil is quite sandy, however, it would be a good idea to incorporate lots of baled (dry) peat, compost, or other organic matter into it before planting, to help maintain moisture and nutrients. Without adequate moisture, your berries will be smaller and less juicy.
Before you plant, be sure to get rid of weeds, especially perennials such quackgrass or creeping charlie. Use a non-selective herbicide such as glyphosate (sold as RoundUp) that allows you to plant within days of application. The job will be much more difficult once the raspberries are in, because most herbicides that kill tough, perennial weeds will also kill your raspberry canes.
Plant red raspberry bushes two to three feet apart. If you put in more than one row, space the rows at least six feet apart. Allow new canes to fill in, but leave only four or five sturdy canes per foot of row, to avoid ending up with a miserable "bramble patch" that's only marginally productive. When you allow too many canes to develop they'll compete for available water and nutrients. Air circulation will also be reduced, so leaves dry more slowly after rainfall, giving fungal diseases a better opportunity to develop.
Fertilize newly planted raspberries by working 1/4 cup of high nitrogen fertilizer into the soil around each plant. In following years, use about 1/2 cup of 10-10-10 per plant, early each spring. If you prefer an organic approach, fertilize with well-composted manure before you plant, and again every following spring. Incorporate the manure at the rate of 3 1/2 cubic feet per 100 square feet.
It's a good idea to mulch your raspberries with several inches of wood chips, grass clippings or shredded leaves. Mulch helps retain soil moisture and blocks the light that's needed by many weed seeds to germinate.
Plan on watering during any dry weather from spring right through the completion of fruit harvest. These plants need a total of 1 to 1 1/2 inches of water every week (in the form of rainfall or irrigation) to ensure the growth of plump, juicy berries.
Canes of ever-bearing varieties produce fruit their first year in fall, then a second time the following summer. Canes of summer-bearing varieties don't produce fruit at all their first year, only the second. Regardless of which type raspberries you plant, prune all canes that have produced fruit in June or July smack down to the ground right after you've harvested the last few berries. Individual canes that fruit in early summer will never bloom and fruit again. New canes will arise from the roots to take their place, however.
There are many good summer-bearing raspberry cultivars available. ‘Boyne', ‘Festival', ‘Liberty' and ‘Killarney' are hardy throughout the state; ‘Newburgh', ‘Haida' and ‘Sentry' are only suited to the southern third. Ever-bearing varieties ‘Fallred', ‘Redwing', ‘Summitt', ‘Fallgold' (a yellow variety) and ‘Autumn Bliss' are hardy border to border, though early cold weather may eliminate their fall crop in northern regions.
