Q When I visited Charleston, S.C., I fell in love with a beautiful plant that had a cluster of red flowers at the end of stems with shiny, thin, dark-green leaves. I was told this is an oleander plant. But isn't oleander poisonous to people and animals? How, then, could it be used so liberally in public landscapes?
Do nurseries in the Washington area stock the oleander plant, or is this area too harsh a temperature zone for it to thrive?
A Oleander is not very hardy in our area. I have kept plants alive outdoors through early March, but it seems that any dip below freezing after the first nice days of spring kills them. Oleander is widely planted in the Southeast and the Southwest despite its reputation for being extremely poisonous. Your concern allows me to discuss the issue of poisonous plants.
There are lots of horticultural references to poisonous plants, and most houseplants and many ornamentals appear on some of these lists. The problem is, they often lump extremely poisonous plants together with plants that are mildly toxic. Readers who are alarmed by the information then rid their homes and gardens of all the plants on the list without gauging the true risks, which in many cases are slight.
However toxic a plant may be, its danger is relative to the amount of vegetation ingested and the sensitivity of the individual. Many poisonous plants don't taste good, and it's highly unlikely that a child or pet would be able to ingest enough to threaten its life.
Misinformation abounds this time of year about firs, pines and poinsettias being poisonous. I love to eat and will try almost anything, but I have never had the urge to eat an entire poinsettia and three fir branches.
My gardenia summered on the screened porch, but now that it is time to keep it indoors I have discovered that it has mealybugs. I tried a spray solution of water, dish soap and Tabasco, which didn't work. Would the water-soap solution work better with rubbing alcohol? Short of tossing a beautiful plant, any suggestions?
Mealybugs are very difficult to eradicate, but there is an ace up the gardener's sleeve. The gardenia can survive some freezing weather, but most mealybug species cannot. The snag is that the gardenia must be properly acclimated before it receives the cold treatment.
If you've already taken the plant indoors, it will have lost cold-induced dormancy and may even be trying to grow or bloom. If this is the case, you will have to treat the mealybugs indoors and leave the cold treatment to next year.
But if it is still on the screened porch, simply leave it there. It should have stopped any growth by now and is well equipped to take temperatures as low as 25 degrees with no problems. It should be taken indoors once temperatures are forecast to drop below that.
If the gardenia is in a clay pot, the freezing conditions might crack it. Put the gardenia in a same-size plastic pot for the winter.
If your gardenia is inside now, you should apply rubbing alcohol on the mealybugs with cotton swabs. Save the Tabasco for your scrambled eggs.
I have grown a miniature rose in an 18-inch clay pot on my patio. The bush is now about 24 inches tall and until recently was still blooming happily. How can I keep this bush alive over the winter? We move our clay pots inside our garage for the winter.
Miniature roses are perfectly hardy in our area. Take your rose out of its pot and plant it in a sheltered location in the garden. You may want to mound leaves or clean straw around it for protection from the worst of the cold winter winds. Let the pot dry thoroughly before you store it in the garage, to avoid freeze damage. When spring arrives, you can move the rose back into the pot, give it some fertilizer and prune it a bit to stimulate new growth.
Scott Aker is a horticulturist at the U.S. National Arboretum.
Have a question about gardening? Write Digging In, Home Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071; fax 202-334-5059 or e-mail home@washpost.com.
