September 20, 2001

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I’m raising winter squash. When should I stop watering it and how do you tell when the squash are ripe? Also, can you water cucumbers too much? (Opal, S.D.)

A: The squash vine roots are extensively developed by now and should not need further supplemental watering. Ripe winter squash will have a shell hard enough to resist pressure from a thumb nail. I’d let them stay until frost hits the vine. Yes, you can certainly water cucumbers too much!

Q: How do I get rid of the nightcrawlers in my yard? Also, should the last cutting of the grass in the fall be long or short? (Wing, N.D.)

A: Treat your lawn like it has an infestation of grubs. Simply follow directions or the bag of Sevin for grub control. It will then take care of about one third of the nightcrawler population.

Cut the grass about an inch shorter with the last mowing.

Q: I have about 30 beautiful bell pepper plants, but less than half of them are producing fruit. I have them about 18 inches apart, have a good layer of straw mulch around them, and water profusely. (Audubon, Minn.)

A: Pepper production is about as much an art as it is a science. They will produce poorly or not at all under the following conditions: fluctuations in temperature or water availability; too high soil fertility, especially nitrogen; transplanted too late or too old at planting; if they were too cold or too dry sometime before planting or too chilled after planting, or night temperatures below 60 F that cause blossom abortion.

Q: Can you tell me what the enclosed vining plant is? Also, are you still doing your great column? I can’t remember seeing it lately. (Devils Lake, N.D.)

A: You sent me a good one, something I had not seen for a couple of decades! It appears to be the common moonseed, Menispermum canadense, a deciduous vine that is too weed-like in growth to be of any real value horticulturally. Yes, I still write my weekly columns, but where or when it appears is up to the local editors. You can get the full scope of Hortiscope by logging on at: www.ext.nodak.edu/extnews/hortiscope/contents.htm 

Q: Can you tell me what is wrong with the enclosed rose bush and strawberry leaves? The strawberry leaves are from a new patch that started out good, but during the summer some of the plants started turning yellow. Is this a condition of the soil or disease? What can I do to remedy it? (Bowdon, N.D.)

A: Both plants are showing an extremely bad case of iron chlorosis, most likely induced by high soil pH. There is a good chance this can be corrected with the application of chelated iron on a regular basis. I suggest making the initial application just before new growth emerges next spring. After that, monthly applications should keep the problem from showing up again.

Q: Can you tell me the correct name of the enclosed vine that grows up in my lilac bushes every year? It is very fast growing and would work really well for someone with a trellis. Also, in the past I had a snowball bush that seemed to get infested with aphids all the time. I sent for some green leaf insects. When the eggs started hatching I placed them on the bush and it took care of the aphids. I am a bird watcher and was afraid to hurt the birds if I used chemicals to spray the aphids. (Faulkton, S.D.)

A: You are blessed with the vigorous vine Clematis tangutica. The beautiful bell-shaped flowers are only surpassed by the numerous feathery seed-heads. It has probably escaped from the wild and found a suitable home amongst your lilacs. I encourage you to attempt to move it to a new location after everything goes dormant. Any clematis is too beautiful to kill off.

Q: My honeysuckle vine is not looking very good and I was wondering, when is the right time to prune it? I need an explanation about letting grass go dormant. A friend and I are not agreeing about the correct length of time that grass will survive without water. Could you also tell me how to overwinter a silver lace vine? They always die for me. I live in sandy soil in South Dakota. (Carter, S.D.)

A: I suggest pruning the honeysuckle vine back completely after a killing frost. Spray new growth with a fungicide like Bordeaux mixture next year. Grass will go dormant (the cool-season ones like Kentucky blue, fescue, etc.) when the temperatures get above the mid-80s and nature’s water is shut off. Dormant grass can go about two weeks with no water before it begins to die; if it goes a whole month, it is probably all dead. Keeping it dormant and alive requires a light watering, 0.25 to 0.3 inch every 10 days. If enough water is given to pull it out of dormancy (1 to 1.5 inch per week) then it had better be delivered every week to keep it from going dormant again. The dormant/non-dormant cycle, if repeated too often, will exhaust the lawn of carbohydrate reserves, weakening it and predisposing it to disease and insect problems. Wrap up the vine in a burlap bag filled with leaves, and mound some soil over the crown, about 12 to16 inches, after a hard late October freeze.

Q: I have a rose bush that is getting too large. How far can I trim it down and not kill it? Also, when should I cut off my peonies and iris? Should I do it now? (Valley City, N.D.)

A: You can trim the rose bush down to 12 to 16 inches or so. While you can cut the iris and peonies off any time now, I always believe it is best to wait until after a frost.

Q: Can you tell me what is wrong with my yard? My peony bushes are full of holes and the snow on the mountain and lily of the valley are brown and dying. Is this a disease or a soil deficiency? (Jamestown, N.D.)

A: The peony plants are apparently on the dinner menu of the local slug population. The other plants appear to have downy mildew. Best treatment is to rogue out affected plants and spray the rest with Bordeaux mixture.

Q: What has happened to my marigolds? I planted nursery plants in pots on the south side of the house and also some in the ground. They have been just beautiful until about two weeks ago. They look like they are drying up from the root up to the flowers. Could I have watered them too much? (Fessenden, N.D.)

A: The marigolds have white mold, a fungal disease that often develops late in the year following a summer of high rainfall or heavy overhead watering. Be sure to clean everything up this fall and try to use drip irrigation next year.

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.

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