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Ron Smith answers questions about flowers, trees, gardens and shrubs.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I work at an outdoor stand that sells German glazed roasted nuts and sarsaparilla. That means we are surrounded by bees of all kinds. We have been using bee traps and a shop vacuum to collect them, but we really hate to kill them. While reading one of your articles, you mentioned something about companies that buy bees for their venom. Can you send me some contact information for the companies? (e-mail reference)

A: I'm sorry that this particular information is still on the website. I get requests for this information about once a year or so. The yellow jackets are not collected for this purpose anymore because a synthetic form has been developed that is more economical. People who professionally remove these beasts do so for a cost, which I don't have figures for. You are very likely dealing with yellow jacket wasps. Don't try to be nice to them because they will not return the favor. Get them trapped or vacuumed up and killed as quickly as possible. An old trick was to have a separate source of food, such as a pile of cornless corn cobs still warm and dripping butter in a plate away from the stand. They will swarm there for you to vacuum up if you are brave enough. Killing the wasps by freezing is one of the quickest ways and doesn't involve you handling any poisons. Just place the sealed vacuum bag in the freezer overnight and that will be the end. Usually true bees are not involved in lurking around food stands to any extent. They are after flower nectar and pollen. Sorry I couldn't assist you on this.

Q: I have a few blue spruce trees that were burned by muffler exhaust as we were doing some excavating. Will they come back or should the branches be cut or trimmed off? What are other options? If you think the trees will come back, I’ll just wait until spring to do anything. If they’re still brown next spring, are they more than likely gone and should be removed? (e-mail reference)

A: The other option would be to wait to see if anything that has been burned will recover. It may be superficial, so the trees will make a good recovery if given enough time. If waiting until spring isn't acceptable because of the visible damage to the trees, then go ahead and prune them off now. You can check under the bark tissue to see if the cambium is still green. If so, it is fairly certain the trees will recover but probably not until next year. A good clue would be if the buds are starting to swell and are greening up. If the buds are toasted now, they will not regreen by next spring. Grab some buds to see if they crumble between your fingers. If so, then go ahead and prune now.

Q: Many thanks for your website. I have an old grapevine that is doing well. However, there is a single vine gowning on a horizontal arbor that has not done well the past few years. You mentioned using a Bordeaux or lime sulfur mix. I think what was missing was the ratio of the mix. I guess you are mixing the products with water. I would appreciate any help on this. Thanks again for all the information. (e-mail reference)

A: Be warned that copper-based fungicides that include a Bordeaux mixture are toxic to some grape varieties, such as the Concord. A Bordeaux mixture only should be applied while the plant is leafless or dormant. Although there are many formulas for preparing a Bordeaux mixture, a ratio of 10-10-100 works well for many disease-causing pathogens. The three hyphenated numbers represent the amount of each material to add. The first number refers to pounds of copper sulfate, the second to pounds of dry hydrated lime and the third to the total gallons of water. Thus a 10-10-100 Bordeaux mixture would contain 10 pounds of copper sulfate, 10 pounds of lime and 100 gallons of water. A more manageable amount for the home gardener would be a gallon mixture of 10-10-100, which would be 3 1/3 tablespoons of copper sulfate and 10 tablespoons of dry hydrated lime in a gallon of water. You can purchase copper sulfate and hydrated lime at most garden centers. Apply the Bordeaux the same day you prepare it. After you have used up the mixture, immediately rinse the equipment at least three times because the mixture is highly corrosive to metal tanks and pump parts. Add a small amount of vinegar to the rinse water to neutralize any leftover residue. When applying Bordeaux, be sure to wear protective clothing and goggles because the spray deposit is corrosive. It can stain clothing permanently and is difficult to wash off. Your vine likely would benefit from an annual spring pruning sometime in early or mid-March to keep it under control and possibly increase fruit production. It also would help reduce disease problems. You might want to tap into the Penn State University Extension Service to see if it has any material on pruning grapevines. Go to to find someone near you who can assist with this. Thanks for the nice comments about the website.

Q: I live in northeastern Illinois and have a pin oak approximately 15 to 20 years old. This year, the leaves turned brown and curled up in August, which has happened before. There is another tree down the block that is beautiful and dark green. Our tree is always light green. How should we treat this? I read it may be iron deficient. Thank you for your help. (e-mail reference)

A: You may have read correctly. Pin oaks manifest iron chlorosis in alkaline (high pH) soils that are common in the upper Midwest. However, you need to contact someone with the Illinois Extension Service to get this analyzed because there may be other issues with this tree that should be addressed. Go to to make contact with a local agent. The agent or specialist should be able to assist you.

Q: I have a large jade plant that I grew from a small cutting. I lived in Illinois for a long time and it lived indoors in a north-facing window. It did very well. I moved the plant to Virginia with me in February. I had my fears about moving it, but it did not seem to exhibit any bad effects. It was indoors in a west-facing window for about three months with the shade pulled. In May, we moved to a house in Virginia. The jade was outdoors for a week or two before I got it back inside. It is in a corner where it gets sunlight from the east in the mornings and then indirect light throughout the rest of the day. It also is near the air conditioner floor register. In the last few weeks, small to medium outer branches and quite a few leaves have been falling off. I have been puzzled because I don't see any signs of wrinkled branches, which I look for as a sign of overwatering. I don't see any signs of bugs, mold, fungus or other diseases. There is new growth on other branches. However, the size and frequency of the branches falling off is alarming me. I water the plant about once a week, although I see you recommend less often. It never seemed to be bothered by the watering schedule. Are the dropping branches because of overwatering? Thanks for your help. (e-mail reference)

A: Most likely, the dropping branches and leaves are the result of drafts from the floor register. See if you can direct the air flow away from the plant. Keep in mind that this is a tropical plant that is intolerant of anything approaching cool air. Most would be surprised at the temperature of the air coming directly out of the register vents. Place a thermometer there sometime while the air conditioner is running. If that isn't the problem, then I have no other suggestions for consideration.

Q: I've recently discovered your wonderful website! Thank you so much for all the questions answered without having to ask. One thing I am still wondering about is my carrots. They have tiny, skinny, black- headed worms that are clear, white or yellow. My husband will eat just about anything but for some reason has drawn the line at worms in the carrots. Is there some way to get rid of the worms before planting next season? Our growing period is very short, so I don't have a lot of time between the last frost and seeds going in the ground. Can I do something this year? (Canada)

A: These worms are carrot maggots or grubs. Identifying what they are is not important at this stage. Be a fanatic about cleaning up this fall. Leave no part of a carrot behind. In fact, turn the soil over once you've pulled everything to expose those worms that are trying to hide from Canada's winter. Plant your carrots in a different location next year if possible. This will help in disrupting the life cycle of the worms. Work in an approved soil insecticide for grub or soil maggot control just prior to planting next spring. Be sure to follow the directions on the label. This combination of actions should do the trick so that you can enjoy a healthy carrot crop next year.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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