Building a home for good bugs

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Designing a garden to attract beneficial insects may seem simple, but the process is much more intricate than many think. When done right, however, what’s known as an insectary garden can help keep pests like aphids or mites at bay without having to use pesticides. Our market host Katie Hershfelt met up with Corey Welles, the plant health coordinator at the Montecito garden Lotusland, to learn about their newly planted insectary garden.

Photo: Kathryn Barnes (The original image is no longer available, please contact KCRW if you need access to the original image.)

“It’s nothing short of an urban model for habitat gardening,” said Welles about the garden he created alongside garden designer Eric Nagelmann. “All the plants have been carefully selected to attract beneficial insects,” including pollinators like native bees and insects that eat common pests, like aphids, mites, mealworms and scale insects.

“A lot of the good bugs are so small you can’t even see them with the naked eye,” he said, like the microscopic beneficial wasp. “They look like dust specks floating around, and they do the majority of the work for us. They can take care of whole colonies of pests, but they will only do it if you provide pollen and nectar. That’s where the flowers come in.”

Welles consulted with professors at UC Berkeley and UC Davis to decide on the right flowers and plants to incorporate into the garden. There’s a conscientious mix of native and nonnative plants like California Buckwheat, Ceanothus, Lupins, Poppies and Heliotrope. Most are planted in groups of up to fifteen, to create a massive home for beneficial insects.

Many farmers in Santa Barbara already use insectary gardens to keep pests at bay. “They know to dedicate some of their farm to habitat,” said Welles. Most row crop farmers dedicate every fourth row or so to annual flowers. Large farms and orchards often plant insectaries around the perimeter of their farming system.

One thing to remember, said Welles, is to maintain a balance.

“We actually want to keep some of those bad bugs in here, because if you don’t have pests, what are those young microscopic wasps going to lay their eggs on?,” he said.

The garden is in its infancy, right now, but just wait. Many of these plants will grow up to 5 feet tall when they mature. The bugs will love it.

Clockwise from top left: Heliotrope, Verbena, Sidalcea hickmanii and Phacelia campanularia. Photos: Kathryn Barnes (The original image is no longer available, please contact KCRW if you need access to the original image.)

Create your own insectary garden

  • Don’t worry about not having enough room. “The model is consistent across any size,” said Welles. Even a small apartment patio can host an insectary garden.
  • Plant 50-60% native plants
  • Keep a good ratio of annuals and perennials (these can even be grown in pots)
  • Incorporate a blend of chaparral, herbaceous perennials and annuals that bloom throughout the year
  • Stagger bloom times:
    • Spring: Poppies, Lupins, Sages, etc.
    • Summer: Buckwheat, Bluebeard, Cosmos, Lavendar, etc.
    • Fall: California Fuchsia, Toyon, Mountain Pennyroyal, Coyote Mint, etc.
  • Let some of your herbs bloom
  • If you have room, expand your insectary. “Insects evolved for economy of energy. If they see large groups of blooming plants, they’ll come back, reproduce and bring their friends.”