By Christine Hoey, Co-chair of the Native Garden Committee and a native plant enthusiast
Summertime is fast approaching, and you may be wondering how to make your vegetable and fruit garden more productive. Hands down, the answer is to create a California native habitat nearby. Native plants and trees attract pollinators such as bees, birds, butterflies, hoverflies, wasps and more, which in turn pollinate your fruit trees and vegetables. Research shows that a biodiverse native habitat next to a food garden, can increase crop production by 18 to 71% depending on the crop (Bartomeus et al., 2014). This means more than enough fresh produce for you with extra to share!
Create a Native Habitat and They Will Come
Attracting pollinators and pest predators to your food garden is not hard to do as long as you provide shelter, food (nectar & pollen) and water. According to the Xerces Society, planting native trees, shrubs, perennials, and annuals for season-long bloom (March - October) provides all the above. Trees and shrubs give birds a place to shelter and nest, whereas solitary native bees prefer nesting in tree cavities, hollow plant stems or even burrowing underground. Leave a patch of bare soil for underground dwellers or hang a simple ‘Bee Hotel’ facing east to give native bees a place to call home.
Vegetable gardens and fruit trees are also a good source of pollen and nectar for your pollinators. Allowing leafy vegetables to bolt (like lettuce) supplies an additional food source for bees.
Water source: Birds appreciate bird baths for bathing and drinking. The above photo shows a creative way to provide fresh water using a dripper system. Birds have even been seen drinking directly from the dripper! Bees prefer a shallow bowl filled with pebbles to rest on while sipping water. Butterflies, moths, and bumblebees are also attracted to moist soil and mud puddles for their daily minerals to stay healthy.
Pollinator Stars and the Food Plants They Pollinate
Bees: According to biologist and native bee expert James Hung, Ph.D., there are over 600 native bee species in San Diego County. Native bees are mostly generalist pollinators, but a few can be very particular, like squash bees (Peponapis pruinosa) that are only attracted to melons, squash, and pumpkin blooms.
Some bees are better than others at pollinating food gardens. For instance, the California Bumble Bee (Bombus californicus) and Yellow faced Bumble Bee (Bombus vosnesenskii) are very effective at pollinating tomatoes & eggplant by vibrating the pollen loose. Native bees are attracted to peppers, squashes, gourds, watermelons, cucumbers, strawberries, blackberries, blueberries, apples, beans, cane berries, fruit trees including apples, pears, stone fruits, almonds, avocados, artichokes, and persimmons.
Butterflies and Moths: Calscape lists 142 butterflies and moths that call San Diego home such as the Monarch (Danaus plexippus), Smith’s Blue (Euphilotes enoptes smithi), Pale Tiger Swallowtail (Papilio eurymedon), Common Checkered-skipper (Pyrgus communis), and Dotted Blue butterflies (Euphilotes enoptes). They prefer open areas and large stones around the food garden where they can rest and catch a little sun. Less efficient at pollinating than bees, butterflies and moths passively pass pollen from flower to flower as they feed on nectar. They are attracted to flowers that are brightly colored and large enough to perch while dining on nectar.
Beneficial Flies: Hoverflies not only pollinate the garden, but their larvae will feed on aphids, leafhoppers, and other garden pests. They are attracted to avocados, peppers, strawberries, cane berries, grapes, peaches, almonds, pears, apples, cashew, fennel, caraway, beets, carrots, and celery.
Birds
Hummingbirds are the main pollinators in the avian world. They are very efficient in drawing nectar from tubular flowers but will visit any flower with nectar. They also eat larvae, insect eggs, spiders, mosquitoes, gnats, aphids, and other small insects. They are attracted to groupings of colorful flowers such as California Fuchsia (Epilobium canum) and Chaparral Currant (Ribes malvaceum). They don’t depend on drinking water but appreciate birdbaths and sheltered perches for resting.
Designing Your Food Garden in Zones
Think of your food garden as the center of your design plan, then plant outward with native plant zones grouped according to water needs. For example, water tolerant natives should be planted closest to the garden. As the zones move away from the center of your plan, native plants should be planted according to decreasing water needs.
