Conservation Biological Controls: Guardians of the Garden

Plants which support conservation biological control attract insect predators. This is so important for ecosystem balance, can save your vegetable garden from being devoured by pests, protect your native flowers and berries so the birds can feast (and flock to your yard), and keep out invasive non-native pests such as Spotted Lantern Fly. (See more in this Facebook post).

Tiny Native Flowers are the Key

Native wildflowers with tiny flowers are the key, according to Heather Holm! Flowers such as yarrow and milkweeds and dogwoods (the dogwood shrubs such as Cornus amomum, Cornus racemosa, etc. have tiny composite flowers).


Cornus amomum, Silky Dogwood shrub. Photo by SB_JohnnyCC BY-SA 3.0, via Wikimedia Commons.
By the way, Birdscaper Tim Mack says the birds LOVE Silky Dogwood berries! Photo by Douglas GoldmanCC BY-SA 4.0, via Wikimedia Commons.


Note: Some yarrow is not native and behaves in a very aggressive invasive fashion. Some yarrow is native and grows quite politely, if resiliently, alongside others. It is apparently very difficult to tell the difference between the two without DNA analysis. But behavior can provide clues. I have what must be native yarrow volunteering on our property and have collected seed.

Calico Asters

Now that we don’t mow all the time, I’ve got many more tiny-flowered natives volunteering from the wild including Calico Aster (Symphyotrichum lateriflorum), which says supports conservation biological control. My first volunteers are blooming right now. The foliage is much much denser and darker than S. pilosum (White Old Field Aster), and it has tiny white flowers with pinkish rusty centers, blooming densely despite severe browsing by the goats, and not at all showy. But now that I know it supports ecological balance, I’m even more happy with them. Even Michael noticed them and remarked on them (I think people have an instinct about these things, even when they don’t *know* about them). He spared one from mowing and this morning I observed a party of wasps foraging on the flowers.


The spring-blooming Erigeron philadelphicus, Philadelphia Fleabane, and Erigeron annuus, Daisy Fleabane, are also said to support conservation biological control and I loved E. philadelphicus this spring especially for its very long bloom period and pinkish flowers. Right now, everywhere that I let them bloom and go to seed, there are dense rosettes, preparing for next spring’s shoot up to full height and bloom.

Wildflower Wednesday’s Conservation Biological Control Species

From this year’s Wildflower Wednesday giveaways, the following plants support conservation biological control (detail provided by Xerces Society’s “Habitat Planning for Beneficial Insects”):

1. Zizia aurea, Golden Alexanders: Flies, parasitioid wasps, lady beetles, soldier beetles

2. Coreopsis lanceolata, Lanceleaf Coreopsis: Syrphid flies, solitary wasps, beetles, assassin bugs

3. Monarda punctata, Spotted Bee Balm: Solitary wasps, flies, beetles

4. Asclepias tuberosa, Butterfly Milkweed, Asclepias incarnata, Swamp Milkweed, Asclepias verticillata, Whorled Milkweed: Highly attractive to numerous beneficial insects.

5. Pycnanthemum tenuifolium, Narrow-leaf Mountain Mint, 6. Pycnanthemum virginianum, Mountain Mint: Solitary wasps, flies, beetles

6. Solidago odora, Anise-scented Goldenrod, Solidago speciosa, Showy Goldenrod, Solidago rugosa, Wrinkle-leaf Goldenrod, Solidago caesia, Wreath Goldenrod: Highly attractive to numerous beneficial insects.

7. Symphyotrichum lateriflorum, Calico Aster

8. Lobelia siphilitica, Great Blue Lobelia

9. Heliopsis helianthoides, Oxeye Sunflower

10. Agastache nepetoides, Yellow Giant Hyssop


Habitat Planning for Beneficial Insects (Xerces Society pdf)

Erigeron philadelphicus at

Symphyotrichum lateriflorum at

Katy Morikawa
Katy Morikawa