Questions on: Raspberries

Ron Smith, Horticulturist, NDSU Extension Service


Q: We have a large batch of raspberry bushes. When is the best time to prune them and how far back? This is a second year we’ve had the raspberries, so we hope to get some berries this year. (Gering, Neb.)

A: Now is the best time to prune. Prune them back to about breast height. Thin out to the base of the plant anything that is spindly. Do something to support them or else they will be pulled over by the spring growth. If you do that, berries should set for you.


Q: I know that fall is not the preferred time to transplant raspberries, but we have a property for sale with an excellent raspberry patch. I am going to try to transplant some of the plants to our new home before the sale is final. Do you have any suggestions on transplanting at this time that might increase their odds of survival? (Fargo, N.D.)

A: Go ahead and dig them out as best you can. Replant them right away and water them in. Raspberries are almost like weeds and will grow even if mishandled.


Q: I have a small raspberry patch that has developed mold on the raspberries. Can this be treated and how? (e-mail reference)

A: Your problem is probably mildew. At this point, it is too late to do anything about it. Next year, put down a preventative spray as the flower blossoms drop off.


Q: I planted six red latham and six heritage raspberry plants. They started to get leaves and some were getting suckers. One had six buds on it. Now the leaves are turning brown and wilting. Some of the canes are now sticks. I did have some foliage get eaten off some of the plants, but they have started to grow leaves again. Are the plants that are wilting diseased or planted too close to trees? Will the plants come back or do I need to replant? Do rabbits or birds eat raspberry plant foliage? (Cavour, S.D.)

A: Raspberries need full sun. The rabbits will girdle the stems during the winter months unless you protect them. Squirrels will nibble on anything they can, but this is the first I have heard of this happening with raspberry plants. If you planted them in a former site that had other ornamentals, flowers or vegetables in it, your berries could be slowly dying from verticillium wilt, which is a soil-borne fungus. Deter varmints from feeding with pepper spray, Liquid Fence or Hinder.


Q: I bought a house with a raspberry patch on the south side of the garage. According to your article, just about everything is wrong with the patch. The patch has very tall canes leaning on the garage wall. The first year, I cut the canes down to about 6 inches, but now they’ve grown very tall again. I see that I should have cut them down to about 4 feet in early spring. It probably is too late to do that now. The real reason I am writing is that small sprigs are springing up all over my lawn in the vicinity of the raspberry plants. Is there anything I can do about this? Any further advice on the care of these plants would be appreciated. (Kindred, N.D.)

A: You can cut the sprigs out with a spade or spot spray them with Roundup. Try to avoid overspray or drift. The best approach is to dig a trench around the raspberry patch, assuming you want to keep them for their fruit production, and place a root barrier (BioBarrier) around them to keep them in check. From my experience, you need to go down 8 inches or more.


Q: We bought our new house three years ago and planted raspberry plants. On the other side of the fence are four spruce trees belonging to our neighbor. I've heard of a raspberry fungus that can affect pine or evergreen trees. Now I'm worried that I need to dig up the raspberry bushes to not pose a threat to our neighbor’s trees. What should we do? We can live without the bushes and I'd feel awful if our neighbor's beautiful spruce trees died due to fungus. (e-mail reference)

A: Don't worry. Spruce trees are capable of defending against anything that raspberries can catch as far as fungus or other pathogens. While there are some common maladies that can affect broad populations of plant species, they are not common. The pathogen that will attack spruce usually will not attack raspberries because they are two different plant families. Enjoy your berries and your neighbor's spruce!


Q: I have a raspberry patch that came across the fence years ago from my neighbor. The patch used to produce lots of berries, but we've had water restrictions the last three years that hampered development, but the restrictions have ended. I used to cut the patch back in the fall, but was told not to. Now I don't know what is right. I do not know the variety. Do I cut the patch back in the fall? Since I didn't last fall, can I do it now? What fertilizer should I be using? Is there a way, except pulling, to get rid of the bindweed that has come? (e-mail reference)

A: Raspberry plants produce biennial canes, which means that the first year they are vegetative only and don't produce fruit. The second year, they flower and produce fruit, but then die. The plants that fruited for you last year can be removed because they are dead anyway. Those that were vegetative last year will or should produce fruit this season. It is best to get the old canes removed as soon as possible. Most people get around to it in the fall after a couple of hard frosts. Carefully spraying the bindweed with Roundup eventually will take it out. The operative word is "carefully" because the Roundup also could take out the raspberries. A 5-10-5 or 10-10-10 fertilizer applied as new growth starts showing is all that is needed.


