April 29, 2004

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We had a lot of lawn winter-kill this past season. What is the best way to treat these areas and what products would you recommend? (Fargo, N.D.)

A: Rake the surface with a leaf rake to get the grass to stand up and the crowns to warm in the spring sunshine. Most grasses will recover, so be patient. As the soil warms, the grass will come out of its winter funk.

Q: My daylilies are up about three inches. Are the cold night temperatures affecting them? Should they be covered? (E-mail reference)

A: Daylilies are as tough as an Alaskan grizzly. The cold temperatures we have remaining this spring should not hurt them.

Q: We have two small bushes in front of our house that get clusters of small white flowers on them. We want to move them to another area in our yard. When should we move them and is it possible to separate them to make more bushes? (Oakes, N.D.)

A: Whatever they are, divide and move them now before any new growth begins.

Q: My rose bushes bud, but only a few bloom. They then turn brown and never fully open up. (E-mail reference)

A: It sounds like a very common disease known as botrytis. Try spraying them with a systemic fungicide this spring as new growth begins.

Q: We have four cottonwood trees in our back yard. They are great shade trees and we love them. Like everyone else I hate the cotton that comes off the trees. A local green house owner suggested using a product called Florel to cut down on the cotton. We sprayed it on our trees last year and cut the cotton production down by 85 percent. The only side effect I have seen are fewer leaves on the trees, but this could be caused by the drought we’ve been having. (E-mail reference)

A: Florel supposedly reduces crabapple fruit production for those who do not want so many messy fruits, but this is the first I have heard of it being effective on the cotton that comes off the trees. I was curious so I looked up the label and sure enough it is labeled for cottonwoods. I know a lot depends on timing, so apparently you got it just right last year. Let's hope you are as successful this year!

Q: I have a gardener that thinks you can plant hybrids, and if you save the seeds and plant them next year, they will revert back to their original variety instead of being a hybrid. I don’t think this is possible, but I have experience with animals, not plants, so I am just double checking to make sure. (Carson, N.D.)

A: The gardener was right. Hybrids are bred to produce a single generation with particular quality characteristics, such as flower or fruit size, disease resistance, height, time of maturity, flavor, etc. The seeds from those hybrid plants will be sterile or be a wide range of the parental line that went into making the hybrid.

Q: The leaves of tulips and lilies are spotted with a rust colored, small, circular dot which extends to the flower petals. Last year I planted 100 tulips and only six returned. The leaves of the tulips are not only spotted, but also deformed and twisted. Nothing appears to be wrong with the bulbs. Could this be a late frost problem? (E-mail reference)

A: I doubt it is a frost problem. Tulips are one of the coldest tolerant bulbs on the market. They can grow and bloom even if there is still snow on the ground. My guess is you had some kind of herbicide residue in the soil when you planted them or had some herbicide drift. The fact that the bulbs themselves appear sound is an indication that the problem isn't likely biological.

Q: We built a new house last fall and are about to have the final grading done to prepare for seeding the lawn. What is your opinion on hydroseeding? It seems expensive. Do you get a good lawn? What is the best grass seed mixture for this area? (Moorhead, Minn.)

A: It is more expensive than do-it-yourself, but less than sodding. The results for me have always been good. Our NDSU football practice fields and soccer fields were both hydroseeded with excellent results. A mix of Kentucky bluegrass, fine fescue and some perennial rye works well. The contractor would know which ones perform best. After all, he has a reputation to maintain. Ask to see some areas that he has previously hydroseeded. Remember that no one's grass looks good right now.

Q: I have several lilac trees that are eight to ten feet tall, approximately three feet apart and approximately two feet away from a chain link fence. I would like to get rid of all the grass between the lilacs and behind them up to the fence so that I can plant perennials, put down mulch and not have to mow between the lilacs and the fence. Can I just dig out all the grass with a flat blade shovel or do I risk damaging the lilac’s roots? Is there another way to get rid of the grass and prepare the area for planting perennials? (Minneapolis, Minn.)

A: Spray the grass carefully with RoundUp. Plant your perennials directly into the dead grass and then mulch.

