February 20, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We received a mailer advertising a particular tree that sounds too good to be true. According to the ad, the paulownia tomentosa grows to roof height in one year and grows to 40-50 feet high in subsequent years. It supposedly grows in almost any soil and is hardy to -30 F. What is the life expectancy of a tree that grows that rapidly? How about disease resistance or ability to tolerate strong winds? We have a 3-year-old house in Burleigh county on two acres of land. The wind blows incessantly and the sandy soil makes it difficult to grow trees. We and our neighbors have our lots outlined in lilacs and/or dogwood, but they are still only 3-4 feet high. I have two apple trees and two silver maples planted in our yard for shade and wind reduction. The trees are approximately 8-10 feet high. Would it be practical to plant a couple of pawlonias to get immediate shade and hope they die by the time our other trees mature? Tree placement is limited because of our septic system and I don't want to have these trees compete too closely with the maples near the house. There is plenty of room on the upwind side of the lot where the paulownias would actually shade the maples as well as the garden from the late afternoon sun. Is there another tree that you would recommend for a windbreak or fast shade? I understand that cottonwoods and poplars are outlawed by our local housing association. What about Chinese elm, or terragana ? (Bismarck, N.D.)

A: The "miracle princess tree" is making its way into the market once again! When something sounds too good to be true, it almost always is and the paulownia is no exception. It probably would not survive in the location you describe. It is marginally hardy in zone 5, where it can get protection, and officially hardy in zone 6 or 7. The wood is extremely brittle so it would probably get blown apart during the first summer. If it did survive the summer winds, then our negative temperatures would surely kill it. In short, you wouldn't be happy with it. A similar tree and almost as fast growing is the catalpa. It isn't a beauty, it gets large and has messy "bean pods" but it is hardy and tough enough for most North Dakota conditions. We have one (at least) on the NDSU campus in Fargo and it appears to have weathered the many storms that have hit us over the years without too much trouble. I'd suggest visiting the local nursery and checking out what they have that is tough and fast growing. They may or may not carry the catalpa since it is more of a reclamation type tree and not a beautiful ornamental. As a kid I used to love the tree for the big white blooms and the "super beans" they produced. I won't tell you what we used to do with the seeds.

Q: I have been growing a jade plant for about 10 years. I live in Ontario, so it is outside all summer and does wonderfully, except for some brown spots on the leaves. When I have to bring it in, it drops leaves and looks spindly even with a grow bulb on it. My problem is that instead of one or two strong main stalks it has developed 14 in a 36-inch round pot. The stalks are small in diameter and bend and curl over the edge of the pot. I love the look of a large strong jade with one or two thick stems. Did I prune it improperly while it was growing? (Ontario, Canada)

A: You might have a jade plant with a root rot problem. Check to be certain that isn't the case by knocking the plant out of the container and then use your eyes and nose to detect any rot developing. Whether or not that is the case, take some cuttings and root them for new plants. Keep them in strong indirect light for healthy development of the branching system. Jade plants should be repotted at least every three years, in an African violet type potting soil, watered very little during the winter months and summered outdoors if possible.

Q: A friend of mine received an advertisement for zoysia grass. Is it really the miracle grass they claim it is? (Fargo, N.D.)

A: Thanks for the question. It is an annual question that needs to be addressed early on. I just love our advertising media. Everything is either a "miracle" or "breakthrough," never something to just consider. Zoysia is a warm-season grass that is slow and difficult to establish, even in Texas. Once established, it is beautiful, at least, in the deep south not up north in our near-permafrost region. It turns brown (dormant) when the temperature is at or below 40 degrees and greens up only when the temperature stays dependably above 70 degrees. It spreads via stolons but does it very slowly even under good conditions and goes dormant with the first frost. It is commonly sold as plugs which is the only way to go as the seed is usually not readily available. It takes 2-3 years to get a complete cover in adapted areas of the country. If your friend lives in the "transition zone" of the U.S. which is the southern part of the northern region or the northern part of the southern regions of the country (Kansas, Missouri, etc.), I would say it is a go for zoysia to help battle the heavy infestations of crabgrass those regions have. I still wouldn't go as far as to call it a miracle grass. That noun should be saved for happenings that surpass all human or natural occurrences. Getting a grass to survive as far north as Boston doesn't quite cut it to be a miracle. Thanks for the question because it may stop future questions regarding zoysia from coming in!

