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Don Kinzler, Published June 11 2010

Does needle cover damage grass growth?

Q: The grass around our arborvitaes used to be beautiful. This spring, I noticed the grass is very thin and the winter winds blew a lot of the dead needles out of the trees and onto the grass. Can these needles damage the grass? The grass where the needles didn’t fall looks normal. If the needles do affect the lawn, what can be done other than trying to remove the majority of the needles? (e-mail reference)

A: A number of causes can contribute to grass decline next to any mature woody plants. It could be water and nutrient competition from the roots of the arborvitaes that are integrated with the grass roots. Depending on the orientation, shade from the arborvitaes would impact turf grass quality negatively. There must be millions of situations across the country where attractive turf is adjacent to arborvitae plantings. I would encourage you to rake up the needles, have your entire lawn core aerated, power raked and fertilized and do some overseeding.


Q: My raspberries are taking over my garden. Can I transplant them into a box or something similar with a bottom so the roots don’t keep spreading across the garden and surrounding lawn? (e-mail reference)

A: Where do you live that they are that aggressive? Yes, you can go ahead and box them up to keep them confined. They just happen to be weedy biennials that produce deliciously healthy fruit! Annual maintenance would work to keep them from spreading, unless you have too many to look after.


Q: I have a box of plant food in my garage that has been there for approximately 10 years. Is it still potent enough to use or should it be tossed? I would like to try to grow green peppers this year. However, I read they require a great deal of phosphorus. Can you tell me if this is true? If so, what do you suggest in the way of plant food for peppers? (Fargo)

A: The material will be usable. However, it probably is caked together, which will require a hammer or some other means of breaking it up prior to spreading.

While peppers will use phosphorus, they do not need any more than any other fruit-bearing plant. Go ahead and grow them. Unless your soil is almost pure sand, there should be ample phosphorus to grow a decent garden of peppers.


Q: I just purchased luscious and parker pear trees from a nursery. I didn’t know what varieties to get, so I bought what was recommended. After doing some research, I found that the luscious is pollen sterile. Does this mean the parker will pollinate the luscious, but the parker never will produce fruit because the luscious is pollen sterile? I don’t have any other pear trees. Would summercrisp have been a better choice than the luscious? (Strasburg, N.D.)

A: The consensus in the literature is that you would need a third tree, such as a summercrisp, to get fruit from all three. Luscious is known to be quite susceptible to fireblight, so you might want to reconsider keeping that one.

Trade it for a summercrisp, assuming you haven’t planted it already. I gave up attempting to grow pears in my backyard in Fargo more than 20 years ago because of fireblight and chlorosis problems. It was not worth the effort.


Q: I have three bleeding hearts planted on the north side of my west entryway.

The plants are getting too big for this area, so they need to be moved. When is the best time to move them? Can I plant them on the west side of my house? They wouldn’t get any direct sunshine until noon or so. After that, they would have direct sun for four to five hours before the area becomes shaded by my neighbor’s trees. Would this be an ideal location or should I think of another spot? (e-mail reference)

A: Without knowing where you live, I would say that the west side location should be OK. However, the higher afternoon temperatures may shorten the bloom time of the plants. They can be moved when they are finished blooming or have gone dormant.


Q: I have a question about my spring cactus. Right now, it is blooming beautifully! I live in Texas and this past winter we had several hard freezes.

Not knowing any better, my poor cactus was left outside. Now it has very brown and leathery base growth. I am not sure if I need to remove that part of the cactus or just let it grow out. The new growth is healthy and doing fine. I am baffled, so any help would be greatly appreciated. (e-mail reference)

A: That is probably superficial damage and the plant should callus it over as it continues to grow. Monitor it to make sure a fungal rot doesn’t get started.

Glad to hear it is blooming so beautifully. Enjoy!


Q: A generous friend gave me a rose bush. The picture on the package shows a big fancy lavender floribunda rose called angel face. It is rated for zone 5. Does it have a better chance of surviving near the house foundation where it gets really hot and dry in the summer or near the clothesline where the rest of my rose bushes are planted? Personally, I don’t think it will survive the winter in either location. (Hazen, N.D.)