Q: I just purchased some wooded land and would like to get a raspberry patch going. A friend has some on his property and offered to give me some. Can I cut slips or do I need to dig up entire plants? (e-mail reference)

A: You can go either way. Generally, it is a better idea to dig up suckers from around the base of healthy plants. With raspberries and strawberries, viruses are transmitted through insect feeding activity, which often results in a gradual decline of fruit productivity. Digging the new sucker growth is a way of getting ahead of the virus migration in the plant, which could exist in the older cane cuttings that also could be used for transplanting.


Q: Someone stopped in who has a couple of rows of raspberries that he moved to a new location a few years ago. Before the move, the raspberries produced fruit, but not now. He says there has been very good vegetative growth, just no fruit. Any thoughts? Also, what would be your choices for some varieties of shrubs/bushes to be placed in a nonwatered location and wouldn’t exceed 3 feet in height when mature? (e-mail reference)

A: The raspberries could be producing their vegetative canes this year and will bear fruit next season. Remember, the raspberry is a biennial cane that is vegetative the first year, bears fruit the next, but then dies at the end of that year. Shrubs that wouldn’t exceed 3 feet are potentilla, snowmound spirea, Annabelle hydrangea, dwarf or Arnold honeysuckle, hibiscus, redleaf barberry and compact European cranberry bush viburnum. Not a complete list by any means, but about all I can think of right now.


Q: I have raspberry canes that suddenly started wilting and dying. There are healthy canes among the dead ones. I could not find borers or girdlers, but did find many brown, rotting roots. Could this be rhizoctonia? The planting is at least five years old. Any suggestions on how to rejuvenate the canes? (e-mail reference)

A: Get the rejuvenation started early next spring. If they are dug and separated now, the loss would be heavy. Next spring, as they are about to break dormancy, would be best because the canes would have the vigor to be re-established.


Q: About four years ago, a friend gave me some raspberry shoots. Every summer I have great little leafy raspberry bushes, but no canes or fruit. Can you tell me why? I suspect too much or too little of something, such as potassium, calcium or alkali. I have not been fertilizing the plants. Thanks for whatever help you can provide. (Mansfield, S.D.)

A: The raspberry is a biennial cane, which means it is vegetative the first year and bears flowers and fruits the second year. Don’t cut these back because they will be the ones producing for you next year. If for some reason you have not been pruning them back, then you may have a cultivar that is not hardy for your area, so you should get it replaced. For more information on raspberry culture, go to www.ext.nodak.edu/extnews/hortiscope/fruitveg/rspberry.htm.


Q: We just moved into a house that has blueberry and raspberry bushes. When is a good time to transplant the raspberry bushes? They are in the middle of a patch that we need to rototill. How should I move them? Is it safe to transplant them close to a building? Can I plant the raspberry and blueberry bushes together? How long before the blueberry bushes provide fruit? What is the best way to maintain these bushes? (e-mail reference)

A: Don’t worry about your raspberry bushes that are in the way. Dig up the bushes and, if you want to try now, replant them where you want, but they likely will die at this time of year. Raspberries are very generous at multiplying. In the spring before they leaf out, dig up a crown and divide it and then plant where you want. Always cut back the canes that bore fruit the previous year. Cut the canes to the ground, if it wasn’t done the fall before. It’s a bad idea to mix the two species of plants because they have different requirements and growth habits. Blueberries require soil acidification on a regular basis with aluminum sulfate and lots of sphagnum peat moss. It wouldn’t hurt the raspberries, but I’m afraid that they would simply take advantage of the extra care and grow like Jack’s beanstalk! They are challenging enough to control without giving them extra encouragement.


Q: We had two raspberry plants in our small backyard. We decided to remove them and replant with strawberries. Now we have multiple raspberry runners coming up all over the place. We are using Roundup to control the spread. Is there any way to kill all the raspberries or do we have to write off this growing season and use a soil sterilizer? (e-mail reference)

A: You have been hit with “raspberry surprise”! These plants actually are weeds, but we have fallen in love with their fruit, so control them like weeds. The persistent application of Roundup to the foliage and digging out of any little sprouts eventually will do the job! Hang in there.


Q: What would be the proper weed killer to use on weeds that are overwhelming a raspberry patch? (e-mail reference)

A: To control a weed, one needs to know what it is. Grassy weeds can be controlled with Vantage, while broadleaf weeds are a little more difficult and the control needs greater care in application. Look at the labels for Roundup, Devrinol, Princep and Simazine. All are labeled for weed control in raspberries, but have limitations as to the timing. In raspberries and strawberries, you are better off taking control of weeds using mechanical means, which is good, old-fashioned hoeing!


Q: I hope you can help me. We want to plant some raspberries, but I have been told that raspberry bushes like to spread through their root system. Is that correct? What’s the best way to control it? (e-mail reference)

A: It is true. To keep the bushes from spreading, cut them out as they spread and replant somewhere else if you want them or simply destroy the spreaders. It is a little extra work, but worth it and is something the average person can keep up with if you don’t have too many raspberries!


