Submitted by: agcomm, Thu Oct 2 11:38:29 1997 Hortiscope Ron Smith, Extension Horticulturist North Dakota State University Q. Enclosed please find some leaves from our chestnut tree. This tree is 6 feet tall. It grows about a foot per year and the leaves are nice and green, but as summer comes these leaves start turning brown like the samples. Any suggestions would be greatly appreciated so we can get this tree to look better. Thanks for your help. We enjoy reading your column in the Sun Country and have learned a lot from it. (Lehr, N.D.) A. Your tree is an Ohio buckeye, similar to a chestnut. Unfortunately, the seedlings of Ohio buckeyes are subject to leaf scorch for which there is no spray for curing. This commonly happens in areas of the landscape where competition for soil moisture is high. The best bet is to try and water during the growing season to keep the tree well hydrated and make it believe it is along the moist banks of the Ohio river. Q. Thanks for all of your help in the past. I really do appreciate it. Would you please tell me what kind of weeds these are? Also would you please tell me what is wrong with this mock orange? I read to spray with fixed coppers for blight. What are fixed coppers? How do I tell if I have a male or female bitter sweet vine? I read also that you have to have both. I bought some Tempo for grasshoppers but it does not list grasshoppers on it to kill. I was told not to use it in the garden. It does not say this either. How do shamrock plants go dormant? Do they lose their leaves or just not flower? (Winner, S.D.) A. The weeds are barnyard grass and oxalis or wood sorrel. The third one is prostrate kurtweed. The mock orange has septoria leaf spot. Protect next spring after leaf-out with a multipurpose fungicide such as Bordeaux mixture, which contains the copper you are asking about. Bitter sweet are like holly bushes--no two sexes, no fruit--but will grow anyway. I guess you have to depend on the integrity of the nursery to include both sexes in the container. Tempo can be used in the landscape and on lawns for good grasshopper control. Use either Malathion or Sevin in your garden. Shamrock is a name given to many species of clover-like plants, generally Oxalis species. The ones I know set seed and die, with the seed sprouting later. Q. We enjoy reading your column and get useful information from it. I never thought you could kill rhubarb, but we lost one of our three long-producing plants two years ago. This spring we fertilized with barnyard fertilizer, but one hill was slow to come and was spindly and weak. Leaves turn red and dry up. I called Master Gardeners and county agents and they could give me no help. I was wondering if you could tell us why this is happening and what to do about it. I know of rhubarb hills well over 70 years old and still producing. Thank you. Frazee, Minn.) A. Rhubarb plays host to a number of diseases which can be fatal. In your case, the sample you sent had indications of Anthracnose and a virus, likely one known as turnip virus. Anthracnose is spread in wet springs. The virus is transmitted via insect activity. Thank you for the kind comments about the column. I have to take exception to your comment of 70-year production from one rhubarb plant. If this is so, it must have been moved several times. Generally, six to 10 years in one location is max. Q. I have a question concerning a perennial flower or perhaps it is a common weed. This plant grew on the farm where I lived in west central Wisconsin about 70 miles east of the Twin Cities in the 1940s. I had not seen it for many years, but when I was recently in that area at Menomonie, Wisc., I found it again and would like to have it identified. It was growing in an area with cattails. We used to call it "kisses over the garden gate." I am not going to attempt to plant it and have been very careful not to scatter the seeds in case it is classified as a noxious weed. If you cannot make an identification could you please send me the address of the Horticulture Department at the University of Wisconsin at Madison. I would appreciate any information that you can give me. Thank you. (Barnesville, Minn.) A. You are "smart" to not scatter the seeds of smartweed--in this case Pennsylvania smartweed--Polygonum pensylvanicum. While your care in handling the plant is appreciated, it has long since spread over the midwest. Commonly found in ditches and other low, swampy areas. I have never heard it called "kisses over the garden gate"! Thanks for writing and the good sample. Q. Enclosed in the box are two specimens. What is the hard black lump off my Canadian red chokeberry tree? Any prevention? The sick impatiens are here and there in a group. Plants around them look healthy. Is there any information on this and is there a prevention? You have been a great help in the past and I thank you. (Oakes, N.D.) A. Your chokecherry has a fungus disease known as black knot. Normally, not a severe problem on