A: Don’t be such a pessimist. Give it a chance with your other roses near the clothesline. Plant it deeply enough and give it copious protection going into the winter.


Q: I have a climbing rose that I found at an old house. At the time, it had small pink roses on it and it climbed. It looked really good after I planted it, but then the green leaves started curling up and turning brown. After two years of fighting with it, I decided to cut it off and get rid of it. The next year it came back beautiful and green and climbed across my lattice. Then it did the same thing. I have looked for bugs and cutworms and even sprayed it with Ortho.

Please help if you can because I am tired of trying. (e-mail reference)

A: I have no idea what caused this problem. It could be that the soil is contaminated in some manner. When the roots come into contact with that material, such as pesticide residue, you will have problems. Cut some frustration out of your life and give up trying to work with this particular rose.


Q: I have a bunch of cottonwood trees in my backyard. As always, they produce the sticky pods and then the white cotton seeds. They stick to my dog’s paws, so he tries to get them off and usually ends up eating them. Are they bad for him to eat? Could they hurt or even kill him? He seems to be feeling sick lately and the pods are the only thing different around here.

(e-mail reference)

A: I would suspect that these are the cause of your dog’s nausea. Try to get the seeds raked or vacuumed up as they fall or at least keep an area clean where the dog will be. They should be done dropping their mess in another week or two.


Q: I have a red oak that is at least 30 years old. During a two-week period, the bark dropped off (in chunks) at an accelerated rate. However, the foliage is abundant and appears healthy. (Hoschton, Ga.)

A: This could be from a surge of growth and is a normal exfoliation of mature bark. If there is no evidence of borer activity, such as sawdust emerging from pencil-sized holes in the trunk and the tree is otherwise healthy, I don’t think you have anything to worry about.


Q: I have two goldcot apricot trees. Both were planted in 2000. One year, one of the two had a couple of flowers and then the whole tree froze to the ground. It came back from the roots and is as tall as the other tree. How many years should I wait for the trees to bloom and bear fruit? Is there such a thing as a nonproducing tree? I bought the tree out of a catalog and live in southeastern South Dakota. (e-mail reference)

A: Apricots are a fickle species for bearing fruit. Their timing for flowering often is contrary to what Mother Nature has in mind. Their buds are very sensitive to low temperatures. If the buds are softened up by being teased out of winter hardiness too soon, they will be killed. You could go another three to five years before you see any flowers, let alone fruit, or you could get more fruit than you can use. You must be a very patient person to wait this long for a reluctant apricot tree to bear fruit. I’d suggest getting rid of them and going to a local nursery or garden center to get fruit trees. They would at least be adapted to your zone.


Q: I’ve noticed some letters to you from New Jersey and New Zealand. Would you take a question from northern Idaho? If so, I have a hybrid poplar tree that is 10 to 12 years old. It is sending out suckers all over the county (really, only my yard but it’s starting to feel like the whole county). I’ve read your column on poplars and will get the Sucker Stopper if need be. However, the larger concern is a small maple tree I planted that is about 5 feet away. It was a freebie sent with some other plants I ordered some years ago. I didn’t think it would live, but I stuck it in the ground anyway just to give it a fighting chance until I could move it. I never moved it. It lived in spite of me. Will it survive with the poplar so close? The poplar is the only shade tree around my house. However, I’m getting the impression they’re pretty much a garbage tree, so I’m wondering if I should sacrifice it to give the maple a better chance for survival. (Princeton, Idaho)

A: This has to be one determined maple to be growing that close to a mature poplar! If it was up to me, I would get the poplar professionally removed and give the maple free rein to develop to its full potential. While it will survive, it never will thrive. Also, the branches that the poplar so freely drops might end up damaging your maple. Be sure the company taking down the poplar is aware that the maple is not to be mistreated during the removal.


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 e-mail ronald.smith@ndsu.edu.