Q: I recently moved into a new house and want to get rid of the raspberry bushes. I want to give a few to friends, but I am not sure if they are diseased. How can I tell if they are diseased or worth transplanting? (e-mail reference)

A: Only a lab analysis can make that determination. Give away only the youngest, most vigorous growing shoots. There’s a good chance those plants will be disease-free.


Q: I don’t know what the problem is with my raspberries. I don’t know what plant type it is. They grow quite well and have a constant bunch of sucker plants, but, if they bloom, the blossoms dry up and bare no fruit. I transplanted some of the suckers last year to get a larger patch. They are doing well, but still no berries. The garden area is a former bean and corn field, which I farmed for 30 years. Where am I going wrong? (Tea, S.D.)

A: It sounds like they might have a virus or it could be the cultivar (variety) you selected isn’t suited for bearing fruit at your location. I would suggest getting rid of the plants and planting something that is more locally adapted. Usually raspberries produce abundant fruit for several years before a virus causes a decline in quantity and quality.


Q: I have a question about the raspberry patch I have. The patch is basically in a large square and is so thick I was considering transplanting them into more defined rows. Weed control would be easier and we could gather fruit from all the plants. Should I transplant before I kill the weeds or after? When should I do the transplant? (e-mail reference)

A: I would suggest mowing over the plants and then digging out the new growth as it emerges next spring. I am all for accomplishing tasks the easiest and most effective way possible.


Q: I want to start a raspberry patch. A neighbor’s mother has some she’ll give me, but when’s the best time to plant? Do they have to be in full sun or can they be in part shade (mostly sun)? Also, my husband has his heart set on having a cherry tree. He wants the good eating variety, not the baking variety. I’ve been searching the internet for a self-pollinating sweet cherry for our area and have only found a couple, lapin and Stella. Are either of these really as sweet as they claim and will they do well in our area? (Lisbon, N.D.)

A: Raspberries are best transplanted in early spring. The more sun they receive, the better they will produce. They will produce well enough, for most people, in partial shade as long as you are not attempting to make a living from them. I don’t know about lapin and Stella cherries because I’ve never heard of them, but take a chance and give them a try. Most companies are pretty straight with their promotional literature because they want repeat business.


Q: I would like to expand and reorganize my raspberry patch. I have seen raspberries growing in about two-foot diameter clusters, but I can't find any information on growing them this way. What is the best spacing and what is the best way to bind the canes? (Fargo, N.D.)

A: Raspberries have been grown just about every way possible. I suppose the best way is the one that suits the individual gardener. Without control on a regular basis, raspberries can become an invading, obnoxious weed! I have grown them in rows with enough space to get my small tractor through with a cultivator attached. I am currently growing a few in my backyard. The plants are supported by wire attached to stakes at the end of the rows.


Q: I have no choice but to transplant my raspberry bushes because we are building an addition where they are growing. I know from reading your Web page that this is not the best time to transplant, but I don’t have a choice. Any advice would be greatly appreciated as I am a new gardener. (e-mail reference)

A: This isn’t a good time to transplant, but raspberries are tough customers! Cut them back to short stumps about 6 inches long. Dig them out and quickly move them to the new site. Soak them with a bucket of water in which you have dissolved some Miracle-Gro. I’d be surprised if they didn’t make it.


Q: We grow several types of raspberries because we enjoy the jelly, preserves and wine we make out of them. The raspberries we have are heritage, fall gold, latham, black hawk and blackberry. How much should we prune each variety? From what I understand, heritage should be cut to the ground in winter. Fall gold should be cut to the ground to produce one large harvest versus two smaller ones. Blackberry shoots that produced in the current year should be cut.

I’m not sure what to do with the latham or black hawk. (Lesterville, S.D.)

A: You are right on the money with the heritage, fall gold and blackberry. Latham and black hawk are both summer bearing. This spring cut the canes that bore last year to the ground. Top off the growth that is going to produce this year at about four feet. Throw some 5-10-5 or something close to that around the plants and then stand back!


Q: I transplanted several raspberry plants two years ago to the northeast corner of my vegetable garden. They are growing well and look healthy. There were some berries this summer for the first time. They have re-seeded into a grouping and I am wondering if the plants should be in a row supported by a fence? What time of year is best to fertilize and transplant raspberries? (Brookings, S.D.)

A: The raspberries probably have suckered into a grouping rather than re-seeded. Left alone, the plantings will spread into a thicket that would require the cleverness of Brer Rabbit to get to the berries without getting all scratched up! They should be in rows and tied up or supported in some fashion. If you can send me your mailing address, I will forward information to you in greater detail.


