Finding Cannas
Q: I see cannas of many colors in gardens all over town, but I can’t find them at nurseries. Can you help?
--L.F., Los Angeles
A: Cannas have gone in and out of fashion several times with Los Angeles gardeners. They are, however, perennial favorites in the East, and seed catalogues offer the tubers in spring. One good source is Park Seed Co. (Cokesbury Road, Greenwood, S.C. 29647-0001), which carries 10 different full-size cannas three or four feet tall and five of the Pfitzer dwarf cannas--less than three feet. Park also carries the old-fashioned, seven-foot ‘Red King Humbert,’ with bronze-red foliage, and another old favorite, ‘Cleopatra,’ with red and yellow petals covered with red freckles. Other cannas come in shades of red, pink, orange, salmon and yellow. The tubers are planted in spring; each will grow two or three stems, one of which flowers. Cannas need full sun, thrive in the heat and require lots of water in the summer; they flower in summer and early fall. In colder climates, their stems die back, but in Southern California they should be cut back to the ground after the plants have finished flowering, or in the late fall.
Q: Last year I tried making my own soil mix for succulents and cactus, with disappointing results. It dries out quickly, stays very loose and is somewhat water-repellent. Can you suggest a good formula?--
J.S., Arcadia
A: Cactus collectors Seymour Linden and Henry Varney make up the following mix for their several thousand succulents, many of which are rare and quite finicky: four parts fine pumice, three parts LGM planter mix, one part decomposed granite or washed builders’ sand. Both swear by the pumice, which is available at Orange County Farm Supply (1826 W. Chapman Ave., Orange, (714) 633-8682). LGM, a brand name fairly common throughout Southern California, makes for a potting mix that is “dry, even when it is soaking wet.” Linden and Varney water fairly often with this mix; they suggest that one with less pumice and more sand or granite requires less watering.
Q: We have a strip of land where we park our recreational vehicle, but it is difficult to keep clear of weeds. Is there a way that we can sterilize the area?
--W.G., Los Angeles
A: Weed growth can be eliminated by using herbicides registered for such use: Diuron, Atrazine, Bromacil or Simazine. Because most of these herbicides have relatively long residual lives in the soil, be sure never to use them anywhere you might add landscaping later. Atrazine has the shortest residual life; Bromacil, the longest. Try to avoid one of the biggest potential problems encountered in using herbicides: They can sometimes migrate downward to the root zones of shrubs and trees that you want to keep.
Q: When is the best time of year to plant citrus trees? I’m thinking about a dwarf navel orange and a dwarf grapefruit.
--T.N., La Habra
A: Although citrus trees can be planted almost any time of year in mild-winter areas such as yours, early March planting is recommended for interior valleys and other areas that have hot summers. A wider choice of dwarf trees is available at nurseries at that time. Be sure to plant them in a location that gets sun most of the day; adequate sun has a lot to do with how sweet the fruit is. Although watering frequency should vary according to changes in the weather, a young tree should be given a soaking every seven to 10 days during the first year and every two weeks for the next two years. It is not a good idea to add fertilizer to the planting hole or mix it with the filling-in soil. Fertilizer should be placed in the irrigation basin about once each month before watering.