Calscape will help with your search by typing in your zip code or address. This will create a list of California natives indigenous to your area. The “Advanced Search” button lets you select the desired plant characteristics you are interested in. The native plant list below is an example of using the Calscape advanced search option for San Diego. My search options included ‘bee, bird, butterfly, hummingbird gardens and butterfly host plants.’ Water requirements were adjusted according to the zone number in Diagram 1 below.
Diagram 1: Food Garden Native Plant Zone Map
Zone 1: Closest to the garden beds along the outside edge of pathways surrounding the food garden, plant more sun and water tolerant native plants like California Grape (Vitis californica), California Wild Rose (Rosa californica), Western False Indigo (Amorpha), Yerba Mansa (Anemopsis californica), Scarlet Monkeyflower (Erythranthe cardinalis), Western Columbine (Aquilegia formosa), California Buttercup (Ranunculus californicus), Alkali Heath (Frankenia salina), Narrow Leaf Milkweed (Asclepias fascicularis), Pacific Blackberry (Rubus ursinus), and Douglas Sagewort (Artemisia douglasiana).
Zone 2: Next to the water tolerant natives or “transition plants” go Spice Bush (Calycanthus occidentalis), Douglas Iris (Iris douglasiana), Common Yarrow (Achillea millefolium), Bush Anemone (Carpenteria californica), California Fuchsia (Epilobium canum), California Honeysuckle (Lonicera hispidula) and Bladderpod (Peritoma arborea).
Zone 3: In this zone, choose from drought tolerant natives such as Sages (Salvia spp.), Buckwheats (Eriogonum spp.), Sawtooth Goldenbush (Hazardia squarrosa), Dwarf Coyote Brush (Baccharis pilularis ‘Pigeon Point”), San Diego County Viguiera (Bahiopsis laciniata), Showy Penstemon (Penstemon spectabilis), and White Flowering Currant (Ribes indecorum).
Zone 4: And last, place the most drought tolerant natives like Manzanitas (Arctostaphylos spp.), Scrub Oaks (Quercus berberidifolia), Ceanothus, Lemonade Berry (Rhus integrifolia), Spiny Redberry (Rhamnus crocea), Catalina Cherry (Prunus ilicifolia), and Toyon (Heteromeles arbutifolia) in Zone 4.
Don’t forget to add annual wildflowers such as Clarkia (Clarkia unguiculata), California Poppies (Eschscholzia californica), Lupines and Tidy Tips (Layia platyglossa) as additional food sources and to add a pop of color in your garden. Creating a biodiverse native habitat around your vegetable garden and fruit trees provides so many benefits for your garden and for your garden “helpers” too - just remember they need shelter, food, and water just like we do!
Christine Hoey is co-chair of the Native Garden Committee and a native plant enthusiast.
Resources & References:
https://crownbees.com/ - For more information on purchasing native bees and bee homes for your garden.
Pollinator Network Selecting Plants for Pollinators A detailed guide for the California coastal, chaparral forest and shrub.
Xerces Society resource on native plants that attract beneficial pollinators for our region.
Calscape - CNPS website with a comprehensive catalog of California native plants, where they grow and where to purchase plants for your landscape.
Tree of Life Nursery PDF Guides you may be interested in:
“Planting Guide” for natives PDF: Planting Guide
Native plant options to replace traditional ornamental plants PDF Plant Respecifier
“Fantastic Fungi: The Magic Beneath Us” - documentary film directed by Louie Schwartzberg takes you on a “journey of mycorrhizal network that can heal and save our planet.” Available for rent on Apple TV, Amazon Prime, Google Play and https://fantasticfungi.com/
Bartomeus, I., Potts, S., Steffan-Dewenter, I., Vaissière, B., et al., 2014. Contribution of insect pollinators to crop yield and quality varies with agricultural intensification. PeerJ 2, e328 (10.7717/peerj.328).