Q: This is my second year of trying to establish raspberries. I have 30 plants in three rows planted 6 feet apart. The first year I watered them a great deal and was told I probably killed them by overwatering. This year I planted in the same area and all but one leafed out. They are on the north side of our property in the center of the yard and in full sun from about 10:30 to 5:30 each day. The plants leaf-out and then the leaves turn brown around the edges and die. I pulled up a dead plant and found plenty of moisture and damp soil around the roots but they snap like an old dried twig. Some of the plants actually produced a few berries this year. (Grand Forks, N.D.)

A: Sounds like the raspberries are being wiped out by a soil borne disease such as armillaria root rot or verticillium wilt. Plant in a different location and use only certified disease-free planting stock. Keep the new plantings moist but not soggy.


Q: We have a raspberry patch that came up by itself quite a few years ago under a fuel oil barrel. The barrel was moved to a new location and the plants continue to grow and spread. However, the plants do not grow berries, only a few single cells on some plants. What can we do to get berries? Do raspberries need a male and female plant to get berries? (Black Hills, S.D.)

A: Raspberries need plenty of sunlight to produce fruit. No male or female plant is involved so, if you don't over fertilize and have it in full sun, it should fruit for you.


Q: Two years ago we dug up lots of raspberry plants from our neighbor and our old patch. We put them in a new bed we created after tilling in some manure. So last year I was expecting to get some raspberries but alas, the canes died. But they were coming from the bottom so I thought we’d be patient until the following year. This year they appear to have again died. These are plants that my neighbor and I have had for years. They’ve always been hardy and have borne well for us. The old bed was getting less productive so I thought it was time to start a new bed. My neighbor came over to look and said our canes look blacker than hers. Hers are leafing out as are the ones in our old bed. Do you have any thoughts on why they would be dying? Also, should I leave them alone for another year or should I just till them up and forget it? We love raspberries and make several things like jam, wine and vinegar. It’s disappointing to have a continuing failure like we’ve had especially with a plant that is rumored to grow like a weed! (E-mail reference)

A: Most likely the problem is the manure you brought in. You can try waiting another year to see if the plants outgrow the root fungus or begin anew somewhere else, sans the manure. I am with you on raspberries! Fresh, frozen, in pies or over ice cream, they are great and good for you.


Q: My mother has a patch of raspberries about 10- by 50- feet. They have become overgrown so she would like to take out the older half of the patch. What type of spray would you recommend and should I do it this fall or next spring. (E-mail reference)

A: Spraying them with Roundup now would do a pretty good job of killing them off. You’re much better doing it in the spring.


Q: I would like some information as to when to transplant raspberry bushes. Also, they have overgrown their space. Can I prune them now without injuring the plant? (E-mail reference)

A: Transplanting is best carried out in the early spring just before new growth emerges. I would suggest pruning them after they go dormant in the fall or early next spring before new growth begins.


Q: When is a good time to transplant raspberries? Would now be a good time? (E-mail reference)

A: No, not now. Early spring before new growth breaks, or this fall when they go dormant from frosts.


Q: I have a question on transplanting raspberry plants. I have some friends who are not having very good luck with them. The plant had all kinds of green leaves when they received it. They transplanted it and then the leaves dried up after it was in the ground. It had plenty of water. What should they do? (E-mail reference)

A: What you describe to me is a pretty good indication of a dead plant. If they are strong in faith, tell them to leave it and replace it next spring if this one doesn't come back; if they are more realists and want to know now, tell them to scrape the bark at the base with either their thumbnail or knife to see if the cambium tissue is still green. If it is there is still a chance for recovery; if not, then it is history.


Q: We have had raspberry plants which were planted three years ago. They grow fine -- lots of blossoms – but they get to the berry forming stage and they just stop. It has been recommended to us to use Captan as it is probably a fungus which is stopping their growth. We bought some Captan 50% WP Fungicide but directions do not list raspberry plant treatment on the can. Please let us know when we should start using Captan and what portions we should be putting on the bushes. Also, how often should we apply it? ( Milbank, S.D.)

A: You were simply sold something without checking it out first. The label must specify use on raspberries before it can be used, otherwise it is referred to as "off-label" use and is considered illegal. Now, having said that, Captan became labeled for use on raspberries in 2000. Take the material back to the source and see if they have one labeled Captan 80WP, which should have raspberries included on the label. It may not be a disease that is causing the non-bearing problem. It could be any number of things -- environmental conditions, lack of pollinating insects, destructive insects. Who knows at this time?


Q: I have 3-year-old raspberries that barely set fruit but did not develop beyond that stage. I have just been cutting out dead stalks in the past but now one of my garden catalogs says to cut Heritage variety back to the ground each year. (Napoleon, N.D.)

