Piedmont Gardener

Northern Red Oak Tree Top

I’ve never paid much attention to Arbor Day until this year. I knew it was a day to celebrate trees and to encourage people to plant them. I knew I routinely get mail from the Arbor Day Foundation offering me “ten free trees” as a reward for becoming a member. And that was all I knew. So I did a little research.

Fringe tree: Chionanthus virginicus

Most states observe Arbor Day on the last Friday in April. Some southern states designate their celebration in January or February — better times to plant trees in the deep South. Some more northern states observe the holiday in late May for the same reason. In the United States, Arbor Day started with an early settler of the Nebraska Territory, J. Sterling Morton.  In 1872, when he created Arbor Day, Nebraska’s lands were being transformed from healthy prairies to farmlands. Native prairie ecosystems are relatively dry, soils are rich, and naturally occurring fires maintain the balance of species that comprise healthy prairie.

Purple Coneflowers are native to prairie habitats.

But when you plow up prairie to create farmland, soil erosion becomes a big problem. Those wide open spaces make it easy for strong winds to pick up huge masses of soil and blow them far away. Hard rains exacerbate erosion. Mr. Morton’s solution was to plant trees around fields to serve as wind breaks. He planted more trees to provide building materials and fuel, and to create shady spots during hot Nebraska summers. Morton grew into a prominent citizen over the years. He persuaded a lot of people to plant a lot of trees. Here’s a fact I didn’t know until yesterday: the Nebraska National Forest — all 141,864 acres of it — was entirely and deliberately planted by citizens of Nebraska. If you ever doubted that humankind can transform the Earth’s ecosystems, look no farther than the Nebraska National Forest — once prairie, now trees.

Native fall color left to right: American Beech, Musclewood, and Sourwood

I spent several hours on the Web site of the Arbor Day Foundation. This nonprofit sponsors a number of great programs. They help cities and college campuses promote and grow trees in their locations, they help people all over the world plant trees to improve their lives, they sponsor nature camps for children who otherwise see very little of the natural world, and they help replant our national forests after forest fires. In these cases, they appear to partner with local experts, for example, the National Forest Service partnered with them to replant fire-devastated forests.

Native Flowering Dogwood (Cornus florida)

But when the Arbor Day Foundation (ADF) sells trees to US citizens via their Web site, I think they are creating more problems than they are solving. Why? Because from what I saw — and I looked pretty thoroughly — the ADF makes no distinction between native and non-native trees in their offerings. Further, the “Tree Wizard” tool they provide to help folks figure out what kind of tree they should buy is inadequate. And finally, they do not reveal where they get the enormously diverse array of trees —  many not native to North America — that they offer for sale. This last bit is important, because the same species grown in a nursery in Wisconsin is much less likely to thrive in South Carolina. Even within a species, genetic diversity exists, and the genes selected for in a Wisconsin-grown tree are almost certainly not optimal for South Carolina growing conditions.

Where your Redbud was selected and propagated affects how it fares in your yard.

I worked through the Tree Wizard to see what trees it would recommend for my area. After it determines your hardiness zone, it asks what sort of tree you want. Your choices are: evergreen shrubs, flowering trees, ornamental trees, shade trees, evergreens, fruit trees, nut trees, and shrubs. Note that selecting only native plants is not offered as an option. I selected flowering, shade, and nut trees. Under “growing conditions,” the tool gives the following soil type options: all types, acidic, alkaline, drought tolerant, loamy, moist, rich, sandy, silty loam, well drained, wet, wide range, and clay. If you know anything about soil science, you know that not all of those choices are standard soil type options. What the heck is a drought-tolerant soil, for example? You can only pick one type here; I picked loamy. “Sun exposure” choices were all, full sun, partial shade, and full shade. Of course, any gardener with experience knows that in the southeastern US at least, the direction from which the sun exposure comes can be more important than the amount of sun. Some delicate understory native trees prefer morning sun and afternoon shade, for example. I picked full sun. The Tree Wizard next asks you to specify how tall and wide a tree you want, and what rate of growth you want. I picked all heights and all spreads, and all growth rates.

