Q: My grandmother's Christmas cactus is in my living room. Right now it doesn't look good. It has long stems and baby leaves. Do I need to repot it? What type of soil do I use? I fear it will not survive and would be crushed if it dies. Please help me since this cactus is very sentimental to me! (E-mail reference)

A: It sounds like repotting is in order. Do you have it in a bright enough location? They need bright, indirect light. I would suggest propagating it from cuttings, if you can, to help assure its survival.

Q: I read an answer about an Oregon Spring tomato (nearly seedless). I was wondering if you could tell me where I might be able to purchase seeds or plants? (E-mail reference)

A: I think you would be better off, at this stage of the season, waiting until next spring. You can order seeds from Tomato Growers Supply Company, Box 2237, Ft. Myers FL 33902. Their phone number is: 1-(888)-478-7333.

Q: Because of the drought this summer, much of my lawn grass has died and has been replaced with weeds. I am planning on replanting this fall but am not certain which variety of grass will work best for me. We live along the White River in western South Dakota so our soil is somewhat clay-like. We recently drilled a new well, and that water is very high in sodium, (1300mg/l), sulfate (3200mg/l) and conductivity (6500mh/cm). It is also very hard, testing at 70. The only flowers that grew for me this summer were zinnias and moss roses. Do you have any suggestions for grass varieties or annuals that might do well? ( Kadoka, S.D.)

A: You might try some Ruby creeping red fescue. If that doesn't make it, then try Roadway crested wheatgrass. If that fails, then try Fults alkali grass. If that fails, you are out of luck. Marigolds or wave petunias might make it.

Q: I read in one of your oak questions that one should not drive on the roots of a tree or it will die in three to five years. You also stated that you can put down plywood and drive on it and be ok. Does this theory hold true for most trees? I have seen a couple of oak trees so close to the road they have put traffic warning diamonds on them to keep people from hitting them as they pass. They are just a few inches from the road with asphalt covering some of the roots. Does the asphalt keep them from being hurt? One of these trees is by a hospital and has been there for the 23 years I’ve lived in the area. Does driving on the roots (compacting the soil) matter to all trees or just some varieties. (E-mail reference)

A: Life is full of confounding anomalies that defy logic. Yes, driving over tree roots will compact the soil, driving the air out. It will eventually kill the trees, usually over a period of three to five years. Placing plywood sheeting over the area helps spread out the compaction, cutting down on the severity of it significantly. That said, I have been building a slide collection over the years that shows trees that should have been dead long ago, as there was no visible source of water, nutrients, or air. Yes, some tree species are more resistant to soil compaction, but don't tell them that or they might die on you!

Q: I have an area on the west side of my house (right next to the house) where I removed a rose bush about four years ago. Since then, I have not been able to get anything to grow there. I have tried grass, plants, even laid sod and that died. The area is not excessively sunny or shady and is well drained. Can soil, where rose bushes have been, go "sour"? (Kindred N.D.)

A: In horticulture, as in many things, anything is possible including this but I have never heard of it!

Q: I have a question about pears trees. I have a parker pear and a summer crisp pear. They both produce blossoms but not very many and do not produce any pears. What can I do to help them produce? The trees are healthy and grow well. The trees are 12 years old and have produced only once but I don't remember which one it was. (Enderlin, N.D.)

A: Could it be that you are too good to them? Try root pruning by driving a sharp spade into the soil at several spots around the outside of the tree canopy. That often stimulates them into their reproductive cycle.

Q: I just read your response to a reader about not using fertilizer spikes for arborvitae bushes. You mentioned that they are a bad investment. You said she should use Miracle-Gro. Is that your feeling for evergreens or arborvitae in general or her situation only? I have used spikes in the past on small evergreens but am wondering if I should stop doing so. (Fargo, N.D.)

A: Here is my take on fertilizer spikes. Years ago I conducted a study on spikes and found them to be more damaging to the immediate roots then a benefit. Also, they were losers when calculating the value received compared to the price paid. I tell many people, if what you have been doing is working well for you, then stay with it no matter what I believe or say.

Q: We have a flowering crab in our front yard. It produces too many apples and makes a complete mess out of the sidewalk and therefore the entrance to the house. I need to do something. It is a beautiful tree but the apples are a mess. Your article says you can spray it with Sevin. Where do I find it? At a local flower shop? Help! (E-mail reference)

A: Your chance of success with Sevin is about as good as hitting a home run playing in the major leagues. It SOMETIMES works but not always and not with all crabapple cultivars.

I have the same problem. My solution is to remove the tree. I don't like the mess on the lawn nor the yellow jackets that are attracted to the rotting apples.

Q: When is the best time to transplant clematis? (Ontario, Canada)

A: In the early spring when it’s dormant or this fall after leaf drop.

Q: What is the best time to prune back a Ninebark? I planted one last year and it has flourished beyond my expectations. Can I contain it's growth to less than the 8-by-8- foot natural growth without jeopardizing the overall appearance? I am in a Zone 5 (possibly 4) area. (Ontario, Canada)

A: Yes, by selectively cutting out the thickest stems, back to the ground, each year. Don't remove more than a third of all the branches.