Hortiscope

August 10, 2006

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I have some cuttings from an African violet plant. Should I stick the cuttings in the soil or lay them on top and then cover them with soil? (e-mail reference)

A: One of the easiest ways to root African violets is to stick the leaf petiole into a media that is 50/50 sand and sphagnum peat moss. If you lay the leaf on the surface, notch the veins with a knife and make sure the cut is in direct contact with the surface.

Q: I planted 10 blue spruce trees this spring. I followed the planting instructions and tips given by the salesperson. I mixed peat moss in with the loose soil, planted them with the ball even with the ground and put a layer of mulch around them. After planting the trees, I watered thoroughly and have been watering the trees once a week. Four trees are doing great and developed new buds. However, four have turned brown and lost their needles from the ground to the middle of the tree. Are they dead? Can they be saved or do I dig them up and start over? I have a one year warranty on them, if I can just find my receipt. What did I do wrong? (e-mail reference)

A: From your description, you have done nothing wrong. I suggest going back to the nursery where the purchase was made and see if you can find the clerk who waited on you. Hopefully, some replacement arrangements can be made.

Q: I can't seem to find on the Web how and if I can split my bleeding heart plant. It’s such a beautiful plant and I don't want it to die. (e-mail reference)

A: Bleeding hearts can be divided in the fall or early spring. Use a straightedge spade to do the job.

Q: I have a walnut tree question. My parents have a large black walnut tree that I used to play on as a child. For sentimental reasons, I would like to plant a tree from one of the walnuts. Is that possible? What do I need to do? If this is not possible, can I take a small shoot or branch from the tree and get it to grow as a seedling? (e-mail reference)

A: Growing from seed is the way to go. The biggest problem likely will be with squirrels in the neighborhood. They might be watching your planting activity and dig them up for themselves. This fall, pick up the nuts that drop to the ground. Wear gloves because the stain will be difficult to get off your hands for days, if not weeks, when you remove the green, outer husk. After removing the outer husk, plant the hard nut where you want the tree to grow. The winter temperatures will stratify the seed, so any viable seed will grow the following spring.

Q: I have 40 acres along the Des Lacs River. We have a weed we have called foxtail, but it does not have a cone shape. This weed has a fan-shaped head while maturing and then becomes a wide, spread-out head that is a danger to animals, especially dogs, because they may inhale the fine shafts. Is this a type of foxtail? What is the best herbicide to kill this weed and what application timing is best? (Burlington, N.D.)

A: I think what you are describing is barley foxtail. Go to www.ext.nodak.edu/extpubs/plantsci/landscap/h1009w.htm for my publication on weed control. Foxtail is included in the publication. Pre-emergent materials commonly found on the market are the best means of control, which needs to take place in the early spring.

Q: I planted a strawberry garden two years ago. The plants produce strawberries, but the berries are the size of a dime. I do have creeping jenny in the garden. Is that why the strawberries are so small? I do water the plants, but don’t know what kind of fertilizer I should use. What should I do to make them bigger? Thanks. (e-mail reference)

A: Strawberries are very jealous of any competition. If you have creeping jenny, it is small wonder the strawberries are undersized. I'm afraid your only alternative is to start new in a different location or by wiping out everything, especially the creeping jenny, and then replanting next spring. Go to www.ext.nodak.edu/extpubs/plantsci/hortcrop/h16w.htm and download the publication on strawberries. Strawberries respond well to fertilization twice a year. Fertilize in early spring before flowering and right after harvest. Use a 10-10-10 fertilizer broadcast over the plants and then water in.

Q: Can you tell me where I might be able to find the product "Grass Killer" by Hy-Yield that you mentioned in your article last week? I have a problem with grass in my raspberries and strawberries. (e-mail reference)

A: Try the "Marts," such as Wal-Mart, KMart and Target. Also, all the local nurseries should have this or a similar material. Look for anything that has sethoxydim as the active ingredient. That's the stuff that works.

Q: We have some growth on the leaves of our maple trees. The growth looks like pine needles sticking out of the leaves. Is this bad? Is there something we can do? We have two of these trees at one end of our yard and one at the other that have the same problem. We also have a different type of maple in our yard, but those maples don’t have this needle thing going on. I would like to know if we need worry or if there is a possibility we may have to cut the trees down. (e-mail reference)

A: This is a nipple gall that is caused by the harmless feeding of a mite early in the spring as the leaves are unfolding. The mites are about the size of a period at the end of a sentence. The mite feeding has a growth regulator effect on the developing tissue. The galls will not harm your trees, but do have a cosmetic impact. The galls likely will disappear next year. Spraying is not recommended because natural predators usually will keep them under control.

Q: I have a huge dog pen that I filled with gravel. The pen has been taken over by thistles. I've tried pulling them out and have used Roundup and bush killer. The pen stayed clean for about five days. Is there any way to control the thistles? Will a black tarp under the gravel help? I have 16 bags of weeds sitting in my barn because the city I live in won't take the weeds from the curb, so I have to take them to the dump for $10 a load. I'm going broke and they are driving me crazy. Any suggestions? My neighbors keep telling me to get rid of them before they flower. (e-mail reference)

A: If you cannot afford to hire a professional pest control operator to apply a restricted-use herbicide (the cost is about $50 to $75), then your only alternative is to shade them. Get a black tarp and lay it over the area and seal it with cinder block or stone. Leave it there for at least two weeks in the hot sun and see if that cooks them. They are tough to get rid of once established because of their root and rhizome system. I really think the best alternative is to contact a professional exterminator.

Q: I have a question about our green ash trees. They were planted in the spring of 2005. They developed lesions on their leaves last spring and this year. The leaves tend to curl and turn yellow. Last spring I contacted the forester in Jamestown, but he didn’t seem to know what the problem was. I am coming to Fargo, so I’m wondering if I could bring you a sample. If you are not available, could I drop the sample off with someone? (Edgeley, N.D.)

A: This could be ash anthracnose, but to make a positive determination, you need to send a sample to the plant lab in Waldron Hall at NDSU. Better yet, bring it with you when you come to Fargo. The lab diagnostician is Kasia Kinzer. Her phone number is (701) 231-7854.

Q: I heard that if you cut down dianthus after it is done blooming, it will grow and bloom again that same summer. Is there any truth to that story? (Valley City, N.D.)

A: Yes.

Q: I have a cottoneaster hedge that is flourishing. The only problem is it has adopted my configuration, which is thick at the head and wide at the bottom. Would now be a good time to shape it properly? (e-mail reference)

A: You can do some light shaping now, but if extensive shaping is needed, the best time is early spring. Do it while the hedge is still dormant and then work with the succulent new growth that follows to get the shape you desire.

Q: I planted a row of squash that is now rotting at the bloom end. What should I do and what is causing the problem? What do I need to do to prevent this from happening again? (e-mail reference)

A: The problem is blossom end rot on squash. This is the same problem that occurs with early fruit set of tomatoes and peppers. The problem should disappear as the season moves on and other fruit is set. It is caused by sudden changes in the water supply, such as going from very little water to a sudden abundance. It also can be caused by vigorous cultivation. This damages the roots and limits their ability to absorb nutrients. This results in incomplete cell formation at the end of the fruit, cell tissue collapsing and then secondary organisms moving into the fruit.

Q: As I was mowing my grass, I noticed that under my apple trees there are small webs in the grass. I have not noticed them before. Do I need to spray the trees? The trees are heavy with apples. I need to cut some of the branches off near the bottom so I can mow. Can I do this if I treat the wounds? (Blanchard, N.D.)

A: The webbing could be the start of a fungal disease on your turf, but is generally nothing to worry about. Keep the grass mowed and collect the clippings when you note the fungal webbings. You can cut the lower branches off the apple trees, but you do not need to treat the cuts. In fact, treating the wounds inhibits good healing.

Q: We sprayed our garden with Ortho Weed-Be-Gone last fall. Consequently, some of the onions, tomatoes, potatoes and carrots did not grow. Will this spraying affect the eating of the rest of the vegetables? I know the weeds did not come up until this past week. I would appreciate your knowledge on this matter. (e-mail reference)

A: I don't think this herbicide is cleared for vegetable garden weed control. Technically, you are not supposed to consume the vegetables for safety reasons.

Q: I read the article about not putting grass clippings around garden plants if I have used weed and feed. Does this rule apply all summer or just the first couple of cuttings after applying weed and feed? (Starkweather, N.D.)

A: If you can wait until after three cuttings, there should be no herbicide residue that could cause harm to your garden plants.

Q: I bought and transplanted a weeping birch last spring. The tree did great, but this year it appears that the top half is not producing leaves. I thought this was how it grew. I was going to trim the nongrowing limbs, but the buds and limbs appear to be alive. I am at a loss! (e-mail reference)

A: This could be evidence of the start of a bronze birch borer attack. Check the branches to see if there are any d-shaped holes or swelling under the bark. The borers can kill a birch tree a limb at a time. If the borers are present, prune the infected limbs and get someone to apply a protective insecticide.

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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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