NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5665
April 29, 1999
[EDITORS: Could you please include the following message, or some such verbiage, in this edition of Hortiscope? Note to readers: Please include your name and address with all the letters or e-mail messages you send. Any correspondence without a name and address cannot be answered. Thank you.]
Hortiscope
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Could you tell me what cut flowers I could plant that would still be blooming in September. I would also like to know the best way to keep them in a vase to use as a centerpiece? Would Poast be OK to spray between my shrubs, plants or trees to remove grass? The deer broke off some of the branches on my Japanese lilac and I am wondering if it will come back or if I should get rid of it. I also am wondering if I can cut back my potentilla. My last question is if it is better to plant onion sets or onion plants. (Winner, S.D.)
A: Just about all the asters and mums would be at their peak in September. The eustomia or lizanthus makes a beautiful cut flower, as do snapdragons, zinnias, marigolds and a daisy known as Osteospermum Passion Mix.
Poast should not cause any problems as long as you follow label instructions.
Let the lilac go. It will likely come back—they're pretty tough. If you don't see any growth in 30 days, get rid of it and replant.
Pruning the potentilla selectively will not keep it from flowering; cutting it back completely at this time will—all you'll get is lush, green growth.
A horse apiece on the onions! Try both and see what results please you the most.
Q: I have a geranium that has been in the house for two years now. The problem is it does not bloom, even though I have cut it back and repotted it. Could you please give me some advice on how to get it to bloom again? It does get plenty of sunlight. (e-mail)
A: I'll bet it doesn't! Get plenty of sunlight, that is. Geraniums are sun lovers! Bright, direct light is what they need, and plenty of it to bloom, especially the Martha Washington types. Try summering it outdoors and see what happens.
Q: We bought a house in Fargo and with it inherited a flowerbed full of pigeongrass and a garden plot that became grassed over and essentially an extension of the lawn. I spaded the soil up last fall and this spring plan to take a tiller to it and then use Roundup. What would the proper timing be for these two treatments? Will one application of Roundup be sufficient? What kinds of vegetables and flowers can I plant after the Roundup? (Fargo, N.D)
A: Pigeongrass and other annual grasses can be effectively controlled with a material known as pendimethalin, commonly available on the retail garden market.
Roundup has no soil activity, so there is no waiting period. However, it is a good idea to wait until you are assured of a complete kill of the unwanted vegetation before working the soil up. This usually takes about seven to 10 days, depending on the weather.
Till as soon as the soil can be worked; then treat with Roundup when the weedy growth appears. Give it about 10 days to make a good showing. Generally, one treatment of Roundup will be sufficient, according to my definition. You will never be 100 percent free of weeds, so don't even hope for it.
Q: A certain television personality in the gardening field recommended household ammonia and Coke in one of those hose-end sprayers for feeding. Is this a safe, effective way of foliar feeding trees, shrubs and flowers? (e-mail reference, Fargo, N.D.)
A: Coke and ammonia in a hose-end sprayer to foliar feed? In my estimation, a very ineffective way to feed plants! Ammonia is a very weak source of nitrogen and would likely mostly volatilize. The Coke must act as a sticker, as I cannot think of any other possible contribution it would make. If you want an effective foliar feeding fertilizer, go with the products that are formulated for that purpose.
Q: I have a couple of questions for you. What can be done to control moss but won't kill the grass? Mice have feasted on the bark of an apple tree this winter. What should be done to the chewed area? (Stanley, N.D., e-mail)
A: Moss development in turf areas is the result of too much moisture lingering in too shady a location. Permanent elimination of moss and algae can be achieved by allowing the soil to dry or drain better. This can often be accomplished via selective pruning, (if the dense shade is tree caused), core aeration and/or regrading the soil surface. Temporary relief can be achieved with the application of about four to six pounds of iron sulfate or about 10 ounces of ferrous ammonium sulfate per 100 square feet.
If the trees have not been girdled, then simply take a sharp knife and make clean edges around the damaged areas. No need to put on any type of dressing. The tree will begin a healing process faster that way, if it is going to heal over at all.
Q: Should I cut back the dead foliage on the lamb's ears. And also, how should I prune my forsythia? (e-mail)
A: Yes, go ahead and remove the foliage on the lamb's ears, being careful to not damage the newly emerging foliage for 1999.
Pruning forsythia requires no special skills. Simply cut back the oldest, heaviest stems as close to the ground as possible. They flower on last season's growth. I have tried to kill one that has overgrown my property by cutting it back severely—and still it grows and flowers! If yours has flowered already, then cut those canes back. This is one of the best plants for abuse tolerance, so don't worry about making mistakes. The plant will recover and forgive you in a year or two.
Q: I have violets of various colors and sizes that I have started from putting a leaf in soil. My problem is that after growth some of the leaves droop because they have stems on the edges that are 6 inches long. Should I keep these trimmed off? Sometimes some of those outer leaves become opaque and the stems dry up. (Ipswich, S.D.)
A: I suggest clipping them off. In their native habitat, they are ground-cover type plants, with the leaves rooting when they touch the moist, organic soil. You might try putting an empty pot next to one of your mother plants with the extended leaves and pinning them onto the soil surface to root.
Q: I am having trouble with worms inside my plums when they ripen. There is no evidence of entrance, so I am assuming they lay their eggs in the blossom. Is there something I can spray the trees with at blossom time that is not toxic to my honey bees? (Hague, N.D., e-mail)
A: You are most likely seeing the grub stage of a beetle known as the plum curculio. They lay their eggs in the developing fruit, leaving a small, corky, crescent-shaped wound. The adults for the 1999 season are in the pupal stage in the ground litter and fallen fruit that is around the tree right now. A good spring cleanup would go a long way in reducing their population.
A spray schedule would be when the fruit has just set and the temperature affects their activity. Around 70 F brings the beetles out, and they begin their feeding and egg laying. The best key for spraying is just about when all the flower petals have fallen. The bees would be finished then, and the beetles would just be getting started. Materials to use are either Sevin or diazinon. Repeat again in about 10 days.
Q: I started seedlings of scarlet cardinal climbers. They have two to three sets of leaves. I noticed they have the tiniest white, almost clear bugs all over them. How do I get rid of these pests on these young plants? I have several plants that I brought in last fall, and I think they may be the culprits. (e-mail reference)
A: Not likely spider mites, but probably white flies or scale. Anyway, give the plants a good shot of insecticidal soap, available at most garden supply stores. Check the plants carefully over the next couple of weeks to be sure that none have been missed. This is a contact spray only, so be sure to get the foliage completely covered, especially the leaf undersides.
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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