June 5, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I bought a jade plant about eight months ago. Some of the leaves are drying up and falling off. I did not water it much during the winter. How often should it be watered? Also, when I first brought it home, it was nice and full but now the branches are growing tall and leggy. Should I cut it down? If I do, at what point on the branch should I cut? (E-mail reference)

A: Your jade is probably responding to a low-light level situation. If you can’t get it to a location where it will receive bright, indirect light or direct sunlight, it will be leggy as you described. Jade plants respond well to intelligent pruning. Cut it back to a lateral branch or leaf axis - never leaving a stump. Jade also lends itself to easy propagation, so whatever you cut off, try and root it in a 50-50 sand and peat mixture to perpetuate the plant for family or friends.

Q: I’m trying to transplant some small oak trees that I started from acorns a few years ago. They are about 3-feet tall and have tap roots about that long. I've dug up a couple but have trouble getting all the tap roots out so I end up breaking off part of it. I usually have at least 2-feet of it intact. Will they still grow or do I need the complete root? (Tioga, N.D.)

A: You don’t always need the complete root but the more you can get, the better. It also depends on the time of year. If you can move them early in the spring, before they begin leafing out, their chance of survival will be better.

Q: My wife and I just bought a new lilac bush and planted it against a wall of our house. Is there any danger of the roots breaking through the basement wall over time as it gets bigger? Would you suggest moving it away from the wall? (E-mail reference)

A: Only if you have a leaky, weak foundation or it is so close as to interfere with the overhang from the roof.

Q: I have some thin and bare spots in my lawn. I have access to a plentiful supply of city furnished, well rotted and screened compost. Can I use the compost on the bare spots with some grass seed or do you think it would be too rich? Should I buy black dirt instead? (Jamestown, N.D.)

A: The city compost may have a pesticide residue that you don't want in your lawn. I would simply scratch up the surface, sprinkle some grass seed on the bad spots and mix in a quarter inch of soil on top.

Q: My spider plant is growing well but the ends of the leaves are turning brown. I use distilled water only. I did repot the plant recently and found roots but no dirt. Is that my problem or am I doing something else wrong? I do fertilize it every three months. (E-mail reference)

A: If it isn't in the water then it is the soil mix. Since you have repotted and continue with the regime you describe, the brown tips should become a thing of the past. The ones that are already brown will not green up but the newly emerged will (or should!).

Q: Four years ago I planted three Scotch pines that were about a foot tall. They are now approximately four feet tall. Last spring we experienced some major flooding in our yard. For about four weeks we had water three inches deep where the trees are located. When winter came they still were relatively green except for the tops, which were starting to turn brown. This spring all three trees had lost their needles. I remember reading once that some species of fir trees will shed their needles for a period of time. Are they dead? If they are just shedding needles, how long before they will green up again? (Buffalo, Minn.)

A: My answer is simple -- give them their last rites because they are history. Shedding of needles takes place on 3-year-old needles, not the entire tree. Pines simply do not like standing water. Sorry about the bad news - you are not the only one to write to me about the flooding in Buffalo, Minn.!

Q: What is the best way to control sucker shoots or tree seedlings coming up in your lawn? (Jamestown, N.D.)

A: Tree seedlings can be controlled by simply mowing on a regular basis. With sucker sprouts from roots, try obtaining a sprout inhibitor to spray on the area after you have cut it back.

Q: My mother has a beautiful cotoneaster bush next to her house that will need to be moved. I believe it is about 10-15 years old and has been kept trimmed to about 4 1/2 tall by 4 feet wide. She's very sure it won't survive a transplant, but I'd like to get your opinion just in case it's worth trying. How extensive are the roots? Do they spread out or go down deep? (Lisbon, N.D.)

A: She is right. The chance of surviving a move this far into the season is very slim to none. She is better off with a new plant. The roots spread and go deep after this many years of growth.

