This spring, inspired by Jessica
Walliser’s Attracting Beneficial Bugs to
Your Garden, I’m planting an insectary bed, and it’s turning out to be a
blast.
The
idea is to devote an area of the garden to plants that provide forage, nectar,
or reproductive quarters for native insects, which in turn will help me out by
pollinating my flowers and vegetables and keeping leaf-eating competitors in balance. Working from Walliser’s list and the plants recommended by George Adams
in Gardening for the Birds, I’ve so far
planted native perennials yarrow (Achillea
millefolium), swamp milkweed (Asclepias
incarnata), bluebell (Campanula
rotundifolia), purple coneflower (Echinacea
purpurea), oxeye sunflower (Heliopsis
helianthoides), garden phlox (Phlox paniculata 'David'), and two New England asters
(Symphyotrichum novae-angliae). For
annuals I chose cosmos and sweet alyssum, with sunflowers and zinnias to come. Under
lights in my kitchen I grew a bunch of black-eyed Susans (Rudbeckia hirta) from seed and popped those in around the edges of
the bed. I also started monkey flower (Mimulus
‘Magic Blotch’) for the first time and was amazed to see the seedlings
flowering about three weeks after I’d planted the seed. I hope they’ll keep it
up through the summer.
Newly planted monkey flower |
We
were all sold a bill of goods during my childhood in the fifties and sixties by
the makers of garden chemicals. When I started gardening, I had the idea that
just about all insects were bad. I liked butterflies and ladybugs, which got
good press and didn’t seem scary. My basic paradigm, though, was Gardeners
Good, Insects Bad, Plants Defenseless. Now I learn from Doug Tallamy and others
that this was all wrong, as well as a vast over-simplification. It turns out
that the insect component of a garden ecosystem involves a complicated system
of checks and balances, and plants are active players, sending out signals all
the time that influence the insects and microbes around them.
Reading
Tallamy’s Bringing Nature Home woke
me up. He argues convincingly that we humans have taken over almost all the
land in the United States and covered it with nonnative vegetation, as well as
pavement and buildings. That means there’s little forage or habitat left for
the native insects we depend on at the base of the food web that allows us all
to eat. I’m not ready to pull out all the nonnative plants in my garden, but
I’ve resolved to choose natives whenever a space opens up. My insectary garden
is part of this effort. Walliser and others point out that native insects
benefit from some nonnative plants, especially as sources for nectar. That’s
why I feel OK including zinnias, which originate in Mexico, and an edging of
sweet alyssum, which came to us from southern Europe.
The space I'm planting with these insect snacks is part of my designated vegetable-growing area. The half that gets the most sun will still be for edible-podded peas, salad greens, tomatoes, cucumbers and green beans. The other half I’d
half-heartedly used as a nursery bed, sinking pots of self-seeded bleeding
heart and columbines and divided Siberian irises that I was saving for the PTO
plant sale. I have to admit that it got infrequent weeding and looked like
quite a mess by the end of last summer (Walliser actually recommends keeping
certain weeds for the bugs—I can claim that’s what I was doing).
I’m
finding it surprisingly liberating to choose plants for the insectary bed
without worrying about a color scheme. This time it’s not about good taste,
it’s about tasting good. When I see the garish flower combination that ensues,
I’ll probably change my mind and want to revise. Watch this space.
I wonder if patience is my strongest ally in coping with pest insects. In one of my early years growing hops, there was a horrible infestation of aphids. They haven't been back in subsequent years. I don't know if it's weather or build-up of predator insects or resistance compounds in the plants, but whatever the forces involved, they were much more effective than any anti-aphid measures (like mild soap and water washing) I've tried on other plants...
ReplyDeleteI'm sure you're right. One point I've had trouble remembering is that some prey has to be present to support a population of insect predators. So I'm wrong to go on the attack too quickly. Do you think plants develop resistance to particular herbivores over time?
DeleteI love your summary of the traditional paradigm: Gardeners Good, Insects Bad, Plants Defenseless! I have been amazed at how little permanent damage bugs do on my land, although I am not aiming to produce vegetables.
ReplyDeleteI have been trying to reframe my reaction to insects and delight in seeing new species as signs that my garden is supporting diversity. I try to catalog the bugs I find by drawing and observing them, but I lack the science knowledge to classify insect species. Fortunately I found Project Noah (www.projectnoah.org/), which is a web tool created by NYU "to explore and document wildlife and a platform to harness the power of citizen scientists everywhere." One night at about 11 p.m. I uploaded a photo of a mysterious small brown bug to Project Noah and by the time I awoke in the morning I had two messages with identification - one from a friendly middle-schooler in the U.S. Southwest and another from a graduate student in Panama!
Thanks for this tip about Project Noah. I realize that I can't identify almost any insects and probably don't see 99 percent of them because I don't know enough to look for them. For example, I just noticed vast numbers of protective shells of scale insects lining the stems of my kiwi vine; surely they didn't just appear yesterday, but I wasn't looking. It would be great to learn more about insects.
DeleteThe realization of the ways in which insects can be indispensable to the vitality of a garden is great! Also, the functional balance that you found between native and non-native plants is encouraging!
ReplyDeleteGood to hear, especially coming from an environmental scientist
Delete