Q: We have a Chinese evergreen in the hallway. The top leaves are green but every now and then one branch or bracket turns yellow. What causes this problem? (Valley City, N.D.)

A: Chinese evergreen, aglaonema commutatum, is a very durable and attractive houseplant.

The yellowing appears to be nothing more than normal senescence (aging).

Q: I’m looking for the address of a New York state tree and fruit tree nursery. I don't know the name of the mail-order business. The nursery specializes in zone 2 and 3 hardy stock. They carry many wild shrubs and native berry trees. They also list heritage apple and pear trees. (Thief River Falls, Minn.)

A: I know exactly the nursery you are talking about. It’s the St. Lawrence Nurseries in Potsdam, N.Y. All of their products are organically grown, hardened off and not pushed for size with high nitrogen fertilizers.

There are a number of ways you can reach Bill and Diana MacKentley.

1. Phone: 315-265-6739
2. Email: trees@sln.potsdam.ny.us 
3. www.sln.potsdam.ny.us 
4. Surface mail: 
   St. Lawrence Nurseries
   325 State Hwy. 345
   Potsdam, NY 13676

If you call and reach Bill, watch out, this man will talk your ears off about plants!

Q: I have a hibiscus that bloomed very well all summer and fall. The last two months its leaves started turning yellow and falling off. Does it need to be fertilized? What kind of fertilizer should I use? (Valley City, N.D.)

A: Your hibiscus is attempting to go into a rest period. Allow it to do so by backing off on the watering for the next two to three months. Water only enough to keep the soil from drying out completely and keep the plant in a cool room (55 F. best). In March cut the stems back to a desirable length, move it to a sunny location and increase the watering frequency. Once new growth appears, begin fertilizing every two weeks with a high analysis potassium fertilizer. Schultz, Miracle-Gro and other quality products are on the market for your selection.

Q: I enjoy your comments, but don't throw out all cyclamens. I have a survivor. I was given a gorgeous plum colored plant for Christmas, 2001. It bloomed until September. I continued my regular treatment which included, almost every day, rain water with a few drops of Miracle-Gro. It dropped very few yellow leaves and began sending up new ones which then turned to flower buds. By the next Christmas it was even lovelier with more than thirty flowers. It is in an east window with lace sheers. It has been a delight for me every day. (Aneta, N.D.)

A: Thank you for proving me wrong on this species. If everybody had your talent for growing cyclamen, I wouldn't give out such advice. Keep your thumb green!

Q: I have two large containers with the most beautiful green foliage from cuttings taken from a kalancho plant. I have had this plant for more than three years. As it stopped blooming, I noticed root-like growth on the stems so I began to root them. They thrived and multiplied. After having them out on the deck last summer, I brought them inside and to my surprise buds are appearing. What I should do to encourage the new buds and bring them to bloom? When the plant dries its blossoms, how far down should the trimmings go? Thank you for your help and we enjoy your Q&A in our local paper. (Lisbon, N.D.)

A: Spring is the normal flowering time for this succulent. Don't cut flower buds back but do prune them after they have flowered. Do not over fertilize or over water. Allow the potting soil to dry between waterings. After flowering, like many house plants, it needs to be given a rest period for about a month in a windowsill that gets no direct sunlight. Allow the soil to go completely dry. Then move it back to a sunny location and resume normal watering. Thank you for the compliment about the column. Folks like you make it interesting with your questions.

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