NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5665
April 8, 1999
Hortiscope
Ron Smith, Extension Horticulturist
North Dakota State University
Q: What chemical product can be used to control weeds and thrips in a plot of gladiolas? I prefer to garden organically, but I am also having problems with weeds in a plot of sweet corn. (Lake Benton, Minn.)
A: You'll have a tough time controlling thrips in your glads organically. I have never been successful. You can try insecticidal soap if there are no predatory insects present. Otherwise, use Orthene (a contact/systemic) to control them.
I would suggest presprouting the weed seed and killing off the seedlings with Roundup. Or, you may want to try solarizing the area by covering it with heavy clear plastic for about two weeks prior to planting. The weeds will sprout and stay soft, with some drying. Those that don't are easily rogued out when the plastic is removed. Plant your sweet corn close. Hand cultivate while canopy is open (usually until July 4th or so) then let them go. The corn will form a dense enough canopy so that the weeds beneath it will be weak enough to be noncompetitive. Otherwise, there are many herbicides that can be used in sweet corn.
Q: My problem lies with a cactus. Its size is getting to be a hindrance and it seems to grow best when placed outside during the spring and summer months. Is there some way to maintain this plant at a given size? Is there any way to straighten out crooked leaves? Also, could you recommend a book on cacti that might answer more questions as they arise? (Forman, N.D.)
A: There are dozens of cacti species that you could be making reference to, so I cannot accurately advise you. As far as books on this genera, I suggest a visit to a bookstore and do some browsing. I do not have any specific books on cacti, so I am unable to make a recommendation.
As far as the crooked leaves go, why not let them add character to the plant? Assuming you rescued this plant from the desert Southwest, I'd encourage you to continue summering it outdoors.
Q: Enclosed is a picture of my 4-year-old Colorado blue spruce. It seems to have about three or four leaders and I am wondering if I should cut all but one of them off? (Eureka, S.D.)
A: Judging from the good photo you sent me, I would say just leave it alone. A leader will emerge naturally -- in fact it appears as if one already has. Enjoy the natural growth of this tree. It will increase in beauty with age!
Q: I would like some information on how to get rid of or control chickweed in a vegetable garden. (Crosby, N.D.)
A: Treflan (trifluralin) will control chickweed in most garden crops. Obtain some from a local garden center and follow label directions for your particular veggies. It is a preemergence, so it will not work on the chickweed if it has germinated.
For those early volunteers I suggest simply pulling the chickweed. It is easy to pull, but make sure you get it before it sets seed.
Another option is to dust the chickweed with ammonium sulfate while the morning dew is still on it -- guaranteed to burn it down.
Finally, why not try cultivating it? It can be used in place of lettuce in sandwiches or as a component of salad. Some people have also cooked it like spinach. Fate sometimes is fickle -- if we try to kill it, it persists; cultivate it lovingly and it dies!
Q: I have heard that hybrid seed will not germinate in 2000 due to the Y2K bug -- and that there will be no seed available in 2000, so everyone should buy enough seed for 2 years. What's the basis for these concerns, and is there any truth to them? (Moorhead, Minn.)
A: I don't know what the basis could be, other than pure irrationality and the desire to invoke fear or panic. There is no truth to these comments or beliefs. Seed does not have a timer keyed to our annual cycles -- it could be the year 4000, or the year 01 -- the seed doesn't know the difference!
Purchase what you want or need now and don't worry about the Y2K bug affecting anything in horticulture! The seeds, plants, trees, shrubs and lawns all respond as they have in past years -- depending on the care they get!
Q: Is there a way to control sprouts from box elder trees? Last spring, I cut down a bunch of small box elders with trunks 3 to 4 inches in diameter. By fall I had a nice crop of new shoots coming up from the stumps. (e-mail)
A: If what is coming up are seedlings and not attached to the mother tree then an application of Roundup will take them out. If they are attached via the root system to the main tree, then some damage to that tree could be expected.
At one time, there were sprout inhibitors on the market, but the manufacturers did not re-register under new EPA, rules and the products had to be taken off the market.
Q: We inherited a black ash, probably the cultivar Fallgold, which is positioned between the street and sidewalk here in Fargo. Having seen few large trees of this ash species I have no idea how wide it will get or how high up I should let the canopy start. It is about 8 feet from a streetlight and our main concern is keeping the branches from bothering pedestrians. Does one try to shape the black ash to have a single strong trunk under these conditions? The tree is only 5 feet high, but I like to prune the branches off before they get wider than a nickel, making sure to cut outside of the branch collar as is recommended these days. What is your advice on shaping this step-tree of ours? (Fargo, N.D.)
A: The black ash is a beautiful tree that is similar to the green ash, except that the canopy spread is somewhat less -- getting to about 15 to 20 feet in your situation, compared to a green ash that can get twice the size.
Ashes in general need little corrective pruning. If your tree has been planted for at least two years, you can then remove the smaller branches that will have the potential to interfere with pedestrian traffic or the street lamp.
This species is not as drought tolerant as green ash, so if we get into an extended period of no rain, then you should give it a good dose of water. Go ahead and get the pruning out of the way now.
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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.
Source: Ron Smith (701) 231-8161 ronsmith@ndsuext.nodak.edu
Editor: Dean Hulse (701) 231-6136