Raspberries

Can raspberries be successfully grown in North Dakota?

Yes, they are one of the most reliable fruits for growth in this area.

What type and variety of raspberry would be best for this area?

The red raspberries are hardier and more adapted to our area than black or purple varieties. My favorite variety is Boyne. It was introduced from Canada, is very hardy and vigorous. I have grown Royalty which is a purple variety. It produces more fruit than Boyne but the berry quality is not as good.

When can raspberries be planted?

They can be set out in early spring once the soil is warm enough to be worked. Raspberries can be planted in either a hill or row system. Plants in a hill system can be cultivated between in both directions. In a row system, plants should be planted 3-4 feet apart in the row. The rows should be 5-6 feet apart to allow for the row to widen out.

When and how should raspberries be pruned?

Canes should be thinned in the spring of the year. They should be about 6 inches apart or 8-10 canes per 2 feet of row. In the hill system, select 6-10 vigorous canes and remove all others. Keep the largest canes which will be the most productive. After thinning, cut 6" off the tips of the remaining plants; this will cause them to branch out. After the two year old canes have finished bearing fruit, they should be removed at ground level.

Spider Mites

What type of damage do spider mites cause plants?

Spider mites are tiny plant pests which suck sap from plant leaves. They multiply rapidly and can even kill large plants if not controlled.

Which fruits can get infected with mites?

Almost any plant can have mites, but raspberries can be severly infested.

How can we tell when plants have mites?

Spider mite infestations can be detected by holding a piece of white paper under a suspected leaf. Tap the leaf lightly. If mites are present they'll fall onto the paper and appear as tiny crawling specks.

How can they be controlled?

Mites can be controlled by applying an insect such as malathion or kelthane or by physically washing them from the plants with a strong spray of water. Treatment must be repeated weekly for at least 3 weeks.

Strawberries

When can strawberry plants be set out?

They are usually best planted in early spring, but may also be planted in late summer if we have enough moisture to get them established before winter.

What varieties would you recommend?

Several Junebearing varieties such as Redcoat, Kent, Sparkle, Dunlap and Trumpeter are good. The main everbearing variety for our area is Ogallala.

Which type of strawberry would be the best?

It depends on how often and when you want to harvest the fruit. The commercial growers plant Junebearers because they want only one large crop per season. Everbearing varieties will produce at least 2 smaller crops during the year.

What type of location is best for strawberries?

They need a well drained loamy soil but will do well in our area. They also need full or nearly full sun, a little extra water and fertilizing during the growing season.

Protecting Strawberries For Winter

Do strawberries need any kind of special protection for winter?

Yes, they need at least 4" of covering for the winter. Straw or hay works better than leaves or grass clippings which tend to mat down badly when wet.

When should they be covered?

It's best to wait until the ground is frozen and the plants are dormant.

Why do they need to be covered?

The flower buds for next years strawberries are already set on the plants. Exposure of these buds to extremely low temperature can damage these buds and reduce next years crop. Alternate freezing and thawing of the soil next spring will damage the plant roots.

How do we know when to uncover the plants in the spring?

Generally, we don't remove the mulch until the plants start to grow in the spring.

Slugs

What can be done to keep the slugs under control?

Since they are not an insect the normal chemicals such as malathion won't work on them. There are several baits available which work well. Bug-geta liquid snail and slug killer is commonly available and does a good job. It gives off an odor which attracts the slugs. They eat it and proceed to die.

Can they be controlled without using a chemical?

Yes, but it's very difficult. Beer, put out in a partial buried pie tin just before dark, works as a good natural bait for slugs.

Which plants do the slugs feed on?

They really don't seem to be too particular about what they eat, but can really be a problem ripening strawberries.

How do slugs overwinter?

They overwinter in the soil or under litter and debris. Cleaning up the garden in the fall will reduce the overwintering population.

Yellowing of Plant Leaves

What causes the plant leaves to turn yellow?

Usually the yellowing of plant leaves is caused by the inability of the plant to take up enough iron from the soil to keep the leaves green. This condition is worse when we have a lot of rain or water heavily.

What is this yellowing called and what symptoms should we look for on the plants?

We call this condition iron chlorosis. A sure fire method of distinguishing this condition from other problems is to examine the affected leaves closely. With iron chlorosis the leaves will be yellow but the veins in the leaves will be a greener color.

What can be done to treat iron chlorosis?

Iron supplements are available in both the liquid and powdered form. The liquid form when mixed with water works good on low growing plants and shrubs but has short term results. The powder which needs to be gotten down to the roots is slower acting but has longer term results.

This page was last updated August 2002

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