Southern Magnolia

The Tree Wizard displayed 11 pages of results. Its top choices based on my input were: White, Pink, or Red Dogwood, Redbud, Washington Hawthorn, Japanese Flowering Cherry, Kousa Dogwood, Saucer Magnolia, and Southern Magnolia. Most of these are actually native to North America, but the Tree Wizard doesn’t tell you that. Additionally, if you want a dogwood or a redbud to thrive in my region, you should never plant it where it receives full sun all day.

A thirty-foot tall kousa dogwood thrives in the shelter of our backyard, where the house shades it from searing afternoon summer sun.

Species names of the tree options are provided, which is interesting in itself. For example, both the Pink and Red Dogwood options are listed as Cornus florida var. rubra. I guess we’re just supposed to trust them regarding which color they send us. They appear to offer only species, no cultivars. For example, the Southern Magnolia they offer is described as likely to mature to between 60-80 feet, which is what the species does in its native environment. Frankly, I am disappointed in the Arbor Day Foundation. Clearly, they do a lot of good things, but when they aren’t partnering with local experts, they appear to blindly follow standard horticulture industry practices for selecting plants. Given the critical issues our native forests face, this is not good enough, especially for an organization that promotes itself as environmentally friendly. As it stands now, this organization — along with most of the horticulture industry in the United States — is actively encouraging plant blindness. They want you to believe that a tree is a tree is a tree. This is dangerously wrong. But the horticulture industry will not change unless its customers demand it from them. This is what I ask all of you who care about the future of our native ecosystems to do when you visit your local nursery, garden department, mail-order nursery, etc.:

• If the plant’s description does not tell you it is native to your region, ask the sellers its origin and why that information is not on the label. If they don’t know, tell them you’re not buying the plant — at least until you’ve had time to research it yourself. I’m not saying you must only buy native plants, but you do need to know an unfamiliar plant’s origins before you consider adding it to your landscape.

A non-native annual zinnia attracts pollinators without adversely impacting the health of your yard’s ecosystem.

• Know which species are considered to be invasive non-natives in your region. When you see them offered in your local nursery (and you will), ask the sellers why they offer plants known to be damaging to the local environment. Tell them you won’t ever buy such plants, and that you’ll be patronizing establishments that don’t sell such plants.

Native Joe Pye Weed attracts more diverse pollinators in my yard.

• If sellers cannot tell you more than what the label on the plant says, find another nursery where the staff is more knowledgeable. Unless the horticulture industry loses sales from promoting the notion that plants are interchangeable regardless of origin, they will not change.
• Work with plant sellers who grasp the concept of your yard as an ecosystem. If they can tell you which plants will work together to look beautiful and support native wildlife, patronize their businesses. Your yard is not your living room. Don’t pick plants as you might accessorize a room. Every plant in your yard is a vital, dynamic life form that interacts with every other life form on your property. Make your choices based on how the seasonal dance of life and color will look over time, not on the color of a flower today.

Native Plumleaf azalea blooms in mid-summer, providing a native source of food for local hummingbirds.

• Stop subscribing to gardening magazines that promote plant blindness and tell them why you’re stopping. “Gardens as rooms” is a decorator’s notion, and not relevant to the construction of vibrant ecosystems that we need to be creating to protect our planet’s future. Beauty can also be healthy, but health cannot be achieved via plant-blind choices.

I am happy to acknowledge that the Arbor Day Foundation is doing much good for the environment. Their failing is the failing of much of the horticulture industry. Its promotion of plant blindness — plants as completely interchangeable entities — must be stopped. Only we gardeners — this industry’s target market — can effect this change by directing our dollars to those businesses that  promote awareness of this increasingly critical issue. In my area, I can think of several wonderful locally owned plant nurseries that actively promote native plant gardening and ecosystem-appropriate designs. I can also think of several with inventories full of fancy non-native plants with unknown invasive potential, plants that must be coddled to thrive here, plants that don’t belong here.

Food gardens are easily integrated into a healthy landscape.

When you visit local nurseries, ask the hard questions. If you don’t get the right answers, tell them why you won’t be patronizing their establishments again. If we walk the talk, the horticulture industry will follow. Let’s get moving! Happy Arbor Day, ya’ll. And I promise to write about my gardens for the foreseeable future. 🙂