Q: During some recent construction, a beautiful oak of mine was scraped by a back hoe. The result was about an 18- by 10-inch scar where the bark has been peeled back. What should I do to ensure that I don't loose the tree? (E-mail reference)

A: As long as the tree has not been girdled, (bark removed all the way around the tree) it will survive, with some help from you. I would contact a local International Society of Arboriculture certified arborist to examine the tree. They will likely cut back to the attached bark to facilitate healing and provide or suggest a fertilizer. You can do this yourself if you are sure you know what you are doing, but a professionally-trained eye might see other problems with your tree that you are unaware of. If the tree is important to you, it would be worth the investment.

Q: My wife and I have purchased a two acre lot in a rural area. We would like to seed our yard but are really not sure where to begin. I really have no experience and I don't have a tractor. I have contacted 10 different landscapers and have received 10 widely varying prices to have the work done. All the contractors have talked about a rural mix of seed but didn't give us a definite breakdown of what is in the mix. Some have said they would plant it now while others would wait until mid May. It is getting confusing so I need some sound advice. What is the best way to level the yard? Should I till the land? What kind of mix should I use in my yard and would it be better to purchase the seed independently and then have them seed it for me? (Bismarck, N.D.)

A: Have someone with good references do some finished grading. Sow a quick cover of annual ryegrass or oats to help sequester weeds and prevent wash-outs from the rains. After mid-July, have everything killed off with RoundUp, and mow the dead material short, collecting the clippings. Sow into the litter left behind an all-purpose mix containing something like park Kentucky bluegrass, creeping red fescue, fairway crested wheatgrass, perennial ryegrass and Dawson red fescue. By doing it late in the season, you will get quicker germination and have fewer weed problems.

Q: I have a dieffenbachia plant that I've been taking care of for six to nine months. For the past three to four months I've noticed a fungus growing on it. There are also small gray balls in the dirt which might be spores or egg sacs. The gray balls are filled with fluid. When they are squished, they pop and ooze a clear fluid. I have been spraying Schultz insecticidal soap on the plant for the past two weeks, but it doesn’t seem to help. (E-mail reference)

A: I have no idea what the gray balls might be. Your photo clearly shows a mealybug infestation. I would suggest soaking a cloth in rubbing alcohol and wiping the leaves completely on both surfaces. Whatever those balls are on the soil surface, remove them to be on the safe side.

Q: I have a lilac bush growing next to my house. I want to get rid of it and build a deck this spring. Is there a way to kill it permanently without having to dig it up? What is the easiest way to dig it up if that's the only answer? I understand there is quite a root system under the bush. (E-mail reference)

A: Get a shrub and brush killer herbicide and spray it on the plant. That will do it, I assure you. If you want to make sure, after the plant appears dead and you cut it out, paint the remaining stub with the herbicide. It should translocate and kill the entire root system.

Q: We have a very large box elder tree in our yard. The base of the tree has tons of suckers coming out of it. Should I prune them off or will that hurt the tree? (E-mail reference)

A: The proliferation of suckers is usually symptomatic of something going wrong with the tree such as water table change, compaction, borers, drought, disease or some other abiotic damage. If the tree is important to you, you might want to have it checked out by a professional ISA certified arborist. Pruning the suckers out will not hurt the tree, but you should look into why it is suckering so much. This is usually a prelude to the death of the tree in the next year or so.

Q: My neighbor would like to try growing some lingonberries, but I think lingonberries need acidic soil. Should she work in a bunch of peat moss to make the soil more acidic? Is there something else she should do? (E-mail reference)

A: Use plenty of sphagnum peat and fertilize with an acidifying fertilizer. There are plenty on the market. Aluminum sulfate is the strongest acidifier followed by ammonium sulfate.

Q: We have a large, I think, white oak tree in our front yard. About a year ago, we thought lightning struck it. Not long after, the bark started to peel off. It did not grow leaves last year, but this year it is. Do we need to cut the tree down? (E-mail reference)

A: From your description, lightening most likely did strike the tree. The initial jolt probably cooked the leaves and most of the main trunk cambium and root system. The tree is now leafing out with carbohydrate reserves in the limbs. It is very likely the leaves will be undersized and die prematurely. If this doesn't happen, and the tree leafs out normally and produces new growth, something else happened. I would advise you to have an ISA certified arborist examine the tree. This is important because of its location. It could cause extensive property damage or personal harm if it should fall.

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: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu

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