Raspberries require full sun and well-drained soil. Soil testing is recommended to determine proper fertilizer application and liming requirements.
To avoid powdery mildew, maintain good air circulation, and prune vigorously in spring and summer after fruiting. To keep birds from stealing your crop, install lightweight bird netting. Also, mulch in summer to retain moisture and suppress weeds.
Red Raspberries
The raspberry plant (Rubus idaeus) belongs to the rose family along with apples, pears, cherries, peaches, plums, and roses. Raspberries are cane berries, not true berries, because they come from an aggregate of many ovaries instead of coming from a single one.
A single raspberry has anywhere from 50 to 150 drupelets that are grouped together. When ripe, raspberries are bright red with a sweet taste. They are available fresh or frozen in supermarkets, and are a popular choice for home gardeners.
Raspberry plants can be grown in raised beds or in the ground with a rich, well-draining soil. Since they don’t need cross-pollination to produce fruit, growing several different cultivars will give you a longer harvest season and a variety of flavors.
The main types of red raspberries are summer-bearing and everbearing (primocane-fruiting). Summer-bearing varieties grow vegetatively in their first year and fruit on second-year canes. The canes that bear fruit are called floricanes, and they die after the fruiting period. Everbearing varieties produce flowers and fruit on the lower portions of first-year canes in the fall, but they also produce a light summer crop on their tips.
Choose a disease-resistant cultivar for your planting site. Consideration of climate, pests and diseases will help you decide if a particular raspberry is right for your gardening conditions.
If you choose a summer-bearing cultivar, you will need to install a trellis for support. Set treated wooden end posts at each end of the row (3 to 4 feet tall) and use metal T-posts in the middle of each row with a fence nail partially hammered into it to hold moveable wires at about knee height (Figure 18A).
For best results, prune your raspberry plant three times per year. In spring, cut the fruiting laterals back to 8 to 10 inches from their base and trim out any damaged or dead canes. Then, in summer, prune the floricanes to 6 to 12 inches after they finish producing fruit. Finally, in the fall, prune out any dying or dead floricanes from the previous season (caning out). By doing this you will encourage a second crop on the primocanes.
Yellow Raspberries
Raspberries are a staple in the vegetable garden, adding sweetness and color to salads, fruit dishes, baked goods and more. They’re also nutritious, providing vitamins B and C, folic acid, copper, magnesium, iron, potassium and cancer-fighting ellagic acid. Breeders have developed a wide variety of cultivars, with fruit colors from very light to dark yellow and orange hues. Some varieties are everbearing, producing two crops each year. Others, such as Anne and Goldie, produce only one summer crop.
Most raspberries grow best in full sun. Avoid planting in areas that receive afternoon shade or windy locations, which can result in poor berry production and damage to the plant’s limbs and fruit. Because the canes are perennial, choose a planting site that is well-drained and not subject to winter waterlogging. Raspberries grow in deep, loose, moisture-retentive soil with a slightly acidic pH (6.5 to 6.7). The soil should be rich in organic matter, such as compost or aged manure, but not sandy or clayey types.
Plant bare-root or potted plants as soon as the ground can be worked in spring. Plantings should be spaced 1.8m (6ft) apart and rows 12 to 18 inches apart. After planting, mulch the area with a layer of 7.5cm (3in) of garden compost or other organic material to conserve moisture and improve soil condition.
Prune new growth of summer-fruiting raspberries as soon as it develops in spring to keep the number of fruiting canes low. Remove all suckers that form in the row, and prune out old canes that have stopped producing fruit. Everbearing varieties, on the other hand, can be left to grow and fruit freely as long as they are not crowded by new growth of floricanes in late summer.
For maximum yield, keep the fruiting area free from weeds and other competing vegetation. Raspberries are prone to the fungal disease verticillium wilt, which can kill young or weak canes and cause the plant to defoliate during the growing season. To control this disease, practice good row maintenance and select resistant varieties when you’re replanting.
Black Raspberries
Black raspberries (Rubensia x laciniata) grow on long, arching canes that root from the tips. Like other bramble fruits, they attract a wide range of wildlife that uses the plants for shelter and food. Their prickly berries are a favorite of deer, pigs, and rabbits. The animals poop out the still-viable seeds, which spread the plant’s genes across new areas far from the parent plant colony. These offspring bushes then germinate and grow into full-fledged raspberry colonies. This process of natural dispersal helps to maintain genetic diversity in the berry.
In the garden, black raspberries grow well in full sun. They tolerate shade but are less productive in it. They grow best in sandy loam soils with good drainage, but they can also thrive in clay soils that are amended with lots of organic matter and well-rotted compost. They are tolerant of drought, but they will produce better in moist soils.
Like other caneberries, black raspberries are a delicious addition to fruit bowls, smoothies, salads, cobblers, and pie. They are sweeter than other types of raspberries and have earthy, woody flavor notes that make them a nice complement to nuts, cheeses, and chocolate in baked goods.
Although they’re both tasty, there are some important differences between blackberries and black raspberries. The most significant difference is that black raspberries have a hollow center, while blackberries retain their solid, round shape once they’re picked. Black raspberries are also a bit more perishable than blackberries, though this is partly due to their hollow cores.
Black raspberry plants are easy to propagate by taking cuttings from established bushes or purchasing cultivars. However, they are notoriously difficult to germinate from seed and must be treated with gibberellic acid and potassium nitrate. Many anecdotes indicate that a double dormancy is required and scarification is recommended for successful germination.
Because of the challenging germination rates, black raspberries are rarely grown commercially. However, they are popular with home gardeners who appreciate their sweetness, low calorie content, and nutritional value. They are also a staple in many wild foods, as they are widely found throughout the United States and parts of Canada.
White Raspberries
Raspberry plants are very adaptable and grow well in many soil types, but they thrive in sandy loam with a pH of 5.8 to 6.5. The soil should be well-drained and nutrient rich. Have the soil tested before planting, and add lime or sulfur to raise or lower the pH as needed for optimal plant health and production.
Raspberries can be grown from dormant bare-root plants, which should be planted in early spring, or as potted plants. Both are often available as certified disease-free stock from local nurseries and garden centers. It’s important to purchase only healthy stock, as raspberries are susceptible to a number of diseases and insects.
If the soil in your garden isn’t suitable for raspberry growth (even after making all possible amendments), you can plant a raised bed or container of raspberries. Both everbearing red and yellow raspberries can be grown this way, but the best option is to plant the ever-bearing “blackcap” cultivars. These can be grown either in a deep pot or in a large raised bed. They require no winter covering, and can be harvested all summer long.
A trellis is required to support the raspberry canes and protect them from wind damage and ground rot. The best trellis system is made from wire, although twine can also be used. When using wire, you will need earth anchors and gripples or strainers to hold the wire securely.
In addition to trellising, it’s important to use drip irrigation for all raspberry plantings. This reduces weeding, conserves water and helps control diseases that may be spread by wet leaves.
The fruit of raspberry plants consists of sections or drupelets that enclose the seeds. Unlike blackberries, raspberry fruits are not hollow inside. This difference allows you to easily see if the raspberry is ripe.
Raspberry plants are usually pruned twice each year to maintain their vigor and productivity. The first pruning takes place in the spring, and consists of removing weak canes and cutting back tall canes to 4.5 to 5 feet. The second pruning occurs after harvest, and consists of removing the canes that bore fruit.
