May 2, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: Our family moved into our new home last fall -- too late to put the lawn in, unfortunately. So we're going to seed it this spring. The final site preparation was done with a track loader, so the soil was packed pretty firmly and was left pretty rough. We evened out some of the biggest humps and holes last fall with a small tractor and our open winter has helped to break down the big lumps and clods. Our plan for this spring is to rototill the entire yard, rake out any lumps and rocks and finish leveling out the site (maintaining proper grade away from the house, of course). Per the recommendation in your circular "Turfgrass Establishment and Maintenance for Home Lawns and Athletic Fields" we'll probably go over the lawn with a ballast roller and apply a starter fertilizer before seeding. I know we're in for a summer of watering and weed battles. Can I apply the fertilizer and seed by making two trips (perpendicular) with a broadcast spreader? In the publication you mention the use of a preemergence herbicide to control annual grass-type weeds with a fall seeding. Is it appropriate to use that herbicide with spring seeding? We're planning to get to work and get the lawn seeded as soon as the soil is dry enough to till. Do we need to be concerned about frost? Any other advice or suggestions? (Fargo, N.D.)

A: Boy, do you ever do your homework! First, the last question, no, you don't have to worry about frost. In fact, frost seems to aid in getting the seed to germinate. Now, concerning the weeds. Unless you can find Tupersan (siduron) which is the only pre-emergent on the market that will control grassy weeds like foxtail and barnyard grass while allowing the bluegrass and other cool-season grasses to germinate, don't apply anything else. The weeds and grass will have to co-exist for awhile, until the grass matures somewhat, for about 5 mowings. Then, you can get a post-emergent herbicide and apply it to kill off the grassy weeds before they go to seed. This should be done before the first of July, keeping an eye on the weather for rain and excessively high temperatures. Fertilize the lawn this fall with a complete fertilizer; mow high and frequently (2.5 to 3 inches high) without waiting for every seed to germinate and often enough that you don't leave windrows of grass when you are finished. This will require attention to accomplish this with the flushes of growth that take place in the spring.

Q: We are having a problem with creeping Jenny. Do you know of a spray that we can use that will not harm our lilac hedge or any other flowers? (Lehr, N.D.)

A: There is nothing that you can spray to kill this weed that will not also harm the ornamental plantings if any drift occurs. Careful application of Trimec, just to wet the foliage, not soak it, and protecting the desirable plants from drift spray should do the job with repeat applications. This perennial weed, like all other such weeds, are most effectively controlled when herbicide applications are made in the late summer or early fall.

Q: We have a peach tree seedling that is about 24inches tall. Can we prune it to make a dwarf tree? We thought we'd try making a container plant with it. (Gwinner, N.D.)

A: Good luck! You can prune it to make it more shrub-like, and keeping it in a container will allow you to move it in during the winter where it can go through a cold period but not freeze to death. Be aware that I have found the bunny and deer populations have a nose for peach trees in our area. I have been frustrated twice attempting to grow peaches in North Dakota, only to have them completely wiped out by these cute but destructive creatures.

Q: Someone's friend wants to use garlic bulbs intended for planting in food preparations. Are bulbs for planting treated with pesticides or other things that we don't want to eat? ( Fargo, N.D.)

A: Garlic cannot be treated with any pesticides, so the "seed garlic" (a misnomer of course!) can be eaten. That is usually the largest collection of cloves that will, in turn, produce the largest bulbs at harvest.

Q: I am trying to get rid of daylilies in my yard. I have used Roundup two or three times and yesterday spent three hours digging up bulbs. I cannot seem to get all of them. Do you know of some other treatment I can put on these daylilies to kill them? I will soon be planting two spirea and some ornamental grass in this area. How long after using a killing treatment should I wait to plant these? (Moorhead, M.N.)

A: Daylilies can become a lovable weed when you want to get rid of them. I can offer no suggestions other than what you are presently doing. If you are referring to Roundup as the killing treatment, you can plant any time after you have seen the effects starting to take place.

Q: A homeowner here in Minot has field pennycress growing in a lawn seeded last fall. It is a heavy infestation and the weeds are already more than 3 inches tall. A TRIMEC label says "Do not apply to newly seeded grasses until well established." If he doesn't spray, he may end up with a forest of weeds. What would you recommend? ( Minot, N.D.)

A: Worry not. Have the homeowner cut the grass three to five times this spring to "toughen" it up a little, then make the application after that last cutting. Apply the herbicide at label rates and all should be well. He should not apply herbicide if you are in a hot spell -- 80's or higher -- for at least a day or two after the intended application. It will probably take another application late this summer or early fall to finally do it in, but an application now should keep it in check somewhat and hopefully weaken it enough for the coup de grace later in the season.

Q: I wrote last year about bugs killing my green ash and you suggested to use Neem. I was wondering if it will work without the lime-sulfur because I tried getting it with no luck. I sprayed today and couldn't believe the new holes drilled in the trunks from the outside. A week ago I sprayed and didn't see any holes. The holes are about the size of a small match. I feel like giving up on these trees. (E-mail reference)

A: What you are looking at could be holes from the yellow-bellied sapsucker. They are active at this time of year punching holes in trees to get them to bleed to attract insects, which they then enjoy as a meal.

Q: I noticed a couple requests for sources to purchase fernleaf peony and thought you might like to know that I found another. They can be purchased online through www.paradisegarden.com. (E-mail reference)

A: Thank you for the tip! I'm sure many of the readers will appreciate having this information.

Q: Do the new white plastic milk jugs allow the sunlight to pass through like the clear plastic jugs did? A gardener cuts the bottoms out and uses them for frost protection. He doesn't take them off every day and would leave them on for a long period of time. (Ellendale, N.D.)

A: The white plastic milk jugs will diffuse the sunlight where the clear will not. It will actually be better for the plants as the diffused light cuts down on shadows, maximizing light all around the plant resulting in better growth.

Q: Do you have any idea at what temperatures (lows) spring bulbs can survive? I'm wondering what will happen to them if they freeze. Will it kill the bulb? Also, we have patches of some type of grass showing up in our bluegrass lawn. The blade is extremely fine (almost like a newly seeded bluegrass), is slower to green up in the spring (so can easily be spotted right now), is a brighter green than the bluegrass once it gets going, and is very matted and tangled after the winter (rips out in a mat if we try to rake it.) I noticed it about two years ago and there are more areas every year. Any ideas as to what it is and what to do about it? (Aberdeen, S.D.)

A: Spring bulbs will tolerate anything that Mother Nature will throw at them right now -- snow, freezing rain, temperatures down to the mid-teens, etc. Don't bother covering them. It sounds like it might be bentgrass that is getting started in your lawn. If you are a golfer or live near a golf course, that's my best guess at this point. If that doesn't fit the bill, then my next best guess is nimblewill, which resembles bentgrass in appearance and would be sprouting and growing now in your area. Either get it raked out or spot killed with Roundup.

Q: If a chokecherry has black knot on a main trunk of the tree, and the infected area is cut out down to healthy wood, should anything be applied to that area? Also, do you recommend any fungicide on these trees after removing diseased areas? (Hettinger, N.D.)

A: Lime sulfur can be used after the knot-infected branches have been removed, providing the tree is still dormant. Lime-sulfur is getting increasingly difficult to locate in the retail trade. Caviler is then sprayed if the lime-sulfur is not available, once while the tree is still dormant, a second time when the buds are at the pink stage, at full bloom, and three weeks after full bloom.

Generally if the disease has progressed to any significant degree, one is better off taking the tree down and replanting with a different species.

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