Salal (Gaulthera shallon) is an often scruffy Northwest native.

A few years ago, I didn’t care at all for native plants.

I thought they were ugly and boring, and I didn’t understand why any gardener would want to plant them, when there are so many other, prettier plants we can grow from all over the world.

I live in Portland, Oregon—Zone 9a. Our winters are as mild as Pensacola, Florida’s, on average, but we have none of the humidity in summer. We can grow anything! Why would I possibly want to grow our scruffy Northwest natives?

I didn’t think native plants were important for wildlife.

I saw bees and birds in my garden. I figured my exotic plants were giving them everything they needed. Besides, if some wildlife did rely on native plants, well, that’s what nature’s for, right? My garden was for me, for my own pleasure. I didn’t appreciate native plant evangelists telling me what I should and shouldn’t plant. My garden was my sanctuary.

And then, in December of 2020, I read Doug Tallamy’s book, Nature’s Best Hope.

I didn’t want to read it. I’d read Tallamy’s previous books on gardening for wildlife, and they didn’t move me. But, I was on a book award committee, and Nature’s Best Hope was a candidate on the list. I had to give it a fair shake.

It completely changed my worldview.

There were four statistics in the book that were key to changing my mind, and they had to do with caterpillars.

Statistic #1: Ninety-six percent of terrestrial birds in North America feed their chicks insects—rather than seeds or berries—and the insects they choose are primarily caterpillars. In our backyards, doves and finches can get by on seeds, but pretty much all other birds need caterpillars. They’re essential for baby birds.

baby birds

These baby finches can eat seeds, but most chicks need caterpillars.

Statistic #2: Well, how many caterpillars do birds need? The answer: thousands. For example, in one study, over a span of 16 days, one pair of Carolina chickadee parents, on average, brought their offspring 6,000 to 9,000 caterpillars.

I couldn’t get my head around those numbers, so I did the math. On average, each parent brought 3,750 caterpillars to the nest over that 16-day period. That’s 234 caterpillars per day and 16.7 caterpillars per hour if they worked from 6 a.m. to 8 p.m. That means each bird brought one caterpillar every 3.6 minutes. Since birds often bring more than one caterpillar per trip, each bird made about one trip to the nest every five minutes for 14 hours a day.

Gives new meaning to the phrase, “eat like a bird.”

Statistic #3: Eighty-six percent of caterpillars are specialists, which means they can only eat plants belonging to three or fewer families. Two-thirds of caterpillars can only eat plants from one family. Nearly half can only eat plants from one genus. We all know monarchs can only eat milkweed, but that kind of relationship is not unique. Most caterpillars are on a highly restricted diet.

Yes, but do they have to eat native plants in those families/genera?

Not always, but most of the time, yes, they do. Caterpillars have to eat the plants they’ve evolved with. They’ve developed ways to deal with the toxins produced by certain plants, and most of them have come to rely on those plants exclusively.

Exotic plants may feed a few caterpillar species, but they don’t make any meaningful contribution to food webs. Heck, even most native plants don’t make a huge contribution to food webs. Only about five percent of native genera feed 70 to 75 percent of our caterpillars.

Tallamy calls these heavy lifters “keystone plants.” Keystones vary by region, but in most of the country, plants like native oaks, willows, cherries, maples, and poplars top the list.

Statistic #4: Well, can’t insects just live in nature and leave our gardens alone?

Not really, because as Tallamy points out, “Ninety-five percent of the country has been logged, tilled, drained, grazed, paved, or otherwise developed.” There isn’t enough pristine “nature” left out there for wildlife.

We’re in the midst of our sixth mass extinction, and there’s nowhere for wildlife to go. We have to make our developed areas more amenable to wildlife—in particular, to insects—if we want to support the food webs that sustain life on our planet. The whole world is a garden now, and we must replace the keystone plants we’ve lost.

Ecological wasteland

The whole world is a garden, and this is what much of it looks like.

The news shook me.

Have you ever had a big change of heart about something that was important to you? It rarely happens—even among people who consider themselves open-minded—because it’s painful. When we learn something that contradicts a belief we hold dear, we experience cognitive dissonance, and it’s uncomfortable. Our brain immediately looks for reasons to discredit the contradictory information, because that’s way easier than changing the belief. Humans are hardwired to stay the course.

I started out in horticulture in the ’90s. I learned early on that native plants can be nice, but exotic plants cherry-picked from around the globe make for a much more exciting garden. I wanted to grow ALL THE PLANTS. And I did!

I was always able to dismiss the idea that natives should get higher billing in my garden, and the idea that natives should make up the majority of my garden was laughable.

Until I read Nature’s Best Hope. The evidence was irrefutable. Leaf-eating insects need native plants to survive, and those insects, in turn, form the basis of food webs around the world. Natives are necessary.

No longer able to easily dismiss the evidence conflicting with my belief, I accepted the discomfort. I sat with it. Change didn’t happen overnight. It took me a couple of months to process the information.

When I got to the other side, I looked at my garden differently. I looked at my neighborhood differently, and the world in general. I saw plants everywhere that were essentially worthless to wildlife, and it broke my heart.

I went to work on my garden.

I tore out plants that didn’t feed anybody, and I replaced them with plants that did. I planted northwestern keystones like Scouler willow, Garry oak, chokecherry, white alder, and vine maple. I researched Northwest native pollinator plants and planted goldenrod, pearly everlasting, gumweed, checkermallow, camas, snowberry, waterleaf, Oregon grape, and lupines.

I added habitat. I put in a pocket prairie and a tiny pond. I brought in some old logs for the beetles. I left the leaves where I could. I left bare ground for ground-nesting bees, and I cut my perennial stems long for stem-nesting bees. I let the grass grow long along the fringes.

wildlife garden

My garden welcomes wildlife.

Over the past few years, I’ve watched. I’ve walked the garden. I’ve taken thousands of photos. And I’ve been blown away. I’ve been blown away by the diversity of insects I’ve found in my garden.

In just the past three years, I’ve observed about 300 species of insects. I’ve posted over 800 observations to iNaturalist, a citizen science website. Every day brings new discoveries. Every day brings drama and surprise. I’m filled with a sense of wonder every single time I step foot in the garden.

western tiger swallowtail

A western tiger swallowtail butterfly, from an egg laid on my Scouler willow.

Now, I can’t imagine gardening any other way.