A: Yes, cut Heritage back every year, right to the ground.


Q: I have a problem with grasses in my asparagus beds and my raspberry patches. I have heard that a herbicide by the name of Poast is effective in controlling this problem. Can you tell me if I can use it? (Richville, M.N.)

A: Poast is a very effective grassy weed control in raspberries. Here the basics: 1) Do not apply closer than 45 days before harvest. 2) It is effective only against actively growing grasses, with annual grasses being between 3 and 8 inches tall and quackgrass 6 to 8 inches tall at the time of application. 3) Use either a crop oil or a nonionic surfactant according to label directions.


Q: In a recent Hortiscope column you named varieties of raspberries that would grow in a cold climate and also named sources where they could be obtained. I have lost that information and wonder if you could give it again. You suggested Thunderchild, Spring Snow and Red Jewel for crabapples. Are they resistant to rust? Also, can you suggest a place to buy ornamental grasses. I've found very limited resources. (Wessington, S.D.)

A: The hardy raspberries for your area would include Boyne, Latham, Swensen, Nordic, and Royality. The crabapples I listed are resistant to rust. Some sources for ornamental grasses are:

Ambergate Gardens, 8015 Krey Ave., Waconia, MN 55387 (phone: 612-443-2248)

Bluebird Nursery, Inc., P.O. Box 460, 521 Linden Street, Clarkson, NE 68629 (phone: 402-892-3457)

Prairie Moon Nursery Route 3, Box 163, Winona, MN 55987 (phone: 507-452-1362)

That should get you started. If you get nowhere with these three let me know. There are plenty more.


Q: I have recently purchased a property in Grand Forks. One of the selling points was a tremendous raspberry bush in the back yard. The former owner said the bush yields many quarts of berries every year, but that the canes that bore fruit this last year should be pruned to keep it producing at that level. Is this correct, and if so, should they be pruned now or in the spring? (Grand Forks, N.D.)

A: The raspberry cane is a biennial one, in that it fruits on the second year's growth and dies down. So, yes, in a nutshell, the canes that bore this past summer should be cut out, as they are dead anyway and you don't want them to become vectors for transmitting diseases or insects to the new fruit bearing canes. Simply cut the old ones down to the ground and haul them out of there. It is best to do this right after the canes are finished bearing, but more often than not that chore just doesn't get done until either the fall or early the following spring. Enjoy! You are fortunate to have one of nature's most productive, tasty, and healthful temperate zone fruits in your backyard.


Q: As I was cutting down my old raspberry canes I noticed a swelling in the stems of some of the new canes. Upon further investigation I found a white larvae in the node that was about one-half inch long. Would you know what species this might be, what its life cycle is, and what actions might control this pest?

A: Most likely a raspberry cane maggot. The only control is to cut out the infested portion of the stem a few inches below the swelling and destroy.


Q: In 1998 I planted some Heritage raspberry plants. They grew very well last year but were very slow to get berries. They finally start to ripen in the middle of September. Is there any way to get them to produce the berries earlier? Should I water them on a regular basis, and what kind of fertilizer should I use? (Rothsay, Minn.)

A: It sounds like your Heritage raspberries are doing about what they should be. Water and fertilize to improve production and individual berry size. In the absence of a soil test, probably the best fertilizer to use is a side dressing of 5-10-5, at a rate of about 15 to 20 pounds per 1,000 square feet. Also, be on the lookout for cane berries and cane anthracnose, and refer to "Refreshing Raspberries for Home Grown Goodness" (H-38), a publication of the NDSU Extension Service.


Q: We have a fairly large patch of strawberries, but have been getting few berries out of this patch. What type of fertilizer should we be using and how often? Also, what should we use for weed control? We also have a large patch of raspberries along the south side of our garage and we've always gotten quite a lot from them except this year. Is it possible that this patch is dying out? It is more than 10 years old and, we have never done anything with it except to cut out the dead canes. (Barnesville, Minn.)

A: Your strawberries may very likely have a virus disease, one of the symptoms of which is a yield reduction. They and the raspberries should be fertilized twice a year; once in the spring at initial growth or green-up, and again right after harvest. The material to use is 5-10-5 at about 10 to 15 pounds per 100 square feet.

Raspberries just don't "die out" unless something is killing them. It be virus, root rot, cane cankers, anthracnose, cane borers etc.

Both crops require constant attention to good management practices to be sustained productively. For example, the old mother strawberry plant should be tilled up each year, allowing the daughter plants to be more productive. The following year, those daughters are tilled and so forth.


Q: Can you tell me what is wrong with my raspberries and when is the best time to transplant them? I also would like to know what kind of weed killer I can use to control the thistle and creeping jenny in my raspberry patch? (Napoleon, N.D.)

