November 15, 2001

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: Leaves on my lilac are curling up as if they are not getting enough moisture . We had quite a dry spell so I watered it regularly. It is getting plenty of moisture now but the leaves are still curling . It is 5 years old and has bloomed beautifully last year . Should I cut it back to the ground so that it can start over ? Do you think maybe it is dying? (Sioux Falls, S.D.)

A: From the information you have given me, I would try to save it by cutting it back. If it survives, it will not bloom next year, but will the following year, under normal conditions.

There are a lot of things that could be affecting the lilac; borers, canker and root rot to name a few. They are generally tough plants and come through just about any adversity.

Q: I need to cut down a mountain ash tree that has fire blight. I would like to know if I can chop this wood up and use it for mulch, or will this procedure continue to spread the bacterial infection to other plants or trees in my yard or my neighbor's yard. (Bismarck, N.D.)

A: It will be a vector for the disease, should there be any members of the rose family nearby (apples, pears, raspberries, etc.). If you compost it first, getting it to a nice high temperature of 140 degrees plus, that would cut down on the incidence of disease and the locking up of nitrogen.

Q: Can you give me direction on growing camellia indoors as a potted houseplant? I am wondering about temperature, light, watering, feeding and how to get them to bloom. (E-mail reference)

A: Glad to help you! Here are the recommendations: bright filtered light all year, keep them in as cool a room as possible during the fall and winter, where the temperature can range from 45 to 60 degrees. Dry winter heat will keep camellias from blooming or cause bud abortion. Stand the pot in a tray of pebbles filled with water to keep the humidity high around the plant. Keep the plant well watered throughout the active growing period, then at the end of the flowering period, water only enough to keep the mixture from drying out, a period of about six weeks. Fertilize every two weeks during the active period of growth.

Q: My spider plants have these little tiny grayish-green spots developing on many of the leaves. I pruned off a lot of the leaves that had a lot of spots on them, and I also took off all of the little baby plants so that more nutrition would go to the plant itself. But the spots aren't going away. Actually they're getting worse. I'm worried that maybe the plants are not getting enough sun. The sun only shines in my window for an hour or two a day, and it's pretty dim the rest of the time. (E-mail reference, Detroit Lakes, Minn.)

A: Your problem could be related to the low light intensity it receives most of the time. I suggest moving the plant to another window where more light can reach it or, give it supplemental lighting with a plant light. You could also be overwatering it, something easily done when the plant is starting to decline in low light situations. The condition that then develops is known as edema, which could be what is affecting your plant. You shouldn't have removed the spiderettes. They are an excellent propagation source and not an energy drain on the parent plant.

Q: We built our home 17 years ago and planted many bushes with ornamental rock surrounding them. Last winter we lost a lot of bushes (mostly evergreen, but also some deciduous) and have been removing them this summer. I am not sure I want to replace them as it has been a lot of work trimming them and getting the fall leaves blown out of them. However, I am at a loss what I should do. Just having the rocks looks plain. Do you have any books or publications you could recommend with ideas or maybe plants that require less care or landscaping ideas using a minimum of plants or other things? (Milnor, N.D.)

A: Yes, perennials; and I strongly suggest the book "Growing Perennials in Cold Climates" by Mike Heger and John Whitman. ISBN # 0-8092-2943-9, cost $50, obtainable at well-known bookstores. It’s loaded with pictures and ideas and well worth the investment.

Q: As I was cutting down my old raspberry canes I noticed a swelling in the stems of some of the new canes. Upon further investigation I found a white larvae in the node that was about one-half inch long. Would you know what species this might be, what its life cycle is, and what actions might control this pest?

A: Most likely a raspberry cane maggot. The only control is to cut out the infested portion of the stem a few inches below the swelling and destroy.

Q: I have one flower bed with iris that has quackgrass in it. Can I use Roundup? Another flower bed on the north side has tulips and lilies in it plus lots of quack. I have tried Preen back there, but by the time the snow is all gone the quack has started to germinate. (Cooperstown, N.D.)

A: Roundup is a non-selective herbicide, killing anything it touches that is green and growing above the soil. It can be used safely over tulip bulbs since the foliage is not now present. You can "wick" the Roundup over the foliage of the quackgrass, keeping it carefully off the foliage of any desirable plants. Fall is the best time to do this.

Q: I have three tree stumps that I would like to remove. I am not able to dig holes and put in stump killer and burn it out. I heard that you could get rid of the stumps by using zucchini and putting them on the stump somehow. Have you heard of this or was I misled? (Wayzata, Minn.)

A: I have never heard of that one before! There is stump remover available from local garden centers, where you drill holes into the stump pour in the material, and it disintegrates over time.

You can also rent a stump grinder, or hire someone with one to do it. They can turn the biggest stump into sawdust in a matter of minutes.

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