Beth Kleinpeter
Finally, the gods have bestowed autumn upon us humidity- and sun-beaten Louisiana souls. It’s true that Halloween could be 45 degrees or 85 (and let's be real … so could Christmas)—and still, it seems that the heaviness of summer has finally faded. Time to lean into our natural world, stay outside, and bask in the seasons we cherish South Louisiana for.
This time of year brings to bloom flowers that not only gratify the eye but are of utmost ecological importance. Fall energy, these late blooming flowers, and the anticipation of coming winter bring to my mind the notion of “keystone” plants. The term “keystone” is borrowed from architectural parlance, referring to the tip top placement at the crown of an arch that holds the entire arch together. Without this cornerstone, structure quickly and visibly declines. This concept holds relevance with the living organisms of our natural world as well. Our native flora and fauna have evolved over millennia together, developing complex symbiotic relationships that are irreplaceable—formed long before we decided to start studying, categorizing, and controlling them. The monarch butterfly and its host Milkweed (Asclepias species) are a well-documented example of such an important flora and fauna relationship. Lesser known are the infinite other vital relationships native plants have with specific animals. “Keystone” species like milkweed are those that, through their relationships to fauna and related natural systems, play a large part in holding the entire ecosystem together.
Many of our native keystone species emerge in the fall, offering both late season food sources and habitat benefits to carry our wildlife through winter. These plants, such as goldenrods (Solidago species) and black willow (Salix nigra), can be aggressive, even weed-like. But if we can stay out of the way, these plants will do what they evolved to do: offer wildlife exactly what it needs to thrive with great abundance.
Here, I’ll share a handful of the keystone plants I wish I encountered in more residential and commercial spaces. Because these plants are so very crucial to wildlife, I encourage you to seek out spaces where they can be allowed to reseed, spread, and offer as much winter goodness as possible. Even better if you can resist cutting them back until spring. The spent seedheads of the flowers are a significant winter food source for wildlife, the dried hollow stems of many serve as overwintering homes, and the herbaceous materials are used to build new homes.
Goldenrod (Solidago, all species)
Goldenrods belong to the Asteraceae family, which happens to produce more keystone perennials than any other, including our aster and sunflower plant groups. The Asteraceae family is second only in benefit to the Fagaceae family, which boasts the most beneficial keystone species of all, our oak trees.
Most acquaintances of mine seem to know goldenrod, as it is perhaps our most prevalent of roadside wildflowers and the absolute queen of fall bloomers. We have more species of goldenrod in Louisiana than I can comprehend; I seem to learn a new one each fall. This plant does great in poor and disturbed soils, and most species seem to thrive just about anywhere. It is an aggressive perennial, so take heed when planting in small spaces, or choose spaces you don’t mind it taking over. I find both Wrinklelead Goldenroad (Solidago rugosa) and Bluestem Goldenrod (Solidago caesia) less aggressive options and relatively easy to access. The latter grows in semi-shaded woodland spaces and is a precious addition to any shade garden. And finally, fear not…contrary to popular belief, goldenrod is not what causes your fall allergy attacks. Our goldenrods bloom simultaneously with ragweeds, which are pollinated via wind and add tremendous quantities of pollen to the air, which we then breathe in. By contrast, goldenrod is purely insect-pollinated. Though the plants differ significantly in appearance, the goldenrod flower, with its bold yellows, is more visible to our eye, leaving the ragweed unnoticed and escaping blame.
Black Cherry, Prunus serotina
The black cherry is my current tree fixation. The Prunus family supports over four hundred species of butterflies and moths, making it also a top tier keystone plant family. Black cherry is so common that odds are you may have one popping up in your yard, especially if you have any natural woods nearby. I believe the tree to be completely under-utilized with intention; I see it most often only in a space because it volunteered itself there. The tree has a whimsical, lanky yet narrow form. The cherry bark is precious, and the seedy deep red cherries are my favorite native spring fruit with limitless culinary possibilities. An easy favorite is the Louisiana cherry “bounce”—prepared in various ways but largely using wild cherries infused with bourbon and spices.
Sweet Joe Pye Weed, Eutrochium purpureum + Hollow Joe Pye Weed, Eutrochium fistulosum
Another all star from the Asteraceae family, pye weed is especially beneficial as a late summer bloomer, emerging after many spring blooms have faded and fall’s have yet to come. Both species are found throughout our region. The Sweet Joe calls wet shaded woodlands its home, whereas the Hollow Joe, with its vanilla-scented flowers, prefers sunny meadows. Both grow tall with sweet mauve flowers in large flower heads. I pass large ditch stands of Sweet Joe often on my drives through rural St. Tammany Parish.
Little Bluestem, Schizachyrium scoparium
I would consider Little Bluestem to be the most prevalent native grass in our neck of the southeast. With that in mind, you could imagine how easily this one can spread across a space. With attractive, wispy blue/silver blades and a bounty of ecological benefit, the grass should be used more often in landscaping. As long as you avoid large reseeding, the grass can be a great way to add texture and color interest to a designed space. I plant it often alongside purple coneflower (Echinacea purpurea), gaura (Gaura lindheimeri) and giant coneflower (Rudbeckia maxima) for one of my favorite wildflower combinations. Even better: find a space (perhaps a patch of old lawn) to reseed en masse, then enjoy the soothing image of thousands of silvery blue blades swaying in a fall breeze.
Read more entries of Jess Cole's column, “Our Sustainable Garden,” here.
