Gardener’s Notebook by Joshua Burman Thayer
As the first rains dapple the landscape, there’s new opportunity to expand your home garden with productive food plants. Here in Northern California you get the advantage of continued growth throughout our wet-cool season with the following evergreen plants, which can continue to develop all winter long.
Originating in the sub-tropical areas of Asia, citrus plants love our mild Bay Area winters. Plant lemon (citrus limon) for juice used in any cooking application, citron (citrus medica) for its flavorful zest, and mandarin (citrus unshiu) for eating fresh. If you’re in a part of the East Bay that gets colder winter temperatures, you can still plant kumquat (citrofortunella). I have good plants fruiting as far east as Danville and Livermore. Mandarin is also quite cold hardy.
When planting, space your trees 10 feet apart. Citrus likes rich, fluffy soil, so planting in raised mounds 12 to 24 inches tall works best. I add a calcium-magnesium enriched organic soil food into the bottom of the planting hole, and then also feed each citrus tree twice a year with a top dressing of calcium-magnesium.
Persea americana originated in the tropical highlands of Mesoamerica, and it loves growing here in the East Bay. Given the right conditions, home avocado trees can provide a cost-effective home-grown protein. Hass is the classic, but also consider Bacon, a cold-hardy cultivar. By planting two types you boost pollination.
Plant your trees 20 feet apart. Avocado likes rich, fluffy soil, so planting in 12–24-inch-high raised mounds works best. Because avocado plants are heavy feeders, I add a calcium-magnesium organic soil food and 1/3 bag finished compost to the bottom of the hole and then also feed each tree twice a year with a top dressing of calcium-magnesium.
Olea europea is a tough and mighty plant that can live thousands of years and has provided humanity with oil, food, and light through the ages. These trees thrive in our dry-summer Bay Area climate.
Mission olive is a classic Californian cultivar that provides good oil and good fruit. Mauro, a heavy bloomer, can be utilized as pollination support for your mission trees. Space your trees 15 feet apart. Olive likes rich, fluffy soil, so planting in 12–24-inch-high raised mounds works best. Because olives are light feeders, you only need to add a quarter bag of finished compost to the bottom of the planting hole. I also feed each olive tree twice a year with a top dressing of worm castings.
It’s always a good idea to mulch with wood chips, grass clippings, hay, or cocoa hulls around your entire property to protect your soil through the winter’s rains. Mulch will also insulate and keep your young trees’ roots warm.
Evergreen Edible Understory
Add understory plants to hold the soil and bolster your garden’s biodiversity. Mint (Mentha spp.), rosemary (salvia rosemarinus), and oregano (Origanum vulgare) are all winter bloomers and all help dissuade rodents.
Consider planting nopal cactus (Opuntia ficus-indica) if you want a perimeter fence that also provides good edibles with its nutritious pads and tasty fruits.
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