Dutchman’s breeches flowers very early in the spring typically at the end of April but this year closer to mid-May. The bright white 'pants' look like they are hanging on a clothes line to dry.
Small plants take a few years to establish and flower but it’s worth the wait; plant in small masses for better effect in a woodland garden. The foliage yellows and dies back by mid-June so it's a good idea to inter-plant with later flowering woodland species such as false solomon’s seal to cover the void left after dormancy.
The timing of flowering of dutchman’s breeches corresponds with the emergence of overwintering queen bumble bees. As queen bumble bees emerge from hibernation, they fly low to the ground in woodlands searching for appropriate nesting sites in abandoned rodent holes, leaf piles or other dry locations. The low growing, Dutchman’s breeches serves as an important nectar source to be used in the initial provisioning of their nests.
Once they have a good hold, they rotate their bodies in order to access the flower opening, directing their head toward one of the nectar spurs. Pushing their tongues then heads in between the outer and inner petals opens the flowers and allows them to reach the nectar in the spurs. Pollen is brushed onto their head and thorax, as the inner petals are deflected revealing the anthers. Their front legs often grasp the inner petals which helps expose the anthers and stigma and ultimately transfers pollen onto their forelegs.
Other smaller worker bumble bees chew small holes in the two nectar spurs to steal nectar because they are not strong enough to pry open the petals and have shorter tongues than queen bumble bees.
Like many other spring-flowering woodland plants, the seeds of Dutchman's breeches are dispersed by ants. Ants are attracted to the protein-rich, fleshy elaiosome attached to the seeds. They carry them back to their nests consuