NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

October 15, 1998

Hortiscope

Ron Smith, Extension Horticulturist
North Dakota State University

Q: What is best to put on strawberry plants for winter, and how should I care for my asparagus? Is it OK to put orange and grapefruit peeling in the garden? Is it OK to till poplar leaves into the garden? (Gackle, N.D.)

A: Either put up a snow fence around your strawberries, or cover them with clean straw, right after freeze-up but before serious snow falls.

Allow the tops of your asparagus to remain. They will influence snow collection, which will provide critical moisture next spring.

I'm assuming that you are composting your peelings first— if so, then OK. If not, then no.

You can till the poplar leaves into your garden soil. Just don't overdo it, or you will tie up nitrogen next year.

Q: Can you please tell me what the enclosed sample is, and how to get rid of it? It seems to be taking over my yard, along with violets! (Jamestown, N.D.)

A: From what I could tell of the partially decomposed sample, that it appeared to be foxtail, an annual weed that can be controlled with a pre-emergent herbicide like predimethalin. The violets will require repeat applications of Trimec.

Q: Enclosed is a sample of leaves from my linden trees. Can you tell me what is causing the leaves to curl and turn brown and what to do to cure the problem? (Moorhead, Minn.)

A: Your lindens are showing a number of problems: herbicide injury, a fungal leaf spot disease, and root zone problems—either a root-rot, elevated water table, solid compaction, or some of all the above!

With the herbicidal injury, (curled leaves) you can only hope the trees will outgrow that. With the fungal leaf spots, spray new foliage next spring with an all-purpose fungicide, like Daconil 2787. With the root problem, either reduce watering, move the plants, raise them, cone aerate or accept the fact they will die in a year or so.

Thanks for writing. Sorry the news wasn't better.

Q: We have three flowering crabs, and two are beautiful but one isn't. The one seems to have less leaves and is lighter in color than the others. I have tried fertilizer spikes and more water, but it didn't seem to help. What should I do next? (Rogers, N.D.)

A: I would suggest aerating out around the dripline of the tree next spring. Spray the tree with lime-sulfur before leaf break next spring. This is a "tonic" recommendation that often solves these unidentifiable problems!

Q: Can you tell me what will kill the weeds in my strawberry patch? Also, my apricot tree was full of blossoms, but the apricots got 1½ inches in size and they soon disappeared. Why? Can you also identify the enclosed sample of a weed that is taking over my garden? (Erie, N.D.)

A: Review information on weed control in strawberries contained in "Strawberries" (H-16), a publication of the NDSU Extension Service. Be sure to use the correct type of herbicide at the right label rate. Basically, Dacthal will control germinating weeds, while Poast is used for grass control. The only guess I can come up with is that squirrels thought they had a priority right to your apricots. I'm sorry, the weed sample had rotted beyond any possible recognition by the time it got to me. Please try again, but pack it dry, rather than moist. Thank you!

Q: When should I spray my apple trees to thin the crop, and when is the correct time of year to prune my Norway maple? Last time I pruned it in March, and it drained from the cuts. What is the difference between lime-sulfur oil and dormant oil? Can they be used together if needed? Also, how many years does fruit tree spray stay good in the bottle? Thank you. (Stickney, S.D.)

A: Spray when in full bloom, and again at flower petal drop. Maples are noted for their "bleeding" during early spring pruning, but this causes no real harm.

Yes, dormant oil and lime-sulfur can be used together. Dormant oil smothers insect eggs, while lime-sulfur acts as a "sanitizer" of the plant above ground surfaces.

How long a product stays "good" depends on how it is stored. If not allowed to freeze, three to four years does not seem unreasonable.

Q: I have an azalea that flowered and now I am wondering if I should remove the brown parts that are left after the flowers died? I had it outside until it started to get cold, but everyone is telling me to just throw it away! Is there any way to keep it alive, I would hate to have to throw it away. I also would like to know how to overwinter my two miniature pink rose plants that I had in pots this summer? I also need to know how to care for houttuynia? (Valley City, N.D., e-mail)

A: Unfortunately, your friends are right about the azalea. The fact that you have kept it alive this long brings it close to being entered in some record book! Here is a litany of their problems: they don't do well with hard water, alkaline soils or dry heat. They like to be kept moist, but not water-logged. If the soil dries just once, the leaves fall. If you still want to try, I suggest going for an all-peat potting soil, and watering with distilled water. I don't know how big it is, but if you can, place a clear glass (or plastic) fish bowl over the plant once the heat comes on. This will create a "terrarium effect" and keep the humidity high. If this proves to be too unwieldy, place the potted plant in a larger pot that is filled with sphagnum peat moss to keep the humidity high and the roots cool. Place in bright, but indirect light for the winter, in the coolest, above-freezing location in your house.

Don't be discouraged if the plant bites the dust. You honor your mother's memory by at least trying. I suggest photographing it along with some cuttings, and attempting to root them.

I think roses fail as houseplants because people attempt to keep them going on a year-around basis. Give them a winter of rest in a cold location, then begin the "TLC" around mid- to late-March to get them back into bloom again.

Concerning the houttuynia (hoo-TY-ni-a), I would guess that you could do anything you want. It is a hardy perennial for our area, so you could allow it to stay out, and bring it back in for the winter. I am afraid that plants like this will die if not given a winter rest at, or close to, normal winter temperatures. By the way, it is also know as the chameleon plant.

Q: I live in northern Minnesota and have sandy soil. I am wondering if you could give me some information on growing a nice lawn. (Clearbrook, Minn.)

A: Work in as much organic matter, such as peat moss or compost as possible. Incorporate superphosphate into the top 4 to 6 inches of soil at about 20 pounds per 1,000 square feet. Fertilize, seed and if possible, hydromulch the area, and keep moist until germination is evident.

Sand requires a strong commitment to watching water requirements for a sucessful lawn.

Q: Can you tell me what kind of vine I have enclosed and how to care for it? (Bemidji, Minn.)

A: Your leaf very strongly resembled a grape leaf, although it was much larger than I've ever seen. If it is, you should be, able to just let it grow as it has in the past years. Grape vines are, or should be available at most nurseries or garden centers in your area. You may want to start out with Beta grapes as they are hardiest in our part of the country.

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Source: Ron Smith (701) 231-8161 ronsmith@ndsuext.nodak.edu

Editor: Dean Hulse (701) 231-6136