August 15, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: Can you tell me if the leaves of Engleman ivy, peony or hosta are poisonous? (Cando, N.D.)

A: The Engleman and peony are suspect; the hosta has no references to any poisonings.

Q: I would like to know if it is safe to water trees, flowers and lawn with water that contains 500 parts per million (ppm). of sodium in the water. What is the tolerable level in the water, and if this water is continued will it build up in the soil? (Tioga, N.D.)

A: This level -- 500 ppm of sodium -- is well within the acceptable levels for growing turfgrass. When it reaches as high as 2,000 ppm, injury may occur, depending on the soil type, frequency if irrigation, and the relative proportions of calcium and magnesium in the soil. Just make sure that your irrigations are complete -- that is, total wetting of the root zone and a little beyond to prevent accumulation of salts from building up.

Q: Would it be safe to move my yucca plant now? (Fargo, N.D.)

A: Go ahead and move it with as much care as you can provide. They are pretty tough customers and have a high survival rate.

Q: I have read your column and know your recommendation that black knot be trimmed from chokecherry trees. On many farms in North Dakota such as mine, the shelterbelts are made up of hundreds of chokecherries, far too many to cut black knot from, using ladders, etc. Thus, these shrubs are dying, a real loss to these prairie shelterbelts. Is anyone developing a spray for this disease? Considering the magnitude in the apple orchards of the USA, I would think the USDA should be doing something. (E-mail reference, N.D.)

A: There is a spray program for these trees, but it often comes too late to save them. Annual spraying of all fruit trees while they are dormant in the early spring with lime-sulfur is about as old as I am, but is a practice that has not been a habit with most gardeners/horticultural farmers. It acts as an excellent general sanitizer, allowing the trees to leaf out surrounded by relatively clean tissue. A product called Cavalier can also be used in conjunction with lime sulfur. That product can be sprayed at pink bud stage, full bloom and three weeks after full bloom. These actions, in addition to selective pruning where possible, will go a long way in saving many of the chokecherries if caught in time.

Q: I am planning to purchase a home with a large silver maple in the back yard. Close to half of the major branches have no leaves. The others branches have normal looking (from 30 feet below) leaves. I know this is not a lot of information, but does it sound like the tree is dying?

Also, I have noticed several silver maples in town with a yellow tinge to their leaves. I assume this is unusual for the middle of summer. Is there some pest or disease that is affecting silver maples in the Fargo area? (Fargo, N.D.)

A: The silver maples in the Fargo area typically suffer from iron chlorosis due to the high alkalinity of our soil. If you are considering the purchase of the home based on the tree, then I think you will be disappointed when the tree completely expires in a year or so. Silver maples can be beautiful trees if cultivars for our region are selected. Cultivars such as 'Northline' and 'Silver Cloud' are from the Canadian prairies and will certainly develop and outperform any seedling non-cultivar that might be planted in our region. Keep those names in mind if you purchase the house and end up having to take the tree out.

Q: I have a jade plant that I purchased last December. It has grown quite a bit since then and has already been transplanted once. The plant is healthy and seems happy in its current location. However, due to all of its growth, it is looking "leggy" and unkempt. Is it possible to prune a jade? I have seen older jade plants that have beautiful branches and appear to have been pruned or shaped in some way. Can you please tell me how to proceed with this plant? (E-mail reference)

A: Floppy jade plants are usually an indication that the plants are not getting enough direct light.

Yes, they can be pruned. and some people are successful in creating interesting looking plants by taking PVC coated copper wire and carefully twisting it around the branches to get them to grow the way they want. This would require careful monitoring on your part to make sure that the wire did not girdle the branches you are trying to shape. Since they root easily, I suggest taking the cuttings that you remove and rooting them into new plants. Younger ones are easier to work with.

Q: Approximately 70 years ago, my father grew a variety of red tomato named Red River, which I recall was hybridized by your facility. For many years seeds of this variety were cultivated by our family. It was our favorite. However, because of moves which precluded any vegetable gardening for a few years, we lost track of seeds for Red River tomatoes. (E-mail reference)

A: I have never heard of that variety of tomato, but perhaps someone will have some seed that they would be willing to share with you. If I get any kind of positive response, I'll connect the two of you.

