We all want to protect pollinators and it seems that the best way to do that is to have a lot of flowers so they can feed on them. But if you’ve ever checked a seed catalog or visited a plant nursery, you may be overwhelmed by all the options. How do you choose what to plant? In today’s post we will chat a bit about the why’s of these choices and we’ll share some resources that may be useful next time you’re trying to make those decisions.
Each pollinator species is unique
As all species in the world, each pollinator species has unique reproductive, nutritional, and habitat requirements to survive. For example, a bee that nests in the early spring needs food and habitat that will be different from those of another bee that nests in the summer, or of a butterfly that emerges from its metamorphosis in late spring. For an early-spring bee it will be key that flowers are available early in the season. Those will be of no help to a summer bee. Likewise, a late spring butterfly will be able to enjoy the nectar from flowers that were not available to the early-spring bee.
Along with the timing of emergence, each pollinator is unique in its anatomy and sensorial abilities. For example, long-tongued bees can reach the nectar of flowers that may be too deep for short-tongued bees. Similarly, because of their extremely long mouth parts, hummingbirds and butterflies usually can access very tubular flowers that are just out of reach for other pollinators.
It’s not only the shape of the mouth parts of the pollinators that will play a role in what flowers they can feed on. Their general body shape and physical abilities will also define this. For instance, butterflies can’t regulate their flight as well as hoverflies or bees do, and because of this, when they visit flowers they need to have large surfaces on which to land, while bees and hoverflies may not really need them.
Finally, different pollinators have different sensorial abilities, with some being able to see some parts of the light spectrum that others may not. On this, butterflies and hummingbirds can see many different colors including UV light, bats that pollinate are blind, and bees have a broad spectrum of light vision but can’t differentiate many of the colors we can.
So now you may be asking yourself why I am talking about all of this. How does this relate to the topic of this post: how to help pollinators with flowers? Bear with me, I’m getting there!
How should I choose what to plant to help pollinators?
As you may be guessing by now, because each pollinator has slightly different life requirements, if you want to help as many pollinators as possible, your best shot is trying to diversify your garden or flower bed. I like to think of this as if I were holding a dinner party at my house and I want to have as many of my friends enjoy the food.
If I know that some of my friends are vegan, lactose intolerant, or allergic to nuts, I will make sure that they find something to eat at my table. If I don’t have anything for them, they will be hungry and sad, and they will also probably decline any future dinner invitations from me (how sad is that!?). So, I like to think about these pollinator plantings as a party I am hosting for a whole season, and where I will make sure that all my little friends always have something to eat so they come back next time I invite them over!
The key to attract the most pollinators is diversifying our gardens! Ideally, the choice of plants should include different flower colors, shapes, and sizes available throughout the season. This means that there will be always several different types of flowers blooming at the same time, even though no one plant may be flowering throughout the season. Along with this, if one is trying to attract specific pollinators that have very specific food requirements (for example, oil-bees, monarchs), one would also have to make sure that the pollinators’ required food is also present (take a look at this recent post to learn more: Why do pollinators visit flowers?)
Another aspect to consider when deciding what to plant is the fact that native pollinators usually get appropriate nutrition at the right time of their life cycle if they feed on plant species that are also native to the area. For this reason, if one wants to help pollinators, native plant species are usually recommended, and in particular, avoiding invasive exotic species is key. In fact, invasive species, in addition to not providing ideal food for native pollinators may also displace native plant species, reducing even more the diversity of your flower bed and the pollinators who will visit it. Finally, this also means that a “good” flower mix for pollinators from Europe is probably not going to be ideal for Maryland pollinators.
But then, what should I do?
There are so many things to think about! This is truly a brain twister, right? Luckily for you (and me) many biologists, ecologists, and conservation specialists have been thinking about this for a while. Today, floral mixes have been created that are appropriate to different regions of the United States. In the state of Maryland, the Department of Natural Resources has created a neat list of species you can plant depending on the conditions on your land. The Xerces Society has also put together a list for plants appropriate for different states. Alternatively, if you would like to just favor specific pollinators, you can target their preferred plants. For finding seeds and starts for these plants, take a look at this great resource the Maryland Native Plant Society has put together!
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.