The Loma Prietan - January/February 2009

Gardening Green

"Bulk Up" Your Garden this Winter

story and photo by Arvind Kumar

This bioswale, planted with native sedges and rushes, collects water during rainstorms and filters out pollutants.
This bioswale, planted with native sedges and rushes, collects water during rainstorms and filters out pollutants.

If you have lived in California for any length of time, you know how different it is from the East Coast or Midwest or northern Europe. California is warm and dry for the better part of the year, with not a drop of rain for eight months. All our water comes from the sky during the four short months of winter. Our environment is rooted in this winter-wet, summer-dry cycle. For our plants, winter is the time for rapid growth and regeneration; summer is the time for dormancy.

Those who ignore this fundamental reality do so at great cost to themselves and the environment. Those who recognize this reality and turn it to their advantage eventually succeed and thrive. Successful California gardens are designed to absorb the winter moisture, "bulking up" naturally and organically in order to survive the dry season ahead.

What can you do to help the garden bulk up this winter so it will be more vibrant and resilient the rest of the year? Here are some tips.

Plant natives: Native plants are naturally adapted to our climate and soils, have unmatched habitat value, and are beautiful in their own right. This is the best time of year to plant them. Want ideas? Visit your local library or bookstore and get a copy of California Plants for the Garden, by Bornstein, Fross, and O'Brien.

Mulch: Any organic matter spread over the ground helps control weeds, retain moisture, and enrich the soil over time. Instead of using toxic herbicides, incorporate a two- to four-inch layer of wood chips in plant beds. Ask for free chips from your local tree service company.

Leave the litter: Allow leaf litter to decompose in place, an easy way to return nutrients to the soil and help rebuild top soil that was lost to bulldozing and grading.

Compost: Spread compost to add organic matter and nutrition to the soil and to improve its capacity to absorb and hold moisture. Start a compost pile, if you don't have one.

Reduce run-off: Build a bioswale, a shallow, level depression in which rainwater can collect and slowly percolate through the soil to recharge aquifers. Plant it with water-tolerant plants such as rushes and sedges. In hardscape, use permeable materials such as decomposed granite and porous tiles, so water can seep through instead of running off.

Plant wildflowers: Start wildflower patches in your garden for seasonal color and year-round habitat. Keep the patches small and clear of mulch; hand weed as necessary. Clarkias, poppies, and gilias will germinate and fill these spaces with color in spring. Birds will feast on the seeds all year long. Once established, a patch will regenerate on its own year after year.

Control pests: During winter, snails and slugs emerge from hibernation and devour tender seedlings at a mind-boggling rate. Control the pests by hand picking at night or early in the morning; persistent picking is extremely effective. Use copper tape barriers, or a nontoxic bait such as Sluggo or beer.

Weed: Pull water-gulping weeds before they go to seed. Pay attention to the shape of leaves and flowers; with time you will be able to tell weed seedlings apart from the garden plants. With mulching and regular weeding, you can reduce the weed population in your garden.

Dig up invasives: Plants like pampas grass and ivy have outlived their welcome in California. Winter is a good time to dig these invasives up and dispose of them. They have done tremendous damage by invading California's wildlands; do your part to control them and educate your neighbors.

As you take these steps, one by one, your garden will become more resilient and sustainable, thriving during California winters and better able to survive the long summers.

Sierra Club life member and California Native Plant Society director Arvind Kumar grows native plants in his Evergreen garden. He can be reached at