NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

February 18, 1999

Hortiscope

Ron Smith, Extension Horticulturist
North Dakota State University

Q: A couple of weeks ago you answered a question about propagation of juniper from seed. How are these propagated by cuttings? What other trees can be propagated this way? (Dickinson, N.D., e-mail)

A: Junipers root easily from current season's growth and last year's growth in a pure sand media. Simply make cuttings about 9 inches to 12 inches long and strip off any foliage from the lower 3 inches. Insert in clean sand and keep moist. They should form roots in about four to six weeks or less.

Others that can be propagated that way are mulberry, magnolia, St. John's wort, viburnum, crabapples, dogwood, holly, some birch and juneberry (with patience and practice!). Pines do not root from cuttings. Their seeds have no dormancy and can be germinated upon collection. In some cases, better luck is obtained by using a rooting hormone such as IBA. The cut ends are simply dipped into a talc containing this material then stuck in the medium.

Q: Can you tell me what is wrong with my trees? The needles are turning rust colored, mostly closer to the trunk, and moving outward. Is there something we can spray them with ourselves? (Martin, S.D.)

A: There is no way I can tell whether or not your spruce had needlecast without examining a sample.

The trees can be sprayed with Bravo (chlorothalonil) in June and July with any sprayers that have not had herbicides used in them earlier. Doing this for a couple of years will usually arrest the spread of the disease.

Q: Enclosed is a leaf from my African violet. The whole plant is covered with these fine particles. Can you tell me what it is and how I can get rid of it? (Marion, N.D.)

A: At first I thought they may be fertilizer salt crystals, but upon close examination, it turned out they weren't. So, now I am at a loss as to what they are!

They appear benign and nonpathogenic, so I wouldn't worry about it unless the plant declines.

Q: We have a ditch in front of our house that is too steep to mow. I was wondering if there are some flowers that I could plant in there to enhance the look of this area? My husband is a farmer, so he is concerned also if we can kill them if we want to. (Munich, N.D., e-mail)

A: There are plenty of wildflower mixes that you can select from that would be very attractive to even your husband. The planting should be mowed or burned once a year while dormant, either in the early spring or late fall.

Q: I have a Dieffenbachia picta, Rudolph Roehrs. It has lost the leaves on the bottom but the top is beautiful and continues to develop leaves. It is getting kind of top heavy. Can I repot the plant in a deeper heavy container so that all the bottom without leaves would be under the soil? Would the covered stem develop roots or rot? I am also wondering when do I bring out my geraniums to repot them and do I completely cut them back and watch new leaves and stems emerge from the crown? (Fargo, N.D., e-mail)

A: Good question. I don't know what the results would be. It could root if you wounded the stem in a couple of places at about 1 inch below the soil line, and assuming that you would keep the well-drained media moist, but not wet, you could likely get roots developing at those points.

A method I have used that works 98 percent of the time is to cut the plant back to about a 6- to 9-inch stem, then take the remainder of the stem that was cut off, and cut it into about 3-inch pieces. Take those pieces and lay them horizontally in a sand/peat mix, and half cover these pieces with the media. Keep moist, and in about six weeks leaves will emerge from the ends that were nearest the bottom. Or, you can take the top that you have cut off and simply try rooting it in a pure sand medium. The cut-off stump will usually develop new leaves shortly as well.

It may be a good idea to wear rubber gloves when you are handling this plant, as it can cause a rash on some people.

Your geraniums may be just about right for repotting now. You would first want to immerse them in tepid water for a few hours to rehydrate them. Then if there are stems long enough, take cuttings and attempt to root them in sand. Otherwise, pot up the mother plants and set them in as sunny a location as possible, keeping them watered and fertilized as they start showing new growth. Set them out, of course, when all threat of frost is over.

Q: I have a metal barn that I would like to cover with vines. Do you have any suggestions? (Hitterdahl, Minn.)

A: The fastest-growing vine that I know of is the Virginia creeper or woodbine (Parthenocissus quinquefolia). It will grow just about anywhere and cover anything that stands still for two weeks! Thanks for writing!

Q: When I lived in California we had a flowering plant in our backyard that was called Moonlight Jasmine. The aroma in the evening was wonderful, and I have asked people around here but no one knows what I am talking about. I would like to grow it here and I am trying to find a place to purchase it. (Lengby, Minn.)

A: I am not surprised that no one in this part of the country knows what you are talking about! It simply is not a hardy plant in our zones. It grows as far north as zone 7, which is a long way from Lengby, Minn.! That zone travels across southern Oklahoma, the panhandle of Texas, and into the southern parts of New Mexico, Arizona and California.

If you want to grow something with a nice fragrance try Abend Duft or the night-scented stack. It's not much to look at, but sure smells great. It is an annual.

Q: I ordered some strawberry plants and this other plant came up with them when I planted them. It got real tall with little yellow flowers. Can you tell me what they are? (Eureka, S.D.)

A: Your mystery plant was a weed known as velvetleafsomething you don't want to encourage! So keep any future volunteers rogued out before they flower and set seed.

Q: Enclosed are two leaves from my hoya plant. Can you tell me what is wrong with them? Also, can you tell me what are the best keeper onions? (Braddock, N.D.)

A: The only thing I can figure is that a "do not" has been committed somewhere:

The only other possibility is a temperature fluctuation. Being native to tropical India, they do not take well to temperature exposure below 55 F to 60 F.

The best keeper onions are the long-day type, that are high in sulfur compounds and pungent in flavor. Try to get Autumn Spice, Spartan, Sweet Sandwich, Sleeper, Spartan Gem, and Fiesta. Try to get sets and plant early.

Q: Is rain water good for watering plants that are having trouble with salt accumulation? (Valley City, N.D.)

A: If you are using rain water, it is essentially salt free so is not the source for the salt accumulation with your plants. Most likely it is coming from the fertilizer you are using, especially if the plants are growing in a container without free drainage.

The problem could be your potting soil. If it is native soil, it could have a high-enough salt content that sodium could be in excess. Again, especially so if there is no free drainage from the containers.

At this point, I would suggest repotting with a different media and in a fresh, free-draining container. Other than this, it sounds as if you are doing everything correctly!

Q: Enclosed are a few more of the "dotted" flies that have been bothering us. Can you identify these and tell us how to get rid of them? (Litchville, N.D.)

A: The insect samples arrived in good form this time, and were identified by entomologist Denise Olson as picture-wing flies. They are only pests, the larval stage feeds on decaying organic matter. They are likely coming in through window openings, cracks in walls, or as you come and go into and out of the house, if the entryway is near any kind of refuse pile.

Knock down household sprays are suggested.

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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.

Source: Ron Smith (701) 231-8161 ronsmith@ndsuext.nodak.edu

Editor: Dean Hulse (701) 231-6136