It’s National Wildflower Week—and from a restoration ecology perspective, it’s important to realize that wildflowers aren’t the same everywhere. If you decide to plant wildflowers in your yard, try to stay away from wildflower seed mixes, as these can contain varieties that aren’t native to your area (and may even be considered invasive!)
Instead, plant native wildflowers, which are adapted to the climate in your region, and which have co-evolved with native pollinators. The co-evolution aspect is important—especially for insect pollinators*, whose tongue lengths may be specifically adapted for particular types of flowers. A bee with a short tongue, for instance, can’t acquire what it needs from a flower with a longer corolla, such as Columbine (the state flower of Colorado).
It’s tempting to think then that a long tongue is better—or that just planting flowers with shorter corollas (yarrow, for instance) is better. But, long tongues are difficult to get into shorter flowers.
And that’s not all. Some pollinators like a “platform” to land on, while others will hover or burrow into the flower. Some pollinators are more likely to be out midday, while others are crepuscular or even nocturnal. A variety of native wildflower species will help create preferred forage for a variety of pollinators—and will likely create a bloom pattern that lasts over several months, rather than peaking at one particular point and then leaving pollinators without additional sources of food.
In some cases, planting a non-native species of a plant (like milkweed, Asclepias spp.) can actually be detrimental. Milkweed is the exclusive host plant for monarch (Danaus plexippus) caterpillars – but depending on the type you plant, it may not die back enough to kill off the protozoan parasite Ophryocystis elektroschirrha (OE). OE, when ingested by monarch caterpillars, causes the adult butterfly to be much weaker than their healthy counterparts—and carry spores to spread to other milkweed plants.
This can result in a decline of monarchs.
Fortunately, there are many native species of milkweed you can plant, which are adapted for your region—though getting your hands on seeds for these varieties may be a little more difficult.
If you’re not especially familiar with the native plants in your area—or have suddenly realized that your “wildflower mix” came from a company in the northeast and you live in Central California—there are a variety of resources that can help you focus your wildflower efforts to your region.
Many states have Native Plant Societies as well as university extension offices (like this one for Colorado and this one for Minnesota) that can help guide you toward an appropriate wildflower mix. The Xerces Society also provides lists of plant species by region. These easy-to-read lists note the bloom period (early, mid-late, etc.), common name, scientific name, flower color, maximum height, water needs, and additional notes that include what it attracts, shade tolerance, etc.
The National Wildlife Foundation has a Native Plant Finder (in beta) that allows you to search native plants by zip code and also spits out which butterfly and moth pollinators use particular plants as a host plant.
If you’re working on a restoration project, and are considering how to better include native pollinator habitat as part of your design, please contact us. Great Ecology has developed pollinator-focused plant palettes and landscape designs for a variety of projects, including one for a BASF site in New Jersey.
*There is also evidence that this makes a difference for other pollinators, including bats.