Homegrown: How to lure pollinators into your Sonoma County vegetable garden

The alarming decline of the honeybee population isn't a predicament only for almond growers in the Central Valley. All of us depend on bees and other insects to pollinate food crops, whether they be on monster agribusiness acreage or in our own backyards.

It is estimated that pollinators are responsible for at least a third of what we eat every day. If we depend on food grown year-round in our home gardens, that percentage could be even larger.

Tending a bee hive that will bring pollinators into our gardens isn't for everyone, but anyone with available outdoor space can host a bee hive. A hive management service or the Sonoma County Beekeepers' Association (sonomabees.org) can offer assistance.

Most gardeners, however, trust they can attract bees and other pollinators that include butterflies by luring them with showy, pollen- and nectar-rich plants. Showy is a key concept, since nearly all vegetable flowers are rather ho-hum and don't attract adequate numbers of pollinators as easily as do most ornamental flowers.

But a bountiful harvest in the food garden depends on more than simply encouraging an occasional visit from pollinators. They must return consistently throughout the growing season.

Keeping a constant flowery show going may seem like an arduous task, but that's what a good many annual and perennial flowers do - bloom their heads off for months. The solution is selecting several species that bloom on cue in every season.

Pollinator favorites

If you're concerned that only native plants will attract pollinators, rest assured that isn't the case. California natives most definitely attract bees, but non-native honey bees visit an even broader spectrum of species.

Some of the most popular landing spots for small insects are flowers with tiny blossoms crowded together in flat clusters such as those in the center of asters, zinnias and sunflowers. But there are many others.

Rather than harvest all carrots, radishes and parsley, some gardeners routinely allow a few to develop a flower stalk and blossom. Their small flower clusters are favorites of bees and other beneficial insects.

Herbs like borage, rosemary, oregano, lavender and sage are well-loved by bees. They flower many months of the year and are pleasing combinations with vegetables. Mint is another candidate, but because it is such a rampant spreader, plant it only in pots, never in the ground, and set pots within beds.

Flowers for interplanting

Many pollen- and nectar-rich ornamentals such as multi-hued snapdragon and verbena hybrids can be planted within or between rows, or scattered throughout a vegetable patch to attract bees.

Marigolds, coreopsis, bidens and calendula enliven trailing vines of cucumbers and squashes with bright, golden yellow blooms as they lure pollinators. Low clumps of white sweet alyssum create enticing displays in front of tomatoes and salad greens.

Blue blossoms are among the most visited by bees in any garden, but few are suitable within vegetable beds. Low tufts of ageratum and taller scabiosa and cornflowers - also called bachelor's buttons - are welcome additions.

Flowers nearby

Although newer cosmos cultivars are low-growing and are appropriate inside vegetable beds, most are as much as 5 feet tall and are better planted around the perimeter.

Verbena bonariensis, sunflowers and Russian sage (Perovskia) can soar to 6-foot heights and also are best planted outside the borders of vegetable beds.

Another group of showy flowers valued for their pollen and nectar develop wide-spreading branches and roots. They compete too vigorously with food plants and are best planted somewhat beyond the edible garden.

These include seaside daisy or beach aster (Erigeron glaucus Wayne Roderick), purple cone flower (Echinacea), sea holly (Eryngium), yarrow (Achillea), bee balm (Monarda), black-eyed Susan/gloriosa daisy (Rudbeckia), sweet Williams (Dianthus barbatus), butterfly weed (Asclepias), catmint (Nepeta), various sages (Salvia), ceanothus and bluebeard (Caryopteris).

Helpful hints

Keep in mind that it takes not just an isolated plant or two to attract pollinators but a sizeable group that bees and other beneficials can locate from a distance.

Most vegetables and showy flowering annuals and perennials must be located in sunny sites to be productive.

But a few crops, such as lettuce and other greens, prefer shade during the hottest months and hours of the day. For these, select bloomers such as snapdragons and sweet alyssum that tolerate some shade.

In addition to planting showy flowering plants around orchard trees, place nesting boxes nearby to attract mason bees for pollinating spring blooms.

Rosemary McCreary, a Sonoma County gardener, gardening teacher, and author of Tabletop Gardens, writes the monthly Homegrown column for The Press Democrat. Contact her at rosemarymccreary@gmail.com or write to her at 427 Mendocino Ave., Santa Rosa 95401.