Different years and seasons can produce different colors
The Washington Post's gardening columnist Adrian Higgins answered questions recently in an online chat. Here is an edited excerpt.
Q. I have two Japanese maples. One is planted in the ground. The other is in a bonsai pot. Last year, the leaves on both trees turned yellow in the fall. This year, both trees' leaves turned red. What's with that?
A. Leaf color is a fluid thing, and based on all sorts of environmental factors - sunlight, rainfall, temperatures - so it's possible that when one fall is markedly different from another, different pigments will come to the fore once the chlorophyll departs.
Q. My childhood home had three quince trees, which my mother would use to make the best jams throughout the year. Could you please direct me in how to go about planting a tree - where to buy and how to maintain?
A. For fruiting quince, you should go with Cydonia, not Chaenomeles.
Q. Can you tell me whether there are any backyard uses for cut Christmas trees after the holidays?
A. Apparently, if you have a farm pond and throw it in, the little fish love a dead Christmas tree as a place of cover. It's too woody for the compost pile. You could remove the branches and use them as a winter mulch on such things as artichokes and dahlias (if you're brave enough to leave them in the ground).
Q. Can you recommend a shrub that would do well in shade, have scented flowers and serve as a spreading screen for unsightly parts of the neighbors' property?
A. Osmanthus comes to mind. Very fragrant and evergreen. Camellias would also do the trick, though they're not really fragrant. Another might be clethra, which is not evergreen.
Q. My petunias are still flowering in pots, so I haven't yet pulled them out. I didn't even bother to do chrysanthemums this year. However, I'm a little worried that I should be anticipating a freeze and empty my clay pots of soil. Is there a general rule about when to remove the soil from a pot that is not frost-proof - or should I just hope the autumn will linger a little longer?
A. The issue isn't the soil, it's whether the container is freeze-proof. Most clay pots are not. You should toss those annuals and put the old soil on the compost pile or spread it on beds. (It's a false economy to reuse it.) Then your pots are best cleaned when dry with a stiff brush and stored where they won't get wet. Before using them next spring, a scrubbing with a bleach solution will take care of any lingering plant disease organisms.
Q. Is it too late to plant spring bulbs? I've got a bag of daffodils that have been kept in a cool place and they look OK, but I'm not sure whether they will grow.
A. No, it's not too late. In a month it will be. However, it is getting late, and poorly stored ones should be checked for rot before planting. If they're soft, chuck 'em out. Get them in this weekend!
Q. Is any particular kind of bulb best to plant this late?
A. The best to plant are late-season tulips, daffodils, alliums and camassias. Early stuff such as snowdrops might be a problem.