Hortiscope

October 12, 2006

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We will be landscaping our yard next year and replanting grass. What do you know about amazoy zoysia grass? Is it too good to be true? Would you plant it in your yard? If not, what type of grass would you plant? Thank you. (Gackle, N.D.)

A: In Gackle or anywhere else in North Dakota, forget about zoysia grass. It will live (barely), but not thrive. We used to plant it in Texas, but even there, with the heat and rain, it was slow to establish. Zoysia grass usually goes dormant when temperatures start dipping below 40 degrees. It will remain dormant until the temperatures rise and stay in the mid-70s. I have had plenty of complaints about zoysia grass, but no one has ever called and told me how wonderful it is! Frankly, I wish it lived up to its hype because the zoysia turfgrass systems I have seen in the south are beautiful carpets of green.

Q: I have a question about the timing of overseeding a lawn. I put down Ortho Weed-B-Gone Sept. 1. The label said to wait three weeks before planting seed. I would like to overseed with Kentucky bluegrass around Sept. 21, but is that too late for effective overseeding? (Pierre, S.D.)

A: It is not too late, but if you don't follow the label and plant too soon, the residue will keep the seed you put down from germinating. Take heart because sometimes the month of October is best for growing grass. It only needs to get started.

Q: I love hydrangea plants! I purchased four plants in the early spring. At first, the plants did not do well outdoors, so I replanted them in large containers and put them on my patio on the south side of my home. They receive sun and shade from a privacy fence to the west. They now have beautiful, full green leaves. They retained the flowers that were not lost in the early spring. The flowers have turned a lovely shade of green and rust. They were purple and pink. Should I bring them indoors for the winter or should I plant them directly in the soil on the southeast side of my home (only place left for plantings)? What preservation techniques do I use? Will the color return in the spring or summer when they bloom? (Rochester, Minn.)

A: Plant them where you want and cut them back to about 12 inches. But since you live in the banana belt, you don't want to do that until the end of September or early October, after a couple of good frosts.

Q: I enjoy your articles. I have lots of diseased elm trees that need to be removed, but I am confused about what I should plant in place of the elms. The new plantings would be used as a shelterbelt, so I want some fast-growing trees that have a long life expectancy. Will a row of lilacs and a row of cottonless cottonwoods work? I’ve had good luck with them before. I am short of space, but I could squeeze in another row. Is the cottonless cottonwood the same as a poplar or is that a different tree? I read that cottonwoods also have disease problems. (e-mail reference)

A: Thanks for the compliment! Any tree is going to be subject to pathogens and insects. Some are more prone to problems under certain conditions than others. If you have had good luck with cottonless cottonwood (poplars) and lilacs, then continue to use them.

Q: I have a small raspberry patch that has developed mold on the raspberries. Can this be treated and how? (e-mail reference)

A: Your problem is probably mildew. At this point, it is too late to do anything about it. Next year, put down a preventative spray as the flower blossoms drop off.

Q: I bought two schefflera plants. We moved shortly after that and I placed them at the ends of my sofa. One is doing well, with very little loss of leaves. The other must be infected with some type of scale insect. Using a magnifying glass, I can see some small scales on the underside of the leaves. The leaves also have black spots that spread and then the leaves fall off. I've also had a few leaves fall off that didn't have the black spots, but they had a tiny scale or two on the underside. I have taken this plant outside twice and wiped the leaves off and sprayed it to cover the mites. It stopped for a while, but has started again. I'm afraid if it doesn't get help soon, I'll have to throw the plant away. What should I put on it to stop these scales and black spots from happening again? I'd appreciate any help you can give me. (e-mail reference)

A: Get a systemic insecticide for houseplants from your local garden center. This is translocated throughout the plant and will kill these tough insects as they feed on the plant. You should move the plant outdoors to do the application. Be sure to follow label directions.

Q: The leaves on my azaleas are turning silver and black on the underside. I think the problem is mites or lacebugs. I have used soap, an insecticide and Bayers. However, I am very late realizing this problem. Everything I have read says to start using these products in the early spring or summer. Is there any hope for the bushes? If I am going to loose these 25 plants, I want to take them out and replant this fall. (e-mail reference)

A: Based on what you have told me, I'd say go ahead and take them out and replant. Next time, begin monitoring the plants as they leaf out in the spring and through the summer to catch anything that might be getting started.

