NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5665
May 28, 1998
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Enclosed is a limb off my Canadian cherry tree. I had the top trimmed off recently and there were several of the branches with this growth on them. We looked the tree over carefully and think they have all been removed. The tree looks healthy and is full of blossoms. It was planted six years ago. (Mayville, N.D.)
A: This is an outstanding example of black knot fungus that has been running almost rampant in our region over the past few years. High moisture and wind conditions are the primary reason for the spread of this disease.
The fungus can enter healthy or injured plant tissue, girdling the trunk and killing it. As the disease progresses the tree quickly loses any landscape appeal due to the grotesque shape it assumes.
Remove and destroy all infected wood by burning. Spray the tree with lime sulfur prior to bud break, and with Captain or Bourdeaux mixture after leaf-out.
Once started, this is a difficult, if not impossible, disease to control. If you live in the country where wild cherries surround your property, you should work on eliminating those plants as they serve as vectors for infection of our cultivated species.
Q: Is there a spray available locally to use after our flowering crab tree has blossomed, to prevent it from forming fruit? Its so pretty in the spring and so messy in the fall. (Jamestown, N.D.)
A: There are a couple of sprays available, but the timing is past for them. Sevin, a common insecticide, has been used at full blossom, and Florel, a fruit eliminator, has also been used for the same purpose. Both have limitations and limited successes. It appears that timing is extremely critical, as well as the cultivar of crabapple. Order either of these materials in March next year to be ready for the spring blooms to open, and see what kind of luck you can have.
Q: Please let me know the name and care of the cactus. It's about 5 feet tall and at the bottom it's starting to get brown and crusty. (Amherst, S.D.)
A: Your plant sample is an Epiphyllum sp., but which species, I cannot tell. In general, these cacti need direct sunlight, dry soil, no fertilizer in winter, and cool conditions during winter months. If the plant is starting to decline, I suggest taking cuttings like you sent me, to root and perpetuate the plant.
Q: I live in Crosby, N.D., and I have three Adeliene Hoodless rose bushes. I planted these roses five years ago. They used to be covered in flowers from early June until late August. The last two years, they have only about half the flowers and are done flowering in late July. They then send up 3- to 4- foot shoots which have no flowers on them. I have been using a Miracle-Gro fertilizer which is supposed to be formulated just for roses. I would appreciate any advice you could give me to return these roses to their former flowering vigor. (Crosby, N.D.)
A: The rose scion, or bud-wood, is slowly dying and the rootstock is sending up sucker growth from the root system. I suggest cutting the sucker growth back completely whenever it appears and continuing to fertilize as you have been in the past. Make sure the roses are not shaded from adjacent plant material which may have grown quite a bit over the past couple of years. Other than the possibility of insect or disease problems, I cannot think of any reasons why they should be declining.
Q: I can't seem to find any information on the plant called Lilac-Mexican Heather, Cuphea hyssopifolia. Can you help me on this?
A: Your plant is an evergreen in zone 10 (south Florida). It prefers moist, but well-drained soil, full sun, and is killed off if the temperature goes below 32 F. It also known as False Heather.
Q: Last year we lost one of our apple trees to rabbits. We have a seedling that came up from the roots, will this bear fruit? I believe this one was a Harelson. We also have a Red Baron apple tree that half the branches on one side died. It looks like it could fall over, it's so unbalanced. It also has this fungus-like growth. Does this need to be treated? It doesn't seem to affect the leaves or blossoming.
We also have a Habelred apple tree that has a black powder like residue on some of the branches. What is it and should it be treated?
What is the best proven chemical to use to kill dandelions, keeping in mind that we have young children and a dog? (Barnesville, Minn.)
A: The growth from the roots is very likely a rootstock sucker growth. The rootstock is different from the top growth and is likely to result in something unwanted.
The fungus is a saprophyte feeding on dead or decaying wood. The black powder is sooty mold. Pruning to open the canopy of the tree will help to control this superficial fungus growth.
I would encourage you to put up with the dandelions in your lawn if it is going to be used for romping and playing by the family. If they are just too much to put up with, then Confront applied according to label directions would be an example of an acceptable herbicide.
Q: I recently read one of your reader's requests for growing and marketing herbs for a profit. I would also like to have this information sent to me. Is there much demand for these types of crops to earn a substantial profit? How large an operation must one have to profit from herbs and spices? I hope your article addresses these and many more issues. (Jamestown, N.D.)
A: It looks like herb popularity is here to stay. Grow some for a year or two as a hobby; join associations, find the easiest, and possibly the most profitable manner to market them (dried). All I know is that the folks who are successful work very hard to be so!
Q: What are the waxy deposits at the base of leaves on an indoor fig tree? They appear periodically and I pick them off and occasionally spray the tree with a chemical, but I assume we are not treating it correctly because they reappear. If they are left long enough on the leaves there is almost a sap that comes off the leaves onto the carpet. What is it and what do we do about it? The plant has been in our home for about 20 years. (Moorhead, Minn.)
A: The waxy deposits are actually scale insects, and their feeding does cause "sap" to be deposited on leaf and other surfaces.
The best control is exactly what you are doing—wiping them off. Insecticides are not very effective as their waxy covering gives them protection.
How they got into your home is anyone's guess. Perhaps you received some plants or flowers as a holiday gift? It doesn't take much to get an insect infestation started and out of hand, so I encourage your vigilance!
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Source: Ron Smith (701) 231-8161
Editor: Tom Jirik (701) 231-9629