September 25, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: Someone in the area just called and said that her jalapeno peppers are very mild this year. They are as mild as a bell pepper. What could be the cause? (Bowman, N.D.)

A: Could be the wrong pepper or they could still be immature. Mine are nicely sinus clearing, voice changing hot! I suspect the wrong pepper.

Q: What would be our options for controlling orchardgrass in a lawn? Is there any selective herbicide for control or are we limited to spot spaying and reseeding? (Hettinger, N.D.)

A: Orchardgrass is a perennial so there is no selective herbicide for control. Your options are limited to spot spraying and reseeding.

Q: I am thinking about planting mature silver maples. What should I look for? For example, would a 6-inch diameter tree be too large? (E-mail reference)

A: Forget the mature ones, they are expensive and don't transplant well. I would suggest planting something in a bushel or 10 gallon container. They grow quickly and you can appreciate their growth.

Q: I have a ficus tree that is probably 10 years old. I moved it to a different location in my living room and it started growing new branches and leaves. Now it is losing all of its leaves and new growth. It is almost bare, and not too long ago it was full and getting really pretty. The tree is more than 5-feet tall and planted in a large pot. Other than the leaves falling off, it looks perfectly healthy. (E-mail reference)

A: Check for scale or mealy bug infestations. It could be a difference in light intensity at the new location. If the cambial tissue is still green under the bark, the tree will very likely come back with new leaves that are adapted to the new location.

Q: A lady planted russetts, norland and kinnebec spuds this past spring. She has lots of vines but very few tubers. My guess was too much nitrogen but she says no fertilizer, compost or other material has been added to her garden for years. We had lots of rain early then nothing but hot and dry weather for the past eight weeks. (LaMoure, N.D.)

A: In a word, drought. Potatoes need moisture to develop decent tubers and without it nothing but pips develop. Being shallow rooted, they are sensitive to a lack of moisture in the upper soil profile. When that is coupled with 100-plus degree days like we had last month, you won’t get much in the form of tuber development. Being a member of the nightshade family, the vines will thrive in the heat, and it will take more than the drought we had to kill them.

Q: How do you tell when watermelons and melons are ready to pick? (E-mail reference)

A: The best way is to pick one that you think is ripe and cut into it. You will also see ground color changes and stem shrink. Depending on where you live and when you started your garden, you should be picking them by now.

Q: I have some alpine currant bushes I planted in front of my house four years ago. For the last two years something has been eating all the leaves. I have sprayed and dusted. I don't know what to do next. (Sabin, Minn.)

A: I’m not sure what insect may be doing that. I suggest spraying the shrubs with a dormant oil just before leafing-out. Spray with Orthene immediately after leafing-out, assuming you are not going to harvest the fruit.

Q: We have an alpine current hedge that I believe has a fungus problem because of our excessive moisture this spring. We sprayed it a few times but the problem continued. The leaves curled and were almost black. We recently cut it back to 6-inches in height and used the power washer to clean out all debris. Will we have a hedge next spring and what can we do to prevent this from happening again? In another location our alpine current hedge developed brown, dry looking leaves. It was newly planted last spring. I cut it back a few weeks ago and it is coming back nicely. (Washburn, N.D.)

A: Anthracnose, cane blight, and rust can be expected under the kind of conditions we had last spring. If the hedge was healthy and well-established other years, it should come back next spring. Do a protective application of a Bordeaux mixture after the plants have fully leafed out. Repeat every 14 days until mid July.

Q: I plan to protect some shrubs for the winter by wrapping them in burlap. When's the best time to wrap them? Anything special that needs to be done at that time? (Jamestown, N.D.)

A: The best time to wrap the plants is when they are completely dormant but before freeze up, which is usually around Halloween.

Q: I have a rather large garden where the soil has turned to cement. The plan is to add some city compost to it and rototill it in. The clematis in our garden have been there for well over 10 years. How far away from the clematis do we need to stay so that the roots are not damaged? I would also like to take two sections from the clematis but after looking at it closely, I only see four stems coming out of the ground. I'm afraid that I will damage the plant. Should I just buy some different ones to plant? (Moorhead, Minn.)

A: That last idea of yours sounds like a good one. You don't want to mess with something that is as happy as your clematis appears to be. It should suffice if you stay a good 24 30 inches away from the plant. A word of caution about the compost, get it tested first. I found the compost from Fargo to be very high in salts when I tested it years ago. If diluted with sufficient soil, it isn't a problem. Salt toxicities begin to occur with sensitive plants if the compost volume is higher than 20 percent in the root zone. Since the compost material is collected from all over, there may be some herbicide residue that has not broken down into harmless metabolites. If it is really important to you to improve your soil, I encourage you to get some sphagnum peat moss this fall, and work it into the soil.

Q: I have four apple trees that are infected with apple maggot. I sprayed once this spring when the flower petals were just beginning to fall, but missed the second spraying. It seems every apple on the trees is infected. The trees themselves are healthy and full. Is there anything I can do this fall to get a jump on it for next spring? (Woonsocket, S.D.)

A: The best thing is good sanitation. Clean up all apple and leaf litter this fall. Next spring, while the tree is still dormant and just before the buds open, spray the entire tree with dormant oil. Then spray with an insecticide like Malathion after the flower petals are at full bloom, and about a week later, as they are falling. As an extra measure, get a false apple or two that is covered with a sticky material and hang them on the tree. This will trap some of the females that may be moving in from another area. You should have fairly clean apples then!

Q: We have a huge maple tree in our yard and grass does not grow well beneath it. We finally found some "special" grass seed that we planted about Aug.1 and some about Aug.10. Now we have very thick grass that is 4 or 5 inches tall. Should we mow it before freeze up or let it stand through the winter? The leaves are going to be a difficult to rake this fall if we don’t cut the grass. (Aberdeen, S.D.)

A: Mow it. Set your mower at the highest level and collect the clippings. A week later, lower it to 2.5 inches, mow and collect the clippings. At the next cutting, set the mower to 2 inches and collect the clippings. Keep it hydrated as long as you can going into the winter without soaking it. If the grass continues to grow into October, keep mowing it at the last setting.

Q: I have a beautiful mandevilla vine that I don't want to lose to frost. Is there anyway I can winter it in the basement or somewhere else in the house? Should I cut it down or leave it the way it is? (E-mail reference)

A: Mandevilla vine can take the low 40's without a problem. I would suggest cutting it back to 12 inches or less and back off on the watering. If you can, find a liquid fertilizer with an analysis of 10 50 12 or something similar. This will not stimulate the growth so much as it will help to toughen the plant to survive the winter indoors. Allow the plant to remain outdoors as long as possible. Dig it up and bring it inside putting it in the brightest spot possible. Water it just enough to keep it alive. You do not want to stimulate too much new growth, as it will not do well in the dry interior of a home. Next spring, move the plant outside after the danger of frost is past. Expect any growth produced during the long winter months to be burned off. That is not the death of the plant, but a re orientation to a new environment the plant is going through.

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: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu