August 29, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We have golden current bushes that are so full of berries that the branches are hanging on the ground, even after picking the berries. Is it best to leave them for now or should we prune them? Should they be pruned regularly? If so, what time of year, and what do we prune off? (Hankinson N.D.)

A: Best to not prune them now but to do it in early spring. We don't want to stimulate any new growth going into the winter months. Remove the oldest canes right back to the ground to stimulate new, vigorously producing growth.

Q: My 2-year-old spider plant is doing something I've never seen before. It seems that two leaves are stuck together as they grow and if they do split apart the tips are brown and dry (usually 2 inches of the tip or so). I use hard, room temperature water to water them with using a very mild Miracle Gro solution each watering. I haven't changed anything lately. They have been in their present location (east window) since April and were in another building, also in an east window, before that. Any ideas? (E-mail reference)

A: I can't tell you why two leaves were stuck together, but I can tell you that the brown tips are something you are going to have to live with, as it is quite common on just about every spider plant I have ever known -- including my own. It is from either the salts in the water, fluoride, or chlorine. I wouldn't continue watering with a dilute solution of Miracle-Gro each time. It isn't needed and could be contributing to the brown tip problem.

Q: One of the new trees we planted this spring is really struggling. First, all of its leaves/buds were eaten off by rabbits so we put "sleeves" around it; then the leaves/buds came back and it seemed to be taking hold when all of a sudden the top leaves turned brown and fell off. Then the lower ones started to turn brown and we noticed spider webs inside the sleeve; now its leaves look sick and have holes eaten away. Is it spiders doing that or what? (Buchanan, N.D.)

A: Being hot from working outside, I'll bet you a long, cool drink that the tree has been planted too deep. Try pulling some of the soil from around the base of the tree until you see just the top of the rootball. The spiders are your friends. They are waiting to catch any unwary insects, so let them do their work. I think if I am correct that the tree is planted too deep ( a common problem) you will see a big improvement in the tree next spring. Continue to keep it well wrapped this fall and through the winter.

Q: I was reading questions and answers on the jade plant that stated the plant could be propagated by stem or leaves, but I do not know how to do this. I also would like to know about the watering technique. My friend gave me the plant and she has had hers for years. She said she never waters the plant on top of the soil, only from the dish it sits in. But I read that water should never be left in the dish. Please let me know the proper way to water. (E-mail reference)

A: Plants don't know the "rules" that we lay down for them, so when someone breaks the rules and the plants don't die, we "rule-makers" have a problem. What your friend is doing is letting the force of capillarity through cohesion of water molecules do the watering. She is apparently clever enough to time the placing of the water in the saucer and have just the right amount of water taken up by the soil and plant roots so nothing remains in the saucer to cause problems. Since you are a beginner, water from the top until the water appears in the saucer, letting it stand for no more than 30 minutes like that, and dump or aspirate the excess out. Send me your mailing address, and I will send you a copy of my publication "Home Propagation Techniques."

Q: Every year my alyssum has some infestation by small black hopping bugs, but this year seems to be particularly bad. What is the name of these bugs? Why are there so many this year? I have powered with Sevin-10, which helps, but doesn't eradiate as in past years. The ground below the flowers is black with the insects. (Sykeston N.D.)

A: This is likely some species of flea beetle that has fallen in love with your alyssum and is developing a resistance to the Sevin insecticide. Unfortunately these adult beetles have the ability to overwinter under leaf litter and other debris to begin feeding and laying eggs the next year for another generation. The first step in control is to clean up everything possible this fall, removing or limiting any hiding places for them. Next, using a selection of insecticides will help; alternate Sevin with Malathion, then Orthene, etc. This keeps the beetles from building up resistance to one insecticide. These characters are a problem once they get established, so don't expect the battle to be an easy one.

Q: I'm having trouble with scale on my trees, especially my green ash trees, where they are so thick that they’re almost on top of each other. The trees have a lot of dead branches. They are also on my apple and apricot trees. I have used ACECAP 97 twice on my ash trees, but was told that I probably shouldn't do it every year. Also I can't use this on my fruit trees. I have sprayed them a couple of times in the fall with dormant oil spray. What can I do before all of my trees die? (Tioga, N.D.)

A: The dormant oil should be applied in the early spring, just as or before the leaf buds open. It sounds like you have a near impossible situation to bring under control. Unless scale is caught early, it can be difficult to eliminate. Timing sprays to kill off the crawler stage is important, but unless you are a competent entomologist you will succeed only by luck. You might try summer oils, which are a lighter consistency and will not be toxic to the plant in leaf. Other than these recommendations, I have nothing else to offer. Sorry!

Q: My mom has had a jade plant for around 10 years. It is beautiful and huge. We think it has some sort of fungus. There is a mold type fungus that has been spreading from leaf to leaf. We are not sure where it came from. Can you please help us figure out how to treat it? (E-mail reference)

A: Try to get some of Schultz's Fungicide 3. It is an excellent product from the Neem tree that provides control of fungi spores, insects, and spider mites. It should be available in any major garden supply outlet.

Q: I have a question about an oily film that has been covering the trees in our area. I have 36 acres of poplar forest and it is covered! This sticky oil is all over trees, shrubs, vehicles, etc. Some tree leaves (eg. saskatoons) have been turning black where the sticky oil is. Do you have any idea what causes this? (E-mail reference)

A: The oily film you are making reference to is very likely honeydew from aphid infestations, which seems quite common this year, especially on poplars. You might do some close examination and find the trees literally crawling with ants. This is a good indication that the aphids are up there, as the ants "farm" the aphids for maximum honeydew production, which the ants harvest as a food source for themselves. The blackness is a sooty mold that is a secondary fungus from the honeydew, and if it is intense enough, can result in the indirect death of the plants due to a cut-off of light to carry on photosynthesis. I think spraying is impractical on 36 acres of trees at this time. You might consider dormant oil spraying next spring before new growth begins, which will take care of most of the overwintering individuals and be less toxic and less expensive than conventional spraying.

Q: A client has boxelder trees and lots of boxelder bugs. Any ideas she can use to get rid of the bugs? (Linton, N.D.)

A: Boxelder trees attract boxelder bugs. There are two ways I know of to rid the area of them: remove the trees (not likely!) and spray with Malathion, Asana or Warrior.

Q: Our mugo pines are about 12 years old and are in need of trimming. When do we trim them and how far back can we cut them? They are about 5 feet tall and starting to cover the front window of our home. (Parker, S.D.)

A: Mugo pines are best pruned in the spring prior to the new growth breaking. Always cut back to where needles are present, not bare stems, or, cut back to a lateral branch.

Q: I just moved into a house. My back yard is fenced and needs character badly. I'd like to plant shrubs all around the fence to make it more private and am thinking about a couple trees at the back of the yard. What would you suggest for a nice shrub for this part of the country? Flowering would be fine but not necessary. (Moorhead, Minn.)

A: That's what I like -- an open field! Here are some of my favorites: Anabelle hydrangea, Amur maple, Viburnums (nannyberry and many others), lilacs (of course), American elderberry and Juneberry. That should be enough to whet your appetite!

Q: I have a question about so much smut on the sweet corn. We have been getting sweet corn from my wife's brother. He has a good size plot and likes to raise corn and give it away to his friends. He was quite concerned about the problem of smut this year. He has had different maturity corn but I don't know the seed company. The last corn we got was a later maturity and it had a thinner ear, smaller kernels and a few white kernels. It was just maturing. Could have used a couple more days but it was good. The amazing thing was it had very little smut. Next to none. Could the later maturity have something to do with this? (Breckenridge, Minn.)

A: Corn smut thrives in warm weather, with the optimum being in the 80 to 90 degree F range. The best control is to follow good sanitation practices and plant corn hybrids noted for good vigor and resistance to this fungus. Crop rotation may help somewhat, although it can be spread via birds and insects from other adjacent areas.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

###

Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu