Q: It is finally getting cold outside, and I have begun moving my houseplants indoors. I have a couple of orchids that were out for the summer, and they occasionally fell off the shelf they were on and are missing some of the bark potting mix. I have heard that plants shouldn't be repotted in the fall. What should I do?
A: You know the old saying that rules are made to be broken? This is one of those situations. It is usually better to repot plants in the spring so they can grow new roots and shoots together. In the fall, the plant is going dormant, and the extra potting soil may not get any new roots and may, at the same time, stay too wet, possibly causing the roots to rot.
But anytime a plant is missing soil, it is appropriate to fix the situation. You could just add some new orchid mix to the pot, or you could take the plants out of the pot, trim off dead roots and replace the whole mix in the pot.
Q: I have an amaryllis that was outside for the summer, and I want it to bloom this winter. I took the plant in last fall and kept it growing all winter, but it didn't bloom. I took it back out this summer, and now I want to bring it in again, but why didn't it bloom, and what can I do to make it bloom?
A: Amaryllis plants will reliably bloom if given a dormant period of a couple of months. The plants you buy all boxed up in the store were harvested months ago and stored in dry, dark conditions. When you buy one and start watering it, you wake it up, and it blooms.
It may feel a bit cruel, but remove your amaryllis plant from the pot, and shake or wash off the soil from the roots. Take a pair of scissors and cut off all the roots and leaves. Cut the leaves off about an inch above the bulb and the roots all the way off.
Leave it out to dry for a day or two, and then place the bulb in a dry, dark spot for a couple of months. About a month before you want it to bloom, repot it into a pot about an inch wider than the bulb using new planting soil. Next summer, you can plant it back outdoors, and it should live for many years.
If it sends out a side shoot or two, you can grow new bulbs. When you move the bulb out for the summer, break off the small side bulbs and plant them in their own pots.
Q: I bought a small bonsai plant this summer. According to the tag, it is a Japanese garden juniper. It says that the plant should be left outdoors for the winter. How can such a small plant survive the winter? In my area, the temperature will reach below zero several times. This doesn't make too much sense to me.
A: I agree that it doesn't seem to make sense, but it does. Many plants are as easy to grow as bonsai, but the biggest problem is giving the plant the proper winter care. Tropical plants that never experience cold are the easiest to grow because they can be kept indoors all year in cold climates and outdoors all year in warm climates. Plants from cold regions, like your juniper, need to experience a cold dormancy period to continue growing properly.
Very low temperatures will not bother the juniper if it is growing in a garden, but in a small pot, special care must be taken to get it to survive. The roots are the most sensitive to extreme cold because they are normally growing underground, where they don't usually get too cold.
You can bury the pot, leaving the trunk and branches aboveground. They can then be covered in straw, or a frame can support an unheated covering of plastic over the plant. The greenhouse method can heat up too much on sunny days, and the soil must be checked to make sure it doesn't dry out.
Check with your local bonsai society for local members' recommendations. It may even have someone who can keep your plants with his over the winter. Some greenhouses keep plants for their customers.
Jeff Rugg's weekly column, "A Greener View," can be found at creators.com.