Garden insects: how to attract the good ones

Written by Katherine, Landscape Design Associate

Have you heard the term “insectory plants?”  These are plants that attract certain kinds of beneficial insects.  Now what’s a beneficial insect?  They mow lawns, take out my trash, and tell me I’m pretty, right?  Not really, but their unabashed pest-consumer lifestyle will surely keep your plants looking healthy!

Let’s walk through some of the top “insectory plants,” and keep in mind that the flower holds the true power for attraction.  Lacewing, Ladybeetle, Hoverflies, Parasitic Wasps, Predatory Mites, and Minute Pirate Bug come hither! 

Carrot Family

Also known as Umbelliferae or Apiaceae, the Carrot family includes annual, biennial, and perennial herbs with an umbrella-shaped flower form that look something like:

Herbs such as Parsley, Cilantro, Dill, Fennel, and the vegetable Carrot (of course) are grouped in this family.  When these herbs are left to flower they support a variety of beneficial insects.

Mint Family

Also known as the Lamiaceae family, the Mint Family includes aromatic flowering plants often used as culinary herbs.  An example:

Basil (all types), Mint (of course), Catnip, Lavender, Rosemary, Sage, Thyme, Marjoram, Za’atar, Cuban Oregano and Oregano are some examples.  Like the Carrot Family herbs, Mint Family flowers are the ticket to attracting a slew of top-shelf predatory insects! (Fun fact: you can often ID a plant in the mint family by it’s square stem).

Daisy Family

Also known as Asteraceae, Compositae, or Sunflower family, plants of this grouping have disc-shaped flower heads which are composed of a cluster of many smaller flowers.  For instance:

Cosmos, Zinnia, Marigold, Calendula, Sunflower, Gaillardia, Dandelion, Chrysanthemum, and Okinawan spinach are together in this family.  And they are beloved by predator insects for their generous pollen and nectar offerings!

Native Hawaiian Plants

In the realm of novel partnerships, native plants serve an important role in attracting beneficial insects.  It turns out many species of Ladybeetle thrive among native Hawaiian plants:

A’ali’i, Mamaki, Akia, Ilima papa, and Uhaloa are host plants for beneficial predator insects.

Vegetables (with a side of pest-fighting protein!)

Zucchini, Cucumber, Pepper have an ability to produce food for us and attract garden allies.

Cover crops and Fruit Trees

Have you noticed a trend here—plants serving multiple roles?  Cover crops which are often planted in fields for erosion control and to restore nutrients to the soil also do the job of attracting beneficial predator insects.  Fruit trees are another plentiful source of pollen and nectar.

Cover crops include Buckwheat, Sunn hemp, and Crimson clover.  Fruit trees such as Papaya, Citrus, Lychee, Avocado, and Mango all help attract beneficial predators.

Ti plants and Crown Flower

Ti is in the Cordyline or Asparagus plant family, and is a host plant to Ladybeetles.

Crown flower is in the Apocynaceae, or Milkweed family, and provides a rich source of pollen and nectar for beneficial predators.

Conclusion

If you can keep a patch of some insectory plants in your garden, it will greatly reduce the impact that pests have on your plants.  For example, one ladybeetle larvae can eat up to 400 aphids in a day, and an adult ladybeetle will eat up to 5,000 in its lifetime! 

This chart shows some common pest-predator relationships in Hawaii:

So by attracting these beneficial predators, your plants will have some protection to stay healthy and pest-free!

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