March 20, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I've become interested in sweetgrass and I'm wondering if it is reasonable to expect it to grow in my back yard. I see that plugs are readily available by mail order but I have no idea about its hardiness or containment although it must have some stamina to proliferate in this part of the world. Your thoughts? (Fargo, N.D.)

A: Sweetgrass (Hierochloe odorata) will likely not do well in our area as a perennial. I have seen it in Ohio and Indiana gardens. I tried it once on my own here in North Dakota but it died over winter. If the price is right for the plugs, I encourage you to get some and work up the soil well with peat moss before planting. Keep them in full sun and moist but not soggy. Even as annuals they are interesting and attractive. If we go back to our old-fashioned winters where we get a good snow cover before the really cold temperatures move in, there is a good chance that you could get the plants to survive for a few years. I would bet they wouldn't survive an open winter like the one we are currently in with the sub-zero temperatures. Give them a try because the scent from the foliage is worth it even for one summer!

Q: I have planted some paperwhite bulbs that are doing well. I would like to know how to take care of the bulbs after the flowers are done blooming. How long do the bulbs have to rest before you can plant them again? (Battle View N.D.)

A: Paperwhites are the most tender of the narcissus bulbs. Once they have stopped flowering, allow the foliage to remain. Keep it in natural bright light until it deteriorates. Once that’s done, a rest for a few weeks would probably be in order. Then plant outside in pots or inside again for reblooming. I have no direct experience in reblooming paperwhites and none of my references have a time line on the required rest period either so I am giving you my best guess. They are definitely not hardy enough for outdoor planting in North Dakota.

Q: I have three pothos (Devil's ivy) in our office, each in a different room. They are doing very well but one of them has grown to huge proportions. The stem is three quarter inches across and two inches around. The leaves are about 7 1/2 x 10 1/2 inches. I searched the Internet and it says the leaves should be two to four inches which is true of the others in the office. It started growing like this after we moved here from another office. The only difference between the two offices is the lighting. The only difference between the location of this plant from the others is that this one is by a north window while the others have no window at all. I am baffled as to why it is growing the way it is. Could it be strictly the lighting? (Moorhead, Minn.)

A: I doubt it. It is more likely you have a chimera developing. Contact me again this spring when the weather is a little nicer and I will try to make a run over to your office to see if that is the case and if so, take a cutting from it.

Q: I have a bad problem with tomato blossom rot. I have been told it’s caused by a calcium deficiency. I have tried a foliage spray with mixed results. Is there some other way to address this problem? Also, my annual flower bed dirt has become so gumbo like that the plants will no longer root. I live in Crosby and the water comes from the city’s lime softening plant. I think this is part of the problem. I am going to replace the dirt and start over but I have to use the same type of dirt for replacement. What can I mix in with the native dirt to prevent this problem from recurring? (Crosby, Minn.)

A: Blossom end rot is a cultivar/environment interaction. Generally the cause is from overzealous cultivation that damages the roots and results in a reduced nutrient uptake. It could also be from a wide fluctuation of watering or rainfall. Finally, some cultivars in some climates are prone to this malady, at least with the initial fruit set, thought to be tied with cold soil or cold water in the root zone. But, since you told me that the water source is already softened, and most likely with sodium, the problem is that particular cation is in such high concentration that it is destroying the structure of the soil and negatively affecting the growth of your plants. You need to get another water source or treat the water with a RO unit to remove the salt. It will simply cause the problem again later on even with all the soil being replaced. Canadian sphagnum peat moss is an excellent soil conditioner, and I would suggest incorporating generous amounts into the soil to improve the tilth.

Q: I have a couple of questions about plant propagation. Do you have to let the cut surface of geraniums dry before rooting a cutting? If you cut the tops off of a pepperomia will it send out new shoots from the bottom? Do you have to let the cuts dry before rooting? I have a goldfish plant that I got as a few sticks in a cup. It is now a very full plant with some of the shoots more than 3 feet long. Four of the shoots, probably the original ones, blossomed this fall. If I cut off the long shoots, can I cut them into sections to re-root or will just the tips grow? (E-mail reference)

A: You don’t have to let the geraniums dry before rooting, although it won't hurt if they do dry but not too long. Pepperomia will send out new shoots only if there is a latent bud there and depending on how much of a stub you leave behind. No need to let the cuts dry before rooting. Your goldfish plant should root if the stem has finished flowering. To help the process, add bottom heat and use a rooting powder.

Q: I am trying to find an evergreen that likes moist soil. I’m planting a wind break by a pond but am not sure of what type of tree to plant. Can you help? (White Bear Lake, Minn.)

A: Arborvitae, white spruce, black hills spruce (variety of the white) and balsam fir. That's about it!

Q: I can be of help to one of your readers who had a question about her aunt's jade plant. The little white strands she described are indeed roots. You will see them occur along the trunk and/or branches of the jade plant, especially when air conditions are humid, or anywhere that the plant's branches touch the soil. I've also seen this occur in other succulents such as a Christmas cactus. It's very easy to take cuttings at these points and start new plants. Sometimes if the roots begin forming, and conditions become too dry, they will dry up and fall off. I don't think treating them with rubbing alcohol would be such a good idea! (E-mail reference)

A: Thank you for your interpretation of the problem. It’s something I didn’t think of! Obviously rubbing alcohol wouldn't be called for in this situation. I just had my head too much into thinking it was a problem. I publish questions and answers to get feedback from readers like you. No one can know everything or have all the right answers. Again, thanks!

Q: I was just reading the question about the jade plant. Mine has air roots also and they definitely are roots growing out of the plant stem. I never thought anything of it since my sheffeliera seems to also have an excessive amount of air roots. Maybe they are both suffocating from not getting dusted! (Aberdeen S.D.)

A: They definitely are roots. If it was your objective to propagate these plants, now would be a good time. They are not suffocating so don't worry, it is just a step in the process of plant growth with these tropical species.

Q: We are having trouble with our green spruce pine trees. They are approximately 30 feet tall and about 40 years old. They have lost their deep green color, as well as being pale, droopy and losing needles. We did keep them well watered and fertilized with slow release fertilizer spikes following the label instructions. We did go through a drought last year so we watered them well again before freeze-up. Do you have any recommendations? We really want to save these trees for many reasons. (Napoleon, N.D.)

A: It could be a number of problems, either singly or in multiples. Spider mites, needle cast disease or high soil salts from a rising water table I suggest sending a sample to our plant diagnosis clinic to the attention of: Cheryl Biller, plant diagnostician, NDSU Department of Plant Sciences and Plant Pathology, Box 5012, Fargo, N.D. 58105-5012. Be sure to send a representative sample showing healthy and diseased or stressed plant tissue and give her as much background information as possible. There will be nominal charges depending on the tests carried out. I am definitely not an advocate of fertilizer spikes, so I would recommend not pursuing that path any longer.

Q: I live on a farm near in the central part of South Dakota. We would like to plant a tree in the front of our home which would have three or four trunks and white bark. We are looking at something on the order of an aspen or birch and hopefully a tree that won’t grow higher than 30 feet at maturity. Your recommendation for specific species/varieties would be appreciated. (Highmore, S.D.)

A: You are aiming directly for a white clump birch, but I would encourage you to consider a river birch, clump form, instead. The cinnamon-colored bark is very attractive and the tree is far more adaptable to our Dakota prairie environment and will live a lot longer. If you can, try and get the cultivar known as heritage. It is a tree to equal or beat out the best. In fact, if there was a champion of Champions, this tree would be it. It tolerates 40 below cold and can stand heat found in three zones south of you! Even if you have to go out of state to get it, do so.

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: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu