Learn About Raspberries

Posted in: Raspberries
Learn About Raspberries

How To Sow    How To Grow    Tips    Common Pests    FAQ

How to Plant

  • Raspberries may be planted as bare root or potted plants.
  • Choose a well-drained, sunny location with no standing water. Prepare the soil before planting by mixing compost or other organic matter in with the soil. Work the soil deeply.
  • Space canes 3 feet apart in rows 6 feet apart. Dig each hole to twice the size of the root mass.
  • Plant black and purple varieties 100 feet away from red and yellow varieties.

Planting Bare Root Plants:

  • Before planting, trim very long or broken roots.
  • Cut back top growth to 6 inches.
  • Set roots 1-3 inches deeper than formerly grown.
  • Back fill with loose soil. Gently press soil in around the root ball. Transplants need good root-to-soil contact. Do not press too hard because that can cause soil compaction and root damage.
  • Gently water around the root ball to settle the soil and drive out air pockets.
  • After planting be sure to mark the plants with plant labels so you know where they are and what varieties they are.
  • Mulch with 2-3 inches of compost of pine needles to retain moisture and prohibit weed growth.

Planting Potted Plants:

  • Set the plant in the hole at the same depth as it was growing in the pot.
  • Backfill the hole and press firmly around the base of the planting.
  • Water deeply. The water will seal off any air pockets around the root ball.
  • After planting be sure to mark the plants with plant labels so you know where they are and what varieties they are.
  • Mulch with 2-3 inches of compost of pine needles to retain moisture and prohibit weed growth.

How to Grow

  • Keep weeds under control during the growing season. Weeds compete with plants for water, space and nutrients. Control them by either cultivating often or use a mulch to prevent their seeds from germinating.
  • Add mulch each year as needed.
  • Keep plants well-watered during the growing season, especially during dry spells. Plants need about 1-2" of rain per week during the growing season. It's best to water with a drip or trickle system that delivers water at low pressure at the soil level. If you water with overhead sprinklers, water early in the day so the foliage has time to dry off before evening, to minimize disease problems. Keep the soil moist but not saturated.
  • In the spring, before leaves sprout, apply a granular fertilizer following the instructions on the label. Most new growth will come from the plant’s crown under the soil. Plants use a lot of energy in spring when growth begins, so do not let plants dry out.
  • Remove all wild brambles near cultivated varieties to prevent virus diseases.
  • Pruning Standard Raspberries:
    • Do not prune the first year EXCEPT to remove dead, damaged or diseased wood.
    • Each spring select 5 or 6 of the most vigorous new canes and cut them back to 30 inches tall. All other canes can be removed.
    • Remove and destroy canes immediately after they fruit in their second summer. They will not bear again.
    • Add a summer topping to encourage side shoots off the canes to the pruning done in early spring and after harvest. Pinch back 3-4 inches off shoots up to 24 inches tall.
  • Pruning Everbearing Raspberries:
    • Do not prune the first year EXCEPT to remove dead, damaged or diseased wood.
    • Each spring select 5 or 6 of the most vigorous new canes and cut them back to 30 inches tall. All other NEW canes can be removed.
    • Do not remove last year’s fruiting canes- they will fruit again in early summer. Pinch back 3-4 inches off their lateral branches.
    • Expect new canes to fruit in the fall of their first year and in early summer of their second year.
    • Remove and destroy old canes immediately after their second fruit in early summer of their second year. They will not bear again.
  • Monitor for Pests and diseases. Check with your local Cooperative Extension Service for pest controls recommended for your area.
  • Cane fruits may need support to help prevent against wind damage and make for easier harvest. Tie canes to wire that is strung parallel between two posts at either end of the row.

Harvest and Preserving Tips

  • Raspberries ripen on the plant at different times through the season in summer. Berries ripen quickly and are highly perishable. Pick frequently and discard berries that have rotted on the canes to prevent diseases.
  • Hold the berry carefully between your thumb and forefinger and pull. Berries are ripe when they are easily pulled from the core without getting squashed. At their ripest and sweetest, berries are plump and turn the deepest color, depending on the color of the variety.
  • Expect to harvest at least twice a week.
  • Keep berries in a shallow container, around 3 berries deep. Quickly cool berries in a refrigerator after picking. Properly stored, berries can keep for 3-7 days
  • Raspberries may be frozen or used for preserves.

Common Disease Problems

Botrytis Fruit Rot: Flattened, black masses of fungus appear on canes. Open flowers can become infected which in turn infect the berries. Berries become mummified. Burpee Recommends: Prune to improve air circulation. Allow fruit to ripen in an open canopy by pruning accordingly. Remove mummified fruit as the disease overwinters in the berries.

Crown Gall: Rough, wart-like growths or galls appear on the crown at or just below the soil surface. These can also form on the stems or canes of blackberries. Plants can become stunted, subject to drought stress and wind damage. Large enough galls may cause girdling which results in plant death. Burpee Recommends: Examine the canes prior to planting for any indication of galls. Avoid injury of the plant. You can remove the gall if it is small enough by cutting around it into healthy wood allowing that area to dry out, cutting into healthy tissue as little as possible. If plant is severely infected, remove it.

Orange Rust: This fungus causes plants to become stunted and weak with poor fruit production. Shortly after new growth appears in spring new shoots are weak and spindly, leaves are pale green to yellow. In a few weeks lower leaf surfaces are covered in bright orange powdery spores. Affected leaves wither and die by early summer. The disease is systemic, and remains throughout the plant so just removing infected leaves will not improve the health of the plant. Burpee Recommends: Dig up and remove infected plants and destroy nearby wild brambles. Remove plants before the spores are discharged if possible.

Phytophthora Root Rot: This soil borne disease thrives in poorly drained soils and can live in the soil for years. Above ground symptoms include pale or reddish leaves, small leaves, defoliation, branch die back, stunting and death. Burpee Recommends: Remove infected plants.

Raspberry Leaf Spot: This causes small spots to appear on the young foliage. As the spots grow the tissue may fall out leaving holes in the leaves. Eventually the leaves will drop and weaken the plant. The disease is worse when it occurs on the primocanes as the fruiting canes will die back after producing fruit anyway. Burpee Recommends: Remove affected plant debris. Provide good air circulation through pruning and removing canes that have fruited.

Common Pest and Cultural Problems

Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.

Discolored Foliage: Brown foliage can result from drought stress, particularly in mid-summer. Burpee Recommends: Water regularly and use mulch to conserve water and control weeds.

Raspberry Cane Maggot: Larvae are white and legless and turn into small flies as adults. A plant affected by the maggot wilt and become discolored. Swelling in stems may occur. Burpee Recommends: Prune and destroy infested canes. Keep plants well watered to improve plant vigor.

Raspberry Crown Borer: Larvae have white bodies with brown heads. Adults are clear-winged moths with yellow and black banding. When attacked by the borer, plants will lack vigor and will be stunted. Wilting occurs in lateral cane growth. You can cut open the stems and see the tunnels the borers make. Burpee Recommends: Prune and destroy infected canes to prevent spreading. Ensure plant is not under stress as pests are attracted to plants that are weak.

Root Weevils: Adults are flightless, dull brown or gray. Adults feed on the foliage while the larvae feed on roots destroying root hairs and chewing their way through the bark and cortex of larger roots. They can tunnel through to the crown. Burpee Recommends: Check roots for larvae prior to planting. Contact your Cooperative Extension Service for control assistance.

 

FAQ

Do I need two different varieties to get fruit?  No, raspberries are self-fruitful.

Will I get fruit this year?  No. Expect fruit one year after planting and 3-5 years after planting for full fruit.

Are there any raspberries for zone 10? Sorry, raspberries grow best in cool climates and are not recommended in zones warmer than 8.

Can I grow raspberries in containers? Raspberries are rangy plants on the large side, usually 4-8 feet in height and are challenging to grow in containers. 

How far from blackberries, black raspberries and wild brambles should I plant my red raspberries?  Plant at least 100 feet apart to avoid disease issues.

May 10, 2021
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