Nutgrass, Gardenias & Plum Trees

'Mystery' gardenia

‘Mystery’ gardenia

Q: Some friends of mine had a beautiful lawn here in the San Fernando Valley, but they have nutgrass growing in it. I had never heard of it, but everyone on their street has it.
Can you recommend something they can do to make it look better? The gardener put some stuff on it a while back and it went away, but now it’s returned. Do you have any solutions?
— Marla Orlow,
Granada Hills
A: What you refer to as nutgrass is actually yellow nutsedge (Cyperus esculentus), which may be the worst weed in Los Angeles. It is easily identifiable by its shiny leaf blades and hard, nutlike underground tubers. Complete eradication may not be possible. But there are some anti-nutsedge chemical products available at nurseries.
Make sure you follow label instructions precisely. For more thorough control, you may wish to consult with a horticultural pest control company, which you can find either in the Yellow Pages or on the Internet. Local companies that come to mind are National Pest Control (818) 984-3670, Greenleaf Organic Pest Management (818) 752-9989 and Mitchell Pest Control (626) 987-1106.
Nutsedge is native to Egypt, where its edible tubers are harvested and roasted. It is related to several water-loving plants that are suitable for growing in ponds. The most widely seen is the umbrella plant (Cyperus alternifolius), which may pop up almost anywhere and will spread with weedy determination unless it is relentlessly chopped back or excavated.
Umbrella plant grows up to 5 feet tall with many parasol-shaped leaves. It is valued, in some quarters, for its durability as a container plant, whether on the patio or indoors.
Umbrella plant joins a select group of indestructible species that started out as indoor plants, but somehow found their way into the shade garden, including mother-in-law tongue (Sansevieria), spider plant (Chlorophytum comosum) and cast iron plant (Aspidistra elatior).
The most famous nutsedge relative is papyrus (Cyperus papyrus), encountered both as an aquatic and partial-shade garden specimen, growing to 6 or 7 feet tall. Misled, perhaps, by its somewhat wispy and delicate-appearing foliage, some people make the mistake of giving papyrus too much shade, which will inhibit its growth or kill it outright. Make sure that papyrus has good ambient light, but take note that `King Tut,’ a 2-to-3-foot-tall dwarf papyrus, is a bit more shade tolerant.
Q: My potted gardenia plant seems healthy but every bud it gets never opens. First I had it in an afternoon sun area, then I moved it to a morning sun area and the buds still form and then wilt. I also have a plant in the ground and I get the same problem. Any suggestions?
— Eileen Dunn, Northridge
A: Gardenias are the most challenging plants to grow in Los Angeles. I would suggest moving yours around until they find a spot to their liking. I have found that gardenias thrive when they are in the proper location, which is wherever they receive the most humidity your garden has to offer. The healthiest gardenias get either most of the morning or some of the afternoon sun. Their roots should be consistently moist, but not wet, and well-drained soil is essential to their health. A constant fertilizer feed, whether from slow-release pellets or a complete liquid fertilizer with micronutrients, is helpful.
Two years ago, I planted a Gardenia jasminoides `Mystery’ that had been grafted onto Gardenia thunbergia rootstock, and I’ve been pleased with its lush foliage and abundant flowers. Gardenia thunbergia is a sturdy species grown as a tall hedge or screen in partial sun. It has tougher roots than Gardenia jasminoides and is not as sensitive to changes in soil moisure. You should be able to special order this strong grafted gardenia at most nurseries.
Q: Our 15-year-old plum tree usually has enough fruit to feed the whole neighborhood, but this year we are lucky if there are a couple of dozen plums on it. We thought maybe it was because we did not prune it, but the same thing has happened to a friend and she thought it was because they pruned theirs too much.
– Eileen Witham, Simi Valley
A: The productivity of plum trees drops off dramatically at 15 to 20 years of age, so this may be the reason for your small crop. Also, we received late rain this year, which could have either knocked off or led to contamination of your plum blossoms. Lastly, plums sometimes exhibit alternate bearing tendencies, which means that a heavy crop one year may be followed by a lighter crop the next. Established plum trees should not be heavily pruned, except for rapidly growing water sprouts, since they produce fruit on spurs, which grow less than an inch a year, on older wood.
TIP OF THE WEEK: If you have trouble keeping your container plants hydrated in scorching weather, you may want to supersize them. Large plants in large containers — whose volume is at least 15 gallons — should not require more than two weekly waterings, even during a heat wave. Smaller containerized plants, especially in pots that are 5 gallons or smaller, will probably need to be watered daily.

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