I am pleasantly surprised that, based upon e-mails I receive, you still have an interest in the garden so late into winter. It must be because we are getting used to a 10-month growing season in this region. So, let's answer some of your questions.
Q: I am having a lot of difficulty finding a cold frame. Most garden supply sites and stores no longer stock them.--L.E. Lent
A: A cold frame is a bottomless box placed on the soil or over a pit, in which plants may be started, grown or stored. It is covered by a window that keeps plants warm and protected. Several models are sold by Charley's Greenhouses & Indoor Growing Supplies. Call 1-800-322-4707 for a catalogue, or look online at www.charleysgreenhouse.com. Peaceful Valley Farm Supply also sells one. Call 1-888-784-1722.
Instead of buying a commercial cold frame, you can construct one using lumber and an old glass or clear plastic pane that's still in its frame. Use four pieces of four-inch-square lumber (pressure-treated wood lasts longer) to make the frame and set it into a rectangular area of soil that has been excavated to a depth of about four inches. The window then rests on the lumber. The excavated area can be filled with compost or potting soil.
Cold frames provide winter protection for starting cuttings and a head start on growing all spring flowers and vegetables. Because it gets so hot under glass, providing some shade protection is a good idea to keep the seedlings from getting scorched. You can cover the frame with a cloth, paint the glass or site the frame in partial shade.
Q: I have a very large female holly from which I am trying to start cuttings. Please give me your advice.--Carol Miller
A: Generally evergreen hollies can be rooted from June to September. The part that you cut for rooting is the first flush of new growth that has started to harden off--still green, but not fleshy. Cut off six-inch stems; remove the lower leaves; dip them into a rooting hormone such as Rootone, and put into wet perlite. Keep the medium warm and wet. The sprigs will root in six to eight weeks. Pull the cuttings up to check on their progress. Once rooted, they should be planted in a cold frame or other protected outdoor location for their first winter. Then plant into the landscape with lots of compost the following spring.
Q: I intend to plant leyland cypresses along my property line. I have a wealth of information on their care, but realize that their initial health is a key factor for success. Can you recommend an inexpensive quality supplier that would deliver to McLean?--Robert Twining
A: Your dedication to researching the cultural requirements of leyland cypresses is admirable and will probably be the factor that ensures success. They are usually not grown by the garden centers where you get them, so any quality plant supplier will have healthy stock purchased from a commercial grower.
Choose a garden center that is close to you and will stand by its plants with a warranty. Plants should be full with healthy green foliage. The trunk should be firmly attached to the roots, not flopping back and forth. Find out what the warranty is before purchasing plants. Most companies offer delivery.
Q: I need help identifying and eradicating an insect that is killing my Otto Luyken. We lose about one a year. As we replace it, the next one in line shows yellow leaves and dies. The first bush we removed had a sluglike bug under the bark at the base of the plant and the bark had separated from the trunk. Any ideas?--Barbara Belechere
A: The sloughing bark is a sign that the wood is dead; it's not causing the problem. The most common causes for the type of dieback you describe are root rot diseases or funguses caused by wet feet or poorly drained locations. If you notice when you remove the old plant that conditions are "squishy" or the soil is gray, then poor drainage is definitely the problem. Fix the drainage by digging in lots of compost and making sure the planting hole you dig will drain.
Q: Please identify the beautiful trees with red berries at the Vienna Metro stop.--Jean Busby
A: Two flowering, deciduous trees that grace many Metro stations are hawthorns and crabapples. Both have striking winter interest because of red fruits or berries.
Q: Should we or should we not rake all dead leaves out of our flower beds? Most of the folks in our neighborhood raked their beds clear.--Ted Jewell
A: Most people garden too cleanly, as your neighbors have done. You can let leaves lay in your beds where they won't mat down over greenery and kill it. While you should pull accumulations off lawns, groundcovers and winter blooming plants, such as hellebores, letting leaves lie elsewhere will act as an insulator and root protector for your beds and plants. The leaves will need to be raked before new growth begins in spring.
I usually err in favor of less cleanup, use a rotary mower to chop up the leaves in spring and spread a little ornamental mulch, such as aged, double-shredded hardwood bark, to cover the leaves and dress up the beds.
Q: Before fixing my sewer line in December, I dug up some tulip, daffodil and hyacinth bulbs, and lavender and columbine plants. When can I replant them?--Emilie Hoppes
A: Plant as soon as possible, even though it is rather late into winter. The bulbs will dry or decay and won't be of any value if they are kept out of the ground until spring.
Plant the lavender and columbine now in a protected location and mulch heavily. These perennials can be moved again in early spring before they leaf out if they aren't exactly where you want them.
The bulbs can also be stored temporarily. Plant them in containers and keep them cool (40 degrees Farenheit) in your garage or basement where they won't freeze through winter. Move the containers outdoors March 1 and allow them to grow and season (when leaves become yellow or brown) after flowering in spring. Then they can be easily dug after seasoning and planted again next fall.
Lerner is president of Environmental Design in Capitol View Park, Md. His e-mail address is email@example.com