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Don Kinzler, Published May 25 2012

Hortiscope: New sod should eliminate clover

Q: I’m doing some different landscaping and maintenance jobs in my hometown. I’m wondering about how to get rid of white clover in lawns other than using Roundup. I know Speedzone works, but is there any cultural way to eradicate it, such as lightly tilling and then planting grass seed? Would that work or would the clover grow back quickly? (email)

A: During my youth in the horticultural business, clover was considered a good part of a lawn mixture. Clover was 10 to 25 percent of the content. It stayed green no matter how hot or dry it got in the summer. At some point, a chemical company decided to call clover a weed and came up with a potent material called Silvex (not in circulation any more), so clover disappeared from home lawns.

The presence of clover usually is an indication of an underfertilized lawn. Clover seed can remain dormant in the soil for 20-plus years and then germinate when the environmental conditions are right for growth.

Without using chemicals, there only are a few ways of getting clover out of the lawn. A thatch rake with half-moon blades can scratch the plant out of the ground. After that, reseed, fertilize and mow high. You can use a monofilament weed eater to whip the tops off the plants. It will leave the roots there, and the roots will resprout.

However, we found that if you can get a slab of sod and get the homeowner to get it established and rooted, it usually will take care of the clover. This may not work with old, well-established clover plants. Repeating the battle eventually will weaken the plants, so with persistence, victory will be yours.

Q: I have a healthy dwarf orange tree. The tree flowers and many tiny green buds form. They grow to be a quarter-inch across and then they all fall off. How come? (email)

A: It is the lack of sufficient plant fertilization. Get a small oscillating fan or an artist’s paint brush to dust the pollen onto the pistillate (female) part of the flower to get fertilization accomplished. Being an indoor plant with no air movement or insect activity, pollination doesn’t take place. If that doesn’t make small oranges, then the variety you have was bred as a sterile (nonfruiting) tree.

Q: My question involves a soil sample test report that I got from NDSU last winter. It tells me not to modify my soil other than to add a bit of nitrogen.

However, the soil pH is 7.7. Everything I thought I knew about soil pH suggests that number is too high. I am used to working with pH levels in the 5.5 to 6.5 range. I hate to mess with success, but I want to improve on that success if I can. I raised a tomato last summer that was 11 pounds 15 ounces. Should I mess with changing the pH? (email reference)

A: A pH of 7.7 is high but not out of the range of being able to grow crops such as you have so ably demonstrated with growing a near bowling ball-sized tomato.

A pH above 7 is fairly standard for most of the state, so we’ve gotten used to seeing readings that high or higher. A pH lever higher than the middle 8’s would start to beg the question of what can be grown at that level without a major soil modification. Leave everything well enough alone and you’ll be able to enjoy a crop of tomatoes like you did last year.

Q: I raise Yukon gold spuds in my backyard garden. This spring, I found the hollowed-out potato shells that you can see in the attached pictures. What do you think did that? For the first time in 11 years, squirrels ruined nearly all of my sweet corn last year. I tried a few repellants, but that didn’t seem to help. The squirrels sit on my neighbor’s fence and jump onto the stalks. What do you suggest? Should I use live traps, netting or a shotgun? (Fargo)

A: Go to http://tinyurl.com/

csqwx2z for a publication that will explain hollow heart, which is apparently what your potato crop is suffering from. As for the squirrels, all would work except shooting because it is not allowed. I’d suggest a live trap before the corn harvest starts. Get some corn food for the larger birds to feed on and your neighborhood squirrels also will show up. Then get a live trap and place the corn inside. The squirrels will show up and get trapped. You then can move them to the country.

Q: How important are bees to a Juneberry? (email)

A: How important are Juneberries to bees? That is the better question. Being early bloomers, the Juneberry flowers are a good source of nectar and honey for the foraging bumble and honeybees. A Juneberry can get along just fine without bee activity but would have a much lower fruit production without their input.

There also are other insects that get involved in the pollination of flowering shrubs and trees. However, none are as important as the bees.

Q: A couple of weeks ago, you had an article about Sucker-Stopper RTU. Is this product just for use on trees? What can I use to stop seedlings from coming up from the roots of trees? I was afraid to use Roundup because I figured it would follow the root system and kill the tree. Please advise what to do because I’ve been snipping the seedlings at ground level when they come up. (email reference)

A: Go ahead and use Sucker-Stopper RTU on root suckers. After you cut the suckers back as far as possible, give the cut surface a shot of RTU. After that, there will be no more suckers at that location for the balance of the growing season.

