The columbine (Aquilegia canadensis) has begun to bloom around my home -the hummingbirds and I have been waiting. Columbine is an early flowering plant that Ruby-throated Hummingbirds (Archilochus colubris) visit for nectar as they migrate north each year. Flying from Central America, across the Gulf of Mexico, Ruby-throated Hummingbirds, usually arrive in the southern U.S. in mid-March, in the southern Midwest by the last couple weeks of April, and the upper Midwest and Northeast in the first couple weeks of May.
It’s widely thought that the hummingbird’s movement north is timed with the blooming of columbine (along with about 20 other early blooming species). And columbines do have many traits of “hummingbird flowers.” They are red, with long spurs. The nectar is kept at the very tip of the spur, making sure that a little hummingbird will bang his head on the dangling pollen. And the nectar of red columbines have twice the sugar content of all other columbines native to North America, which also makes it a good match for hummingbirds.
Phenology Forever
With plants and their pollinators, a very important part of their relationship is timing. And so, timing has its own field of study: Phenology. Phenology is the study of the timing of natural phenomena. It’s the nice kind of science where you sit on your front porch and watch things come and go. When does the redbud first bloom? When does it leaf out? When do the insects emerge? When does the columbine bloom? When do the hummingbirds arrive? These are all the seasonal biological events that Phenologicians (I just made that word up, don’t use it in public) pay attention to and record.
Now according to my terrible phenological records, the first Ruby-throated Hummingbird arrived in my yard on May 3rd and the columbine began blooming around May 9th. Someone was early, or someone was late. I don’t know who. Lucky for the hummingbird, on May 3rd the blueberry bushes were blooming and they thought those were ok.
Hummingbird patterns have been changing since the 1970s due to global climate change and winter and spring warming -things are getting a little mixed up. A recent study showed that compared to the last century, Ruby-throated Hummingbird’s are arriving in their eastern breeding grounds 11-18 days earlier than they did historically. The concern here is that, as these effects increase with warming temperatures, hummingbirds may ultimately become out of sync with their food sources. And from the plant’s point of view, columbine could become out of sync with one of its pollinators.
The Other Pollinators
The most effective pollinators of columbine in the Midwest are thought to be Ruby-throated Hummingbirds and four bumblebee species: the Two-spotted Bumblebee (Bombus bimaculatus), the Yellow Bumblebee (B. fervidus), the American Bumblebee (B. pennsylvanicus), and the Rusty-patched Bumblebee (B. affinis). There are perhaps others, but these were the ones recorded the last time the issue was thoroughly looked into, in 1966. Unfortunately, since 1966 millions of acres of habitat have been lost, agriculture has intensified in land use and chemical use, new diseases have arrived, and the climate has changed (all bad news!). Due to these factors, the Yellow Bumblebee, the American Bumblebee, and the Rusty-patched Bumblebee are all in decline. The Rusty patched bumblebee actually has the sad distinction of being the first bee to be listed as an endangered species in 2017. It’s population has declined 87% in the last 20 years, and it’s thought to be present in only .1% of its historic range.
So it seems columbine’s situation with pollinators may be more tenuous than I realized when I started this post. Hmm. Columbine is very capable of pollinating itself, and can actually achieve full seed set with no pollinators. But without pollinators, columbines are not able to cross-pollinate and bring in new genetic material. And, as those of us who married our cousins know (I accidentally married my thirteenth cousin!), this leads to inbreeding, less healthy plants, and over time increases the potential for extinction. I’m not saying that columbine is on the brink of extinction, but with three out of four of its bumblebee pollinators in decline, columbine genetics are likely feeling the effects.
So what to do? I don’t think resigning ourselves to increasingly inbred columbine is the answer. Well then, what is? What can we do? Well, I think the answer is… plant a pollinator garden. Ha. I know! That’s what I always think the answer is! But it is. If many of us gardeners increase food, nesting habitat, and chemical free spaces for bumblebees, and we convince our friends and families to do the same, bumblebee populations will increase. And that will be a good thing for columbine and so many other wild plants.
A Garden Note
Wild columbine is a great plant that’s really flexible in terms of moisture and sun requirements. It can go almost anywhere in your garden and do well. The foliage is delicate looking and can make a great weed supressing groundcover (since it’s an early leafing plant that beats the weeds), especially when planted in groups. In terms of visual appeal, it packs more of a punch in larger groups (7 plus plants), but can be delicate and airy planted out in smaller numbers. It’s a great addition to any garden.
And one final note for gardeners with a little extra space. In the studies I read, which felt numerous (although forgetting studies and accidentally re-reading them probably contributed to that), they would talk of small versus large populations of columbine. The contrast being that a small population would attract fewer pollinators and exhibit less cross pollination. In what I read, a small population of columbine was considered something like 30 plants, a large population greater than 90. Putting this in a gardening context, well, how many of us even have a small population of columbine? I have 4 mature columbine plants in front and four on the side of the house, two in the backyard. This quantity and distribution of columbine might be categorized as random and tiny. In the 7 years that the tiny patch of columbine has been in front, I recall seeing one hummingbird visit about five years ago. So I am going to try a new tact and create a middling population of columbine, and hopefully draw in more hummingbirds and bumblebees. I’ve put in about 50 columbine (they are easy to start from seed) split in three groups in the front yard. I’ve started to think columbine looks better in masses than in random, tiny spots, so in many ways, this will be a good change for the garden.
Do you get many hummingbirds at your columbine? Let me know!
Resources:
Pollination Ecology of Vernal Angiosperms. Macior, L. (1978). Oikos,30(3), 452-460.
FORAGING BEHAVIOR OF BOMBUS (HYMENOPTERA: APIDAE) IN RELATION TO AQUILEGIA POLLINATION. Macior, L.W. (1966), American Journal of Botany, 53: 302-309.
Effect of population size on the mating system in a self-compatible, autogamous plant, Aquilegia canadensis (Ranunculaceae). Routley, M., Mavraganis, K. & Eckert, C. Heredity 82, 518–528 (1999).
Pollinator–Plant Synchrony Tested by Climate Change. Willmer, Pat. Current Biology 22(4) (2012).
Assessing Migration of Ruby-Throated Hummingbirds (Archilochus colubris) at Broad Spatial and Temporal Scales. Courter, J., Johnson, r., Bridges, W., Hubbard, K. The Auk, 130(1) : 107-117 Published By: American Ornithological Society
Floral Anthocyanins of Aquilegia and Their Relationship to Distribution and Pollination Biology of the Species. Taylor, R. (1984). Bulletin of the Torrey Botanical Club,111(4), 462-468. doi:10.2307/2995896
Fact Sheet Rusty Patched Bumble Bee (Bombus affinis), Fish and Wildlife Service Midwest Region
Ruby-throated Humminbird, US Fish and Wildlife Service, by Kim Winter, Coevolution Institute
Common Columbine Pests: Columbine Leafminer and Columbine Sawfly, Wisconsin Master Gardener Program
Columbine, Illinois Wildflowers
Wild Columbine (Aquilegia canadensis), Adirondacks Forever Wild
Aquilegia Express: Red Columbines, U.S. Forest Service
A Wild Garden 