A: It appears that your raspberries are showing the advance stage of anthracnose. Clean up all fallen leaves and practice good sanitation by pruning out all diseased, damaged, dead or weak canes. Spray in the early spring with lime-sulfur before the leaves open up.

The best time to transplant is in the early spring when they are still dormant. Select only the healthiest crowns and reset them at the proper depth. Fertilize with 5-10-5 or something similar as the leaves open, and again right after harvest.

Controlling those two weeds is difficult. Roundup can be used perhaps most effectively this fall, when the berry canes are dormant but the weeds are still actively growing.


Q: What is the best way to keep my raspberry patch weed free? Is it okay to use Round-Up on it? (Belcourt, N.D.)

A: Weed-free raspberries is a dream that will never come true. Reduced weed pressure can be realized through proper cultivation, mulches, and the proper use of herbicides like Roundup.

Here is what I would suggest:

1. Use shallow cultivation between rows to remove weeds.

2. Spot spray carefully any emerged weeds with Roundup

3. Seed a cover crop of creeping red fescue or Covar hard fescue at a rate of 80 to 100 pounds per acre (for quicker establishment, you may want to mix in come perennial ryegrass).

4. Fertilize at a rate of 60 to 80 pounds of nitrogen (N) per acre to keep the grass healthy, and mow it three or four times a year.

5. You may want to mix in some white clover (Trifolium repens) to supply some of the N.

6. Whatever you do, maintain about 3- to 4-foot strip of weed-free soil within the raspberry row. This can be achieved with organic mulches once the emerged weeds are under control.

7. Herbicides that are registered for weed control in raspberries are Casoron 4G (grassy weeds and some broadleaf pests like Canada thistle), Poast, Princep and Suflan. Roundup of course can be used any time active growth of weeds is taking place, but spray should not be allowed to drift into raspberry foliage.

Always be sure to follow label directions, as inappropriate timing of application can wipe out a crop.


Q: I am having a problem controlling grass in my asparagus bed and also my raspberry patch. I have been told that asparagus will tolerate salt, but grass will not. Can I sprinkle salt on my asparagus bed without killing the plants? I have also been told that Poast will kill grass but is not harmful to my plants. Can I safely use this on my asparagus and raspberries? (Richville, Minn.)

A: I try to discourage the use of salt. Yes, Poast will work with both species of plants. Be sure to follow label directions.


Q: Could you send me some information about strawberries, juneberries and raspberries for northern Minnesota? (Newfolden, Minn.)

A: Refer to the following publications from the NDSU Extension Service: "Strawberries" (H16), "Refreshing Raspberries for Home-Grown Goodness" (H38) and "Juneberry" (H938). If you require anything further, please get back in touch!


Q: Is an old barnyard a good place to plant raspberries? The cattle have been gone for about 10 years. What variety should I plant, so they will be ready to pick in the fall? Is Autumn Bliss a good variety? (Fillmore, N.D.)

A: You asked the right person about raspberries! They are one of my favorite fruits, having grown a couple of acres of them in my younger days!

Here are the answers to your questions. Other information is available in a publication titled "Refreshing Raspberries for Home-Grown Goodness" (H38), produced by the NDSU Extension Service. Yes, Autumn Bliss can be grown and Black Hawk is the only hardy black-fruited variety that can be grown. Those that have grown Black Hawk swear by the good flavor of the fruit. Boyne and Latham are two of the best red-fruited ones to grow. Boyne is truly winter hardy, while Lathum needs some winter protection.


Q: Is it possible to cut raspberry bushes back in the spring before they get too tall and start blossoming? I don't want to disturb the bearing, but they keep getting too tall. (Jamestown, N.D.)

A: No problem! In fact, with my patch in upstate New York that was the standard operating procedure. Generally, I'd suggest a cutback at about 4 feet, or breast height, definately before leaf out or blooming. This will make them easier to harvest.


Q: Our raspberries produce in the spring and fall but never get big enough in the fall or in July to amount to much. Can you tell me what is wrong with our raspberries and whether we should dig them out? (Huron, S.D.)

A: Raspberries are either summer or autumn bearing. From what you said in your letter, it sounds as if yours do neither. Raspberries, like strawberries, are subject to virus infections, which among other problems, cause a decline in fruit quality and quantity.

My suggestion would be to get everything dug out and burned, and start over. Information about raspberry cultivars and culture is in the publication "Refreshing Raspberries for Home-Grown Goodness" (H-38).


Q: I have little white worms eating my raspberry plants. Can you tell me how to get rid of them? A sample is enclosed. (Velva, N.D.)

A: The sample you sent in was damaged by red-necked cane borers. Remove all affected canes and burn and spray with Sevin next spring just prior to when the blossoms open.