Q: My husband and I just built a home north of Bismarck. Our well water is salty and rural water is not available. We are contemplating planting grass in the next couple of weeks. Do you have any suggestions about the type of grass or grass mix that would work? I’ve heard that if you water with salty water, you have to water more to flush the salt out of the soil, but eventually (after a couple of years) it will kill the grass. I also am worried about ruining my garden plots. Will the salt water inhibit germination of the grass seed? Is there a counteracting mineral we can add to lessen the effect of the salt? A totally unrelated question: What is a good, fast-growing, long-living tree to line my long gravel driveway with? Your knowledge and time on the radio are greatly appreciated! (e-mail reference)

A: Thank you for your very nice words! I have a couple of approaches for you to consider. You can hook up a reverse osmosis unit that will remove some of the salts and eliminate the problem. The cost of the unit is based on the degree of salt reduction sought and the volume of water required. It won't be cheap, but it will give the most satisfactory results. It will be healthier for your family as well. There is a grass known as alkali grass. The fultz cultivar grows in high-salt locations. It is a common lawn grass in the western part of the state. It isn’t a beauty queen, but it will provide a lawn surface. To answer your other questions: Yes, the moisture level must be closely watched because when the soil dries, the salt concentrates in the soil and can reach toxic levels, depending on the species of plant. The higher the salt content in the water, the slower the germination. Here is a site that you can go to for a selection of trees to consider: www.ext.nodak.edu/county/cass/horticulture/treeshrub.htm.

Q: Do you have any suggestions for killing horseradish that is trying to take over my strawberry patch? I pull the leaves, but the roots remain. (e-mail reference)

A: The only way I know is to get a Dutchman's hoe (oversized pickax) and chop every root out. It may be easier to move the strawberry patch somewhere else.

Q: I just planted my bulbs. Is it OK to cover the ground with large bark chips? I cannot leave the ground uncovered because the neighborhood cats think my uncovered flower beds are their personal litter boxes. In one bed, I used large bark chips and in the other beds I used finer bark mulch. Will either inhibit the bulbs, ability to grow out of the ground? (e-mail reference)

A: Go ahead and cover them.

Q: This spring and summer I noticed small spots in our lawn where something was digging. I assumed it was skunks or raccoons. Yesterday my husband noticed a lot of damage in the neighbor’s yard. The sod is peeled back and the dirt underneath dug up. We live on a farm with four houses. No one is living in the neighbor’s house. Can skunks and raccoons cause this much damage and why? Is it easier to get rid of the animal doing the damage or the thing the animal is digging for? I don't want them to start attacking our lawn. Any insight you have on this situation would be greatly appreciated. (e-mail reference)

A: That is typical of skunk damage. They are looking for and probably finding grubs, the larval stage of scarab beetles. Get rid of the grubs with a soil insecticide and the skunks will go somewhere else. You also might try trapping the skunks (good luck!) and moving them elsewhere.

Q: We have an area in our yard that was once a feedlot, so what's been growing there since we've moved in is a lovely crop of weeds. We haven't had time to deal with it, so we've just been mowing the weeds. At least it's green, except for a few spots that stay dirt. We'd like to seed it to grass this fall, but I'm not sure on the best way to do it using the least amount of effort. The terrain isn't perfect and there are a lot of rocks. If we were to dig it up, we would be spending the next three years picking rocks. We'd rather not do that and we really don't have the equipment. Do we need to use Roundup on the weeds? How long do we have to wait before we can seed after using Roundup? What kind of seed should we use? What is the magic date to seed in the fall? I've looked on the Web for answers, but the answers vary. No one seems to equate the answers to living in North Dakota. I should mention that the rest of our four acres that we mow is mostly pasture, but looks good enough for us if we keep it mowed, so we aren't after a perfectly manicured city-type lawn. Thanks! (Lisbon, N.D.)

A: Go to www.ext.nodak.edu/extnews/hortiscope/lawn/lawn.htm and click on renovating. You will find plenty of information there. Yes, kill everything off with Roundup. After it turns brown in about a week, seed into the dead grass. The dead grass will act as a mulch cover. Depending on what you seed, some results could be showing in 10 days to two weeks. Try to get this done as soon as possible. Otherwise, wait until the end of October and do dormant seeding.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu

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