I have a small patch of pink turtlehead (Chelone obliqua, Zone 4), sometimes called twisted shell flower, a perennial that blooms in late summer through early fall. They send up 30-inch (75-cm) spikes of hooded pink-purple blooms, similar to the violet-blue helmet flowers of ‘Bressingham Spire’ monkshood (Aconitum carmichaelii, Zone 3). The monkshood begins blooming a little earlier, but then are concurrently in flower with the turtleheads through early fall, and they’re good plant partners. One year, I had the continued presence of three hummingbirds in my city garden, and the turtleheads were one of their favourite breakfast and dinner stops. The hummers were so eager to get at the turtlehead nectar that sometimes it looked as if the flowers had been electrified and were jiggling around like marionettes.
I was curious to know why the hummers were aggressively fighting each other for turtlehead nectar. My turtleheads make showy flowers and I presumed they had been hybridized, but, in fact, my clump of C. obliqua is a species, and produces superior nectar. The hooded flowers look a bit like a turtle’s mouth (well, sort of) and provide a receptacle to collect and preserve fresh nectar, providing the perfect access for the long beak and delicate tongue of a hummingbird.
There are some turtlehead cultivars, such as C. lyonii ‘Hot Lips’, which has shiny green leaves and rosy pink flowers. Another is C. glabra ‘Black Ace’, a tall, dark-leaved cultivar with 40-inch (1-m) stems and white flowers, hardy to Zone 6. Another species, C. glabra (syn. C. obliqua var. alba), has white flowers and is hardy to Zone 4.
Turtleheads can be found in the partial shade of woodlands, naturalized along streams and growing in organic soils with lots of moisture. They like consistent moisture, and will slowly spread by underground rhizomes when their water requirements are met. Mine are in typical garden soil that’s sometimes dry and, consequently, the clump doesn’t increase. (I suspect it would also have more flower spikes with regular irrigation.) Now that I know turtlehead produces the rich nectar my hummers prefer over the sugar water in the red hanging feeder, I’ll add more..
It’s interesting to see the clear preference hummers have for natural nectar over sugar water. Floral nectar consists of sugars (approximately 55 per cent sucrose, 24 per cent glucose, 21 per cent fructose), combined with trace components of minerals, proteins and amino acids that build in complexity. In scientific terms, nectar is the reward pollinators get for moving pollen from one plant to another. In bird terms, hummingbirds relish natural flower nectar as the best meal in the garden. This has shown me the wisdom of growing more species plants that will manufacture the enriched diet hummers prefer. The process of plant hybridization often retards nectar production, and I want to increase the stock of nectar-rich species plants I’m growing. I may have to pass up some pots of beautiful cultivars, but it’s a small price to pay for a summer of hummingbird antics.