cultivated stone fruits like your cherry. This disease has been showing up more frequently these past couple of years. The best control methods are to prune out the visible knots, at least 3 to 4 inches below the swelling. Also check around your property and adjacent lots to see if there are other cherries with the same disease. Spray with lime sulfur next spring before leaf-out, and apply a protective fungicide like Bordeaux mixture once the leaves have opened. Your impatiens sample looked amazingly healthy with the exception of a few leaf spots, which might be a touch of botuytis due to the wet conditions the plants are normally kept in. Just try to avoid splashing water when irrigating. Thank you for the nice compliment. Glad I have been helpful. Q. Thank you for all the useful information you give us all in the Farm Forum. Your column is the first I turn to when the "Green Sheet" arrives! I am enclosing a sample from a white pine (Pinus strobus) that was planted in June of 1994. Right now it is about 5 feet tall. For the last two years in the spring the tree needles are completely brown like it has died. Then all summer I feed it Mir-Acid and get it to green again. Does it have a disease I could spray for? Also I am enclosing a sample from a pee gee hydrangea that was planted July 6,1997. There were two bushes planted at the same time. This year one bush had many blooms on it, but the other is not blooming at all. I have examined the leaves, but cannot see signs of insects and the plant looks very green and healthy. Could you please advise me as to what I could do to get this bush blooming again. Thank you for your time. (Grenville, S.D.) A. Your white pine has nothing wrong with it. I am afraid that will be the nature of the plant since it is growing where it shouldn't. Continue doing what you have been and you should be able to enjoy the tree for many years. Concerning your hydrangea--the only guess I can make is that the non-flowering one may have been pruned too late in the growing season, or it is in too much shade. From the looks of your sample, growth and leaf size appear normal, so it could be a pruning problem. Thank you for being a fan of Hortiscope. People like you make it interesting. Q. I am sending a good leaf and a bad one hoping you can tell me about this plant and the name of it. I have had it for four years and its very big and pretty, but the leaves turn brown around the edges. I don't know if it's too much water or not enough. I give it Miracle-Gro once every two weeks. What am I doing wrong? Please let me know and give me the name of the plant. I love to read your articles and hope you can help me. Thank you. (Linton, N.D.) A. Your plant is the Chinese evergreen, Aglaoneura species, an easy plant to grow that likes ample water in a well-drained container. Your problem may be that the container is no longer draining the water freely from the root system, and causing the browning, or it may be that you have the plant located too near an air conditioner vent. They like it warm, with no cold drafts. Q. I have a problem with a double yellow rose bush. This is an older variety and quite hardy. It blooms faithfully every year, but then the flowers dry up and the entire bush turns brown. So far, it has recovered and leafs out again in a few weeks, and at the present time is green. I am wondering what I can do to keep from losing it. Thank you in advance. I really enjoy your column. (Isabel, S.D.) A. Having once been a rose fanatic myself, I now abstain from growing any. That statement doesn't answer your question, but it does give a clue to some frustrations in growing roses. I frankly don't know what would cause your rose bush to react the way it does. I do know that in my younger years when I could keep them looking prosperous, I followed a strict spray, fertilizer, and pruning regime. Even then, I was not guaranteed every year would be a success. When Rachel Carson's book, "Silent Spring," came out, I gave up all the fussing and let them die out. This was back in New York state. Well, after all this ranting, I advise the following with your rose: 1.Prune the rose plant heavily in the spring while still dormant. Be sure to get all diseased or cankered canes removed. Pick up all remaining leaves. Do this while the plant is still dormant. 2.Spray the plant before leaf-out with lime sulfur. This sanitizes the entire above-ground portion of the plant. Apply about cup of 5-10-5 around the base of the plant. 3.As new growth emerges, apply Orthene to control the whole host of insects that ravage roses and, likewise, apply a protective fungicide such as Rose and Ornamental Fungicide, multipurpose fungicide Daconil 2787, or Ferbam--the list is almost endless. 4.When watering, avoid overdoing it, and avoid splashing on the foliage. 5.Fertilize again after July 4. Good luck! I hope all of this helps. ### NDSU Agriculture Communication Source: Ron Smith (701) 231-8161 Editor: Naomi Dahlberg (701) 231-6263