Q: We have a flowerbed that is 15 feet away from a large cut leaf weeping birch tree. The bed contains perennials and tulips. If you dig 4 to 6 inches into the ground, it is a solid mass of roots. I am unable to till the bed because of the perennials. I am wondering if there is any way to control the tree roots. You can tell the plants are hurting because of the tree roots. If I destroy the bed, I am assuming the roots will be back shortly. Thanks for your response.

(Napoleon, N.D.)

A: I have the same tree and problem. We cut the roots out that are in the way of our intended planting site. We fertilizer with Miracle-Gro on a monthly basis and the tree, bulbs (daffodils and tulips) and herbaceous perennials all seem to be doing fine. I really don’t suggest tilling the area because the damage would be too extensive to the roots of the tree and make it a target for a bronze birch borer attack.

Q: Though I am not from North Dakota (south of Green Bay, Wis.), I am hoping you can help me. What a wealth of information you have made available on the NDSU website with your question-and-answer format. It is much appreciated. You are obviously an expert among experts with your knowledge. I am seeking information on how to establish for sale proprietary trees from a new variety. My situation is that I have several hundred wild apple trees on my 38 acres. I have cataloged and marked about 12 trees with fruit that is unique and tasty (one has a hint of concord grapes after an October frost). I know the history of my property and have aerial photographs as far back as 1939. From the photographs, I have determined that the apple trees started growing sometime between 1940 and the present time. Most of the growth has taken place in the last 25 to 30 years. The lady I purchased the land from in 1985 told me that she and her husband lacked feed for their cattle during a dry year, so they fed apples to the cattle.

However, she wasn’t sure where the apples came from (not from the farm). This took place sometime in the late 1940s or early 1950s. The cattle grazed the hilly nonfarmable portions of the 38 acres. I believe that cattle droppings are the source of the apples. The 12 trees I have marked have tasty and good-sized apples. They store well in a refrigerator and seem to have natural resistance.

My immediate goal is to propagate the 12 to ensure continued lineage. I have had limited success with grafting, so I am going to try air layering this year.

Because the trees are surviving on their own accord, I am convinced that the root systems are hardy enough without using root stock grafting if the air layering is successful. However, do I need to do root stock grafting because I will be producing a large number of saleable trees? Any tips would be appreciated, as well as guidance on establishing trademark/proprietary protection. Also, apple pies made from a mixture of seven of my favorite apples are out of this world and cannot be duplicated anywhere. Every mouthful tastes slightly different. Springtime blossoming is awesome, too. (email reference)

A: First, thank you for your very flattering remarks because I don’t consider myself an expert. I’m just a student learning more and more with each passing day. It sounds like you’ve got a gold mine of apples on your property. Asexual propagation is the best way to go to increase their numbers. I encourage you to contact the University of Wisconsin Extension Service for assistance. Go to http://www.uwex.edu/ces/cty/ and click on your county to get in touch with an Extension agent. He or she should be able to hook you up with a specialist at the university who can assist you with getting the budding/grafting procedure rolling or recommend other propagation techniques that would increase your stock for sale quickly. The College of Agriculture (or whatever name it goes by) at the university should be able to provide you with guidelines for patent procedures. Your description of the apple pie sounds very tempting. Perhaps a local bakery would be interested in contracting with you to make pies to sell to the public. When I had my small raspberry farm in upstate New York, I did just that, so I really enjoyed the fruits of my labor.

Q: My daughter bought a home in Bismarck with an old lilac tree in the middle of the front yard. It has not been taken care of in a long time and there are many dead areas on the tree. She has always loved weeping willows and would like to plant a good-sized one in her front yard. The only logical place to put the tree is right where this old lilac is located. How does she go about removing it? Can it be dug out successfully and the willow put in the same location? Will runners from the old lilac reappear? Thanks for your help. (Bismarck)

A: The lilac that has been occupying the same location for a number of years may require a chain attached to a pickup to pull it out (done that) or a very determined individual with a Dutchman’s hoe. The remaining roots will sprout with suckers that can be controlled by using a broadleaf weed killer. She then can plant a weeping willow in the same location. However, beware that willows often go beyond the expectations of the owner as far as size and messiness, so tell her to be sure that this is the tree she wants!


To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or email ronald.smith@ndsu.edu