October, with its cooler days and the occasional sprinkle (our Southern California “rainy season” actually begins in November), is the ideal time to plant most perennials, with the exception of tropicals, which should be planted in late spring or early summer, and bare-root plants, which should be planted in January. The reason is simple: get the plants in the ground while the earth is still warm and ahead of the rains, so that their roots can get established during the winter. This is the time-honored, water-saving way to plant that will result in a terrific burst of new growth come spring.
Choose plants recommended for your climate zone, and it’s best to group plants with similar water and sun requirements.
This is also the time to pull up the last remnants of summer vegetables and flowers and finish planting cool-season flowers and vegetables for winter and spring. Continue to cut back, clean out, plant, transplant and revamp perennials. It’s also the best time to plant most winter vegetables. Cool-season lawns can be seeded and, if you haven’t already done so, clean out the dead interiors of native plants, trim dead branches and shape plants in readiness for winter growth.
Prune & Divide
Divide, trim and mulch plants that grow in a clumps and that need to be divided, including bird of paradise, clivia, daylily, gazanias, fortnight lily, iris, Kahili ginger, lily turf and perennials like Shasta daisies. Hardy water lilies should also be divided and your geraniums: ivy, zonal and Martha Washington should be pruned back.
If you’re garden is bothered by rabbits, cats, dogs, opossums or skunks, sprinkle mothballs around the garden’s perimeter. They can’t stand the smell. If you have young children, substitute moth crystals, since mothballs are toxic and might be mistaken for candy.
(Excerpted from “Southern California Gardening, A Month-by-Month Guide,” by Pat Welsh. 2000.)