Q: I recently purchased a cala lilly but I don't know too much about it. It thrived after I fertilized it and it grew several white flowers before I had to re-plant it. Lately, although new flowers are still growing, the older flowers are turning green. It seems healthy but is there something wrong with it or are the green flowers normal? I know it goes through a dormant period but I’m not sure when that happens. (E-mail reference)

A: Everything sounds normal from your description. Following normal ecological cycles, the dormancy period occurs in summer. Allow it to dry down for a few months after this cycle of bloom.

Q: We have a variety of mushrooms (brown/white, different shapes) growing in many places in our yard. Do you know of anything that kills them or prevents them from coming back without hurting our grass? We've been told the previous owners of our home cut down a few trees and that's where some of the larger areas of mushrooms are. However, they are scattered in some other areas as well. To complicate matters, we recently seeded parts of our lawn and are watering often. Should we wait for the grass to take before trying to fight the mushrooms in those areas? (Groton, S.D.)

A: What you are seeing are the fruiting bodies of the decaying process from the tree stumps, roots, and other rotting organic matter in the soil. There is nothing that can be used to selectively take care of the mushrooms. Simply mow them or kick them off. When you quit watering so much or when the spring rains let up, the mushrooms will temporarily disappear. They will appear again when soil moisture levels increase. The alternative is to dig everything up and remove all the existing decaying material which is too much work for most people.

Q: What fertilizer should I use or what is the trigger to get cala lilies to bloom? I have 7-year-old plants that I have maintained and keep a good, strong set of bulbs each year. They have not bloomed since the first year. They are in 14-inch clay pots and the foliage always looks great. (E-mail reference)

A: The trigger for most plants to bloom is to give them enough light. In this case, some direct sunlight. Also, allow them to go into a dormancy period every summer by withholding water. Fertilizing with any good houseplant fertilizer every two weeks during active growth will usually get them to flower. Once they have entered dormancy, keep them in some direct sunlight, even outside for the summer, as long as there are no rainy periods. Bring them inside for the winter, assuming you live where winters go below 40 degrees, then start watering again.

Q: I have large perennial beds (approximately 600 or so plants) with a few annuals mixed in around my home. I’ve been noticing some of the leaves are turning yellow. On the majority of them the leaves are yellowing and the veins are somewhat green. I am guessing they are lacking iron. I would like to send you soil samples of about three different areas in my beds. How much do you require and what is the charge? Also, what can I do to amend the soil? I have used a liquid iron formula that you attach to a garden hose. I will be adding a granular fertilizer and Miracle-Gro. (Not all at the same time, of course!) When I add new plants, I mix compost in with the soil. I will admit that I have been lax with composting in the fall like I should. I will compost now but should I do it again in the fall? Should I do something else? I mulch with wood chips. Should I clear away from each plant and compost or can I put the compost over the chips? How much should I use? Also, can you please tell me the difference between compost and humus? Is one better than the other? (Glyndon, Minn.)

A: The amount needed for the soil test lab is about a pint or a sandwich bag full. Get the pH, N,P, K, soluble salts and organic matter checked for each sample. The cost is approximately $20. Send it to the NDSU Soil Testing Lab, Fargo, ND 58105. You want to amend the soil based on the soil test results. The mixing of organic matter with the soil is always a good procedure. Compost is vegetable matter that has gone through a decaying and breakdown cycle that involves human interaction to move it along. Humus is another term for "woods earth" where the decomposition has taken place over the years (sometimes called "cold composting") and is composed of the plant material that has fallen to the forest floor. I really don't know that one is better than the other.

Q: A lady has flies gathering on her porch where there is shade and are "leaving their mark" up the side of the house. What kind of residual spray can be used to control house flies outside? Do those sprays have any affect on steel siding such as discoloring? What else would you suggest for controlling flies? It is not a sanitation issue as it is a very clean yard but it seems the flies just like the shade! (Amidon, N.D.)

A: Malathion is the typical fly control. I don’t know if it leaves a permanent stain so I would suggest trying it on an inconspicuous area first.

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