Q: I made a mistake and sprayed our garden with Tempo 20 WP. The active ingredient is cyfluthrin. It can be used in food handling areas but not on food crops. Can I use any of the produce from our garden or are there certain types that I can use? (E-mail reference)

A: If it isn't on the label, you should not consume it. Since this is a Bayer product, you might try getting on their web site to see if they can provide you with a label or further information. I am sorry, I don't have a label in my references.

Q: I understand that a crepe myrtle blooms on new wood. If I deadhead my crepe myrtle will it bloom again in one season? (E-mail reference)

A: Be careful how much you prune! "Deadheading" is not proper pruning of anything that is a shrub or tree specimen. Cut back nothing larger than the diameter of your thumb. It will bloom on subsequent growth. Try to get the pruning done ASAP to avoid winter damage.

Q: We have a grapevine that we planted about three years ago. It has really outdone itself growing this year. A few days ago, my husband noticed some of the leaves have little bumps on them. When he turned it over it looks like when spiders make an egg nest. Now they (the under side spots) are turning brown, but the leaves are still green and otherwise healthy looking. The grapes are starting to turn their purple color. What is it? We don't want to spray unless we have to. Would just removing the affected leaves help? (Dilworth, Minn.)

A: Yes, I would just remove the affected leaves, since I don't know what it could be, and I don't like to advise spraying with anything unless it is a strong necessity.

Q: I bought a peace lily at a grocery store. It was in a very small pot so I transplanted it. This was about a month or so ago. Now the leaves are turning brown at the ends, some just the tips but some more. The flowers aren't white anymore and have turned green. I had it in a south window but moved it away from the window and it isn't getting any direct sunlight. What is the plant missing? What am I doing wrong? We live in a trailer house, does that affect plants differently? (Bismarck, N.D.)

A: The Peace Lily or Spathiphyllum, is among easier plants to grow, so you have picked a good one. It does well in low light situations, making it ideal for homes and offices. It requires a lot of water, but good drainage. I suspect that you either have it in a container that is not free-draining or in soil that holds the water too long. They will sunburn, so your moving it from a south window was a good move. Unless your trailer is a new one with a lot of chemical smells from the solvents and glues used in construction (my wife and I used to live in one, and for about the first week, we kept the windows open as much as possible to let everything air out!), it should have no problem there.

Q: I read with interest your questions on jade plants, but unfortunately did not find the ailment that plagues mine. The plant is old and has thick stems that go from brown to green. They are not in the center of the pot, however, and instead the plant is growing out over the edges. In addition, when I pinch the upper leaves it does not sprout new branches from the bottom up. Rather, branches sprout from the upper parts of the stem, and then grow long and droop. Needless to say it does not look like the healthy thick jades I've seen elsewhere. Am I not pruning it right? What would happen if I cut off a thick portion of the stem? How do I get it bushy in the center of the pot? (E-mail reference)

A: The plant sounds like it isn't getting enough light. Jade plants need strong direct light, even sunlight, in order to be bushy and self-supporting. Try moving it to a sunnier location to see if that improves the lot of the plant, and take some cuttings to root, to build a new plant that you find appealing.

Q: I have a plant called Datura meteloides 'Cornucopaea’. Could you give me any information on care, when to prune, and so forth? No information other then that it is a sun loving plant, came with the plant. At present I have it in a pot, outside, on the south side, and it's blooming. However, before the blossoms open up completely they burn off. I have tried moving it to partial sun and the buds began to fall off. Also, how do they multiply? (Stickney, S.D.)

A: The datura you are referring to is a cultivar that will not open its flowers much beyond the tube stage, if at all. It thrives in sun and heat and can only be grown as an annual in the north.

All parts of the plant are poisonous so be careful that no children or pets handle the leaves, flower, or fruits. The fruit that is formed is how they multiply.

Q: Are the berries of the Canada red cherry edible? I have loads of the beautiful red berries on my three trees. (Vergas, Minn.)

A: If you mean edible as in not being poisonous, yes. Eating them out of hand like Bing cherries, no. They make excellent jelly and jam and, I am told, good wine.

Q: After plants in the daisy family have finished blooming, should you cut back the spent blossoms, or are they like tulips and need the nutrients to go back into the plant? (Bismarck, N.D.)

A: Deadhead the flowers back to where they emerge from the foliage. This keeps the plants from expending energy into making seed.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu