QUESTION: Why do the green leaves on my poinsettias fall off as soon as I get them home, so only the red remain? I admit I've always bought bargain plants at the market. Could this have something to do with it?
--B.S., Los Angeles
ANSWER: Many years ago, bargain poinsettias were often older varieties, sometimes called "those lovely strippers" by growers because they shed their green leaves so quickly. However, almost all the modern varieties, even the inexpensive ones, should hold on to their leaves.
Surprisingly, the most common cause of leaf loss is being left in their shipping sleeve for too long, according to Jack Williams. He's with the Paul Ecke Ranch, a huge poinsettia grower in Encinitas.
He encourages retailers to immediately take them out, or unpack them, and even suggests that we consumers not buy a plant that is still in its shipping sleeve. That sleeve might be paper or clear plastic, but the poinsettia shouldn't still be in it.
According to Williams, varieties with light green leaves tend to drop them more quickly than those with dark green leaves. The darker green variety photosynthesize better and so are less affected by changes in light and other factors that put a poinsettia under stress.
Better-grown poinsettias are less likely to shed leaves because they are stronger plants, and it is more likely that bargain plants have been poorly grown. Try to check the roots by tipping the plant out of its container. If there are few roots or if they are damaged, completely dry, or overly wet and sodden, that could cause the plant to lose leaves.
Finally, don't bring poinsettias home to a hot, stuffy house or set them in front of a lighted fireplace. Poinsettias prefer cool temperatures, in the upper 60s, though they will get used to temperatures in the low 70s.
For the same reason, don't leave them outside overnight. It's too cool. Either extreme in temperature could cause them to shed leaves.
Lawn Should Thrive Despite Earlier Fungus
Q: For the last 18 years, I've had a lovely dichondra lawn, but it died out this summer. I think it was a fungus, the same one that blighted my tomatoes. Now I want to plant a Marathon lawn in its place. Can I get rid of the fungus first, so the new lawn doesn't die as well?
--M.Y., Long Beach
A: Dichondra has many pests and problems in California, but I doubt whether any of them are related to whatever blighted your tomatoes. Dichondra is susceptible to flea beetles, cutworms and a number of diseases including leaf spot, so it may, indeed, have been a fungus that did in the dichondra.
"But there is no magic pill that gets rid of fungus," said Martin Gramckow of Southland Sod Farms. Fungus spores are like bacteria, always there--waiting for the right conditions--and nothing really gets rid of them.
But whatever killed the dichondra will most likely not bother the tall fescue lawn. The real problem will be that dichondra seeds prolifically, and "while you can't keep it alive when you want it, you can't get rid of it when you don't," Gramckow said. It makes a marvelous weed.
Before putting in a new lawn, he suggests taking steps to sprout the dichondra seeds and then kill them with Roundup. You may need to water and spray several times before planting anew. Even after the new lawn is established, Gramckow suggests using some brand of a weed and feed fertilizer that will prevent dichondra seeds from germinating in your grass lawn.
You'll also want to thoroughly prepare the soil before planting lawn seed or sod. A poor soil may have hastened the dichondra's demise. Southland has a free video on how to do this properly. You can get a copy by calling (800) 4-MARATHON, or see it on the Web site at http://www.sod.com.
Not Polka-Dots but Freckles on Roses
Q: Why does my normally white 'John F. Kennedy' rose sometimes get pink polka-dots?
--M.M., Pico Rivera
A: It's similar to people getting freckles. According to rosarian Joe Brown with Weeks Wholesale Roses, at certain times of the year, and in certain weather, light-colored roses will develop reddish spots. It happens not only to white rose blossoms, but to light pinks and lavenders as well.
Spots may be caused by dew or moisture sitting on the petals when the sun is intense, as is often the case in the fall. The drops cause the pigments, even those normally not visible, to intensify in that spot--like a freckle--to protect the tissue from the sunlight. You could call it a kind of rose sunburn.
The dots seem most likely to appear when there are sudden fluctuations in the weather, such as cool nights followed by brilliant Santa Ana days.
You can avoid the problem, says Brown, by picking the roses early in the day before the sun hits them, when the buds are about one-third open. The spots are most noticeable on fully opened rose blossoms that are several days old.