February 14, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We have been feeding birds (sparrows) all winter and our neighbor has complained saying that there are so many birds roosting in his pine tree at times that it is killing the tree. The birds feed twice a day, usually morning and right before dark and then disappear. Is there any truth to this? (Fargo, N.D.)

A: If sparrows have the power to kill pine trees, then the trees were not very healthy to begin with. No one could have more birds roosting in their trees (two Ponderosa pines and an Amur maple) than I do, waiting for their morning and afternoon feed to be delivered. In other words, I doubt the veracity of that statement.

Q: I have a Canada red cherry tree that gets growths on the branches. I have noticed a couple of others around town that also have them. I would like to know what is causing these growths and what I should do, and if they are threatening the health of my tree. (Ray, N.D.)

A: The fungal growth you are seeing on your cherry tree is black knot. Basically, pruning out and destroying the infected branches and spraying the tree with a product called Cavalier will control the disease in early stages, but if the infection is too bad, complete tree removal is the only answer. Because of the widespread nature of this disease, I no longer recommend planting the species in our region.

Q: I have a hoya displaying contradictory symptoms. Most of its vines are drying out at the ends while at the same time thick yellow leaves are dropping (mostly at the base of the plant). I got the plant from a lady who didn't want it. It was vined around a planter she wanted to keep so we had to cut it free. It had been in this planter for five years. I kept all the cuttings and have plants from every one of them. The mother plant had a dozen or so flower stems. All of those vines have died off. Last year I replanted it. There has been no change. The top of the soil gets dry while the bottom stays damp. I watch it closely so I don't overwater. (E-mail reference)

A: The hoya or wax plant needs warm, direct sunny locations in well-drained soil to do well. It sounds like one of those factors is missing, or a root rot has begun on the plant. I suggest you knock it out of the container, check the roots, and possibly repot or discard.

Q: I potted a spider plant about a year ago from a plantlet. It has developed brown streaks in the middle of the leaves and the leaves have become rippled like a potato chip. The plant seems to have stopped growing. What is the cause of this? I looked at the base of the pot and I can barely see the roots poking out. Is it time to repot? The plant gets two to three hours of direct sunlight in the winter. What are some tips to ease the transition to a larger pot if need be? (E-mail reference)

A: The likely problem is the air being too dry (low relative humidity) combined with the direct sunlight hitting the foliage. Throw into the mix the possibility that the salts may be elevated at this time of year, and you then have your reasons for the anomalies in your leaves. Repotting would never hurt. This is among the toughest and most easily grown houseplants. It should respond very favorably to the slightest TLC, and often outlives the owner.

Q: I planted two Japanese tree lilacs near my patio. The first year they were full of blooms, the second year nothing, although the foliage was very beautiful and appeared very healthy. How can I get the blooms back? When is the best time to prune in my Illinois garden and still encourage growth? Also, how tall can I expect them to grow? I was hoping they would give my patio a little shade. (E-mail reference)

A: You probably pruned the plants too late in the season. If any pruning is needed, do so right after they have finished blooming. I assure you they will provide shade for your patio, as they will get to 20 feet or taller.

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