This year I’ve been faithfully following a new custom, a weekly inventory of what’s blooming in the garden. It’s turned out to be surprisingly satisfying. I do this to find out whether pollinators have flowers to visit in the yard throughout the growing season. It turns out they do, but I’d like to tweak the types of flowers they find. Now nonnatives often dominate.
This beautiful ornamental plum blooms early, but it's not a native
For example, in March, witch hazel, crocuses, cornelian cherry (Cornus mas), snowdrops, and vinca bloomed. Those were welcomed by foraging bumblebees emerging from their winter nests in the ground. But none were native plants.
At this point, I’m prioritizing natives when I bring in new plants. That’s because I want to support biodiversity by providing native insects with what they need: pollen, nectar, and leaves for their larvae to chew, all from the native plants they coevolved with. At each stage of their development, most insects need food from the few plants they’ve evolved to focus on over the millennia. They’re usually not equipped to live off plants from other parts of the world.
The obvious exception to this rule is nectar. On any summer’s day, it’s easy to observe pollinators sipping nectar from nonnative flowers. That’s how butterfly bush (Buddleja spp.) got its 15 minutes of fame. Pollinators do benefit from nectar from a variety of flowers, not just natives.
Eastern tiger swallowtail sipping nectar from butterfly bush blooms
By May and early June, when lots is flowering in my yard, there was more of a balance. In addition to nonnative hellebores, daffodils, tulips, and vinca, there was native dwarf crested iris (Iris cristata), chokeberry (Aronia arbutifolia), wild geranium (Geranium maculatum), smooth Solomon’s seal (Polygonum biflorum), and Virginia bluebells (Mertensia virginica).
Native dwarf crested iris
On it went through the summer: native Catawba rhododendron (Rhododendron catawbiense), trumpet honeysuckle (Lonicera sempervirens), and mountain laurel (Kalmia latifolia) flowered in June. In July there was native tickseed (Coreopsis verticillata), Stokes’ aster (Stokesia laevis), and mountain mint (Pycnanthemum muticum). In August, native wild senna (Senna hebecarpa), goldenrod (Solidago spp.), phlox, and purple coneflower (Echinacea purpura).
Three kinds of native milkweed bloomed in succession, offering special food for caterpillars of monarch butterflies: swamp milkweed (Asclepias incarnata), common milkweed (A. syriaca), and butterfly weed (A. tuberosa). Monarchs need milkweed to reproduce, and I hope my collection helps them on their long migration.
This week I found tickseed and goldenrod blooming along with the first New England asters (Symphyotrichum novae-angliae).
It’s not only what I’ve planted. When the native white wood asters (Eurybia divaricata) that pop up everywhere in my yard as volunteers come into bloom later this month, they’ll be the dominant floral resource for weeks.
To increase the proportion of natives blooming to at least 50 percent, I’ll need to add more of some plants that are thriving already. A promising candidate is Phlox paniculata ‘Jeana,’ recommended as a butterfly magnet. As research on the best plants for pollinators expands, we’ll have more guidance on which native plants to choose. Drought is teaching hard lessons on which to avoid.