Q: I have two questions for you. First, why aren't our raspberries producing? They are planted in native sandy soil, with nothing added. We are wondering if we should add some black dirt and manure. Second, we are planning to put a garden on the east side of our garage. Is this a good place? There are also two small evergreens on the east edge of where the garden would be, is this bad? (Sioux Falls, S.D.)

A: Raspberries need fertile soil, so the addition you are thinking of can only improve production!

East side gardens are good in that the foliage dries sooner, cutting down on disease problems. To be productive, at least six hours of direct sunlight is needed.

Your evergreens are going to get larger, cast more shade, so I would suggest moving them.


Q: Enclosed are samples from a raspberry bush and a tomato plant. The canes with berries on them are browning and breaking down, but the rest of the canes are fine. Can you help? (Britton, S.D.)

A: Your raspberry is being attacked by a rapscallion known as the raspberry cane borer. These critters appear in the plantings in June and begin feeding on the tender cane tips, and before laying her eggs, the female punctures the stem with her mouthparts in a girdling fashion, about 6 inches from the cane tip. This is what causes the breaking off that you stated. The larvae will now burrow down the cane reaching the base by this fall, and into the crown by next summer.

To control, remove and destroy the infested portion a few inches below the wilted or darkened tip. Remove any damaged canes and crowns and burn. Spray is directed at controlling the adult beetle which is -inch long, black, with an orange thorax. Use Sevin at late prebloom or just before blossoms open.

The tomato does not appear to have any disease symptoms. The leaf curl is normal at this stage of growth and time of year. Frankly, I wish my tomato plants looked as good!


Q: Enclosed please find a part of a raspberry bush. Each year it gets fruit and then they dry up instead of developing. Please let us know what is wrong with our plants. (Litchville, N.D.)

A: Your sample showed gray mold (Botrytis) on the fruit. This is brought on by wet, rainy, humid weather before, during or right after harvest.

Since the disease overwinters in decaying foliage litter, sanitation is important in the fall. Some cane thinning or trellising may be necessary as well. Hold off on the use of fungicides unless the disease cycle repeats next year. 


Q. I have several questions concerning a patch of red raspberries that blossom but don't bear. They are an old variety I planted about 15 years ago. I have cut down the entire patch and still no raspberries. They are behind a building so I know they need to be moved out in the open. When should I transplant them, and how far apart should the   shoots be? Do I prune every year? Do I cut out the suckers and leave only one cane? When do I fertilize and is a bulb fertilizer the right kind? How deep do I plant them and   any other information you can give me would be appreciated. Maybe I should get some new plants.

Also, what should I add to my black dirt?

Thank you. (Alpena, S.D.)

A. Raspberries need a full dose of sunshine, something I suspect they are not getting, in order to set fruit. They should also be located at least 50 feet from shade trees, as the roots would compete for nutrients and water, reducing yield. Avoid planting where potatoes or tomatoes were previously grown due to the possibility of verticillium wilt infection.

Plant in early spring for best results. In your spot on the prairie, I would suggest late April. Set them so your cultivation equipment can till without damaging the plants. Application of 5-10-50 as a side dressing should be carried out right after planting. Figure 15 to 20 pounds per 1,000 square feet.

The best approach for you is to purchase new plants, as the present ones could have a virus disease that is affecting yield.

I have enclosed our extension publication H-38, "Refreshing Raspberries," to give you further information.

No need to add more soil.


Q.I would like to know how to get rid of quackgrass in my raspberry patch.

I enjoy reading your articles. (Rutland, N.D.)

A.Quackgrass in raspberry patches can be controlled with Roundup, if the canes are dormant, in late fall or early spring before new growth begins.

It can also be controlled selectively with a material known as Poast or another one called Casoron. Don't be discouraged quackgrass is difficult to control and may take a couple of applications to completely control.


Q.Enclosed please find samples of some of my raspberry plants. What is wrong with them? They appear healthy early in the season, but by now are looking sick. I have thinned and pruned them quite severely and have been spraying them for the past two years with Bravo hoping to control the problem. However, they are again showing signs of the same problem. Please advise.

Thank you for your very informative column we read in the Farm  Forum green sheet. (Big Stone, S.D.)

A.Thank you for writing and being a faithful reader of the column. The raspberry samples you sent in definitely had cane anthracnose and possibly a root rot disease. Being an old raspberry grower, I found that diseases such as these could be controlled by removing all old fruited canes immediately after harvest. The following spring, apply lime-sulfur (liquid) just as the buds are breaking.

For the possibility of root rot control, the only action you can take is to replant in a location that has better drainageand plant with a resistant cultivar such as Latham.

Be careful using fungicides after leaf-out. They may actually damage the foliage.


Q: Please advise what is wrong with our raspberry plants. We planted these in the spring of 1998, and in 1999 we had a lot of bushes, a lot of blossoms and lot of bees to pollinate but berries never formed. What did we do wrong or what should we be doing now? We have pruned them this year to only new canes. They were fertilized with 10-10-10 and watered a lot. (Milbank, S.D., e-mail)

A: I have no idea what you did wrong, as everything you said sounds OK to me. Raspberries are usually quite easy to grow productively. I would say just be patient and see what this year brings. You should get some fruit, unless the variety you selected is not hardy in your area or the blooms were killed by a late frost. If you have a fruit failure again this year, send me a small sample and I'll see if I can spot something.


Q: Last year, in the same raspberry patch, with the same light, soil, and water, about half the patch produced small, crumbly berries. The foliage looked fine. The berries tasted OK, too, but the rest of the patch had big, juicy raspberries. Is the rest of the patch going to get this, too? Should I destroy the bad part of the patch? Your suggestions or referrals are welcome. (e-mail)

A: Thanks for the good description of your problem. I had the same situation back in the good old days (?) when I was growing berries, and I had no idea what the cause was. I simply ripped the affected bushes out. Now I know--decades later--what causes your "crumbly berries." It is a viral disease known as tomato ringspot virus. The fruit is usually most obviously affected, followed by yellow rings that may show up on some of the foliage later, like this year. The disease is commonly spread by dagger nematodes but can be picked up by insects such as aphids and leaf hoppers. The best remedy is to destroy the plants so affected, and go about five or six plants beyond the ones that showed the visible symptoms to be on the safe side. I would suggest a soil sample from the base of some of the visibly affected plants to confirm the presence of the dagger nematode. If confirmed, then that area should be kept clear of all vegetation--even weeds--for two years before replanting. That is usually sufficient to starve them out.


Q: Can I use Roundup to control the raspberry shoots? I want to keep the raspberries in rows, not a bramble patch. (anonymous)

A: Roundup is translocated throughout the plant's vascular system. While the part you would be spraying is admittedly small and wouldn't likely kill the parent plant initially, continued use would eventually weaken and kill the plants. The best way to control the spread of raspberries is through annual tilling to keep them in rows.


Q: What can be used to control sowthistle and wild morning glory in my strawberry and raspberry beds? (e-mail)

A: Two tough ones! You could try to spray Roundup carefully on them, trying not to get the spray on the strawberry foliage. Since it is not soil active, it would not hurt the adjacent strawberry plants. There is nothing else I can come up with that you could use in a broadcast manner. Sorry!


Q: I have two gardening questions for you. The first one concerns the enclosed leaves from our raspberry bushes. The leaves are turning yellow and the plants seem to be drying up. The berries are small, seedy and fall apart when picked. Can you tell me why this is happening and what we should do? Next, we also raise several roses, hybrid teas and florabundas, and have been able to keep the black spot in check. This year with all the rain it has been impossible with several of them losing almost all the leaves. We spray with Ortho Rose Pride Finginex and lime sulfur spray but can’t seem to get ahead of it. Is there anything that would work better? (Enderlin, N.D.)

A: With the raspberries I suspect tarnished plant bug damage on the fruit. They are small, destructive, sap-sucking insects that feed destructively through every instar of their life cycle. They overwinter as adults in leaf/weed trash and crop residue. They feed on the flowers and developing fruit, causing deformed, "nubbins" which you describe. Practice good sanitation and early spring spraying with Sevin to control. Once roses get black spot, that is usually it for the season. Just keep spraying and collecting the infected leaves. Next spring begin a protective spray schedule as soon as the new leaves unfold.


Q: We just moved to a new house and it has raspberry and blueberry bushes. I have no experience working with either and was wondering how far back I should cut them before winter and when is the best time? (E-mail reference, Hillsboro, Ore.)

A: Both plant species should grow like weeds in your area! Raspberries have two cane types -- the primocane grows the first summer and normally remains vegetative or non-fruiting for that season. In the second summer, that same cane produces floricanes, or fruit bearing branches. Once the fruit ripens, the cane begins to senesce or die. New primocanes are produced each year, so fruit production is yearly. Once these fruit-bearing canes stop bearing, it is a good idea to remove them completely, and burn them. The longer they stay with the plant, the greater the opportunity for insect and disease problems to develop. Blueberries need only to have their weaker branches pruned. This is generally done in the early spring before the buds open. The important thing with blueberries is winter protection. Not knowing the winter extremes in your area, I suggest contacting your local extension horticulturist or other folks who have blueberries as well and see what their cultural practices are. Low pH (4.5), continuously moist soil, adequate fertility, and winter protection are the key factors in blueberry production.


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