Raspberries

Raspberries are delightful fruits that grow well in Wisconsin both naturally and in cultivation. Plants consist of thorny canes that grow perennially and can be either summer-bearing or fall-bearing.

Summer-bearing cultivars produce one large crop between early July and August. Fall-bearing cultivars produce one large crop in the fall, generally around late August. Fall-bearing cultivars are also known as ever-bearing because each cane produces a large crop of fruit in the fall the first year and a small crop of fruit in the summer of the second year. When there are canes of varying maturity, the same plant produces fruit through both seasons. Depending on the pruning technique fall-bearing cultivars will produce either one crop or two.

Raspberries are self-fertile meaning the pollen of one cultivar can pollinate flowers of the same cultivar. Flowers must be pollinated to produce fruit, which about 90-95% of pollination is done by bees.

Light

Prefer full sun, but will tolerate some shade, though produce less fruit.

Planting

Dig a hole wider than the root ball, but at the same depth as the container it is in. Best to plant in a narrow hedgerow.

Soil

Prefers fertile, well-draining soil, such as sandy loam. Use compost to amend soil.

Water

Water well after planting and supplement water as necessary to keep soil moderately moist, but not too wet.

Fertilizer

Fertilize with a balanced fertilizer, usually a 10-10-10, such as Espoma Garden Food, according to directions.

Pruning

Raspberries need to be pruned yearly.

Summer-bearing cultivars can be pruned in the spring by removing dead canes and then pruning back existing canes by no more than 25% from the tip.

Fall-bearing cultivars are best pruned by mowing down all of the canes in March with the lawn mower. This is the least time consuming method and produces the largest fall crop, but means that it will not produce a summer crop. To get two crops, prune back to the ground only the canes that just produced fruit, either just after the summer crop is finished or early spring. Then prune remaining canes back by no more than 25% from the tip in the spring.

Grooming

Weeding throughout the summer helps increase yields.

Mulch

Provide 2-4 inches of mulch to cool the soil, conserve moisture, and prevent weeds.

Problems

Raspberries generally have minimal pest and disease issues.

Japanese beetles are particularly attracted to raspberries, and can cause damage to the leaves. Refer to the article on Japanese Beetles for more information and treatment.

A recent pest of concern is the Spotted Wing Drosophila, which has been spreading across Wisconsin since 2010. It is an invasive species of fruit fly that lays eggs in ripening fruit that develop into tiny white larvae. Fruit tends to rot quickly and white larvae can be seen inside the fruit tissue. Be on the lookout for developing larvae, and if you suspect it’s presence you can submit a sample to the UW-Madison Insect Diagnostic Lab by following directions here. More information and ways to monitor can be found on the UW Extension website.

Raspberries
Cultivar
Fruit Color
Fruiting Type
Fruit Size
Height/Spread
Approx. Ripening Time
Autumn BlissRedEverbearing/Fall-bearingLarge fruit.Grows 60-72 inches high, with a 36-48 inch spread.Ripens mid-August
Fall GoldGoldEverbearing/Fall-bearingVery sweet fruit.Grows 4 feet tall, with a 3 feet spread.Ripens late August.
Heritage RedRedEverbearing/Fall-bearingMedium sized fruit.Grows 5-6 feet.Ripens late August.
K81-6RedSummer-bearingVery large, firm fruit.Medium-tall canes.Ripens mid-late summer.
Royalty PurplePurpleLate Summer-bearingExtra large fruit.Grows 48-60 inches tall, with a 24-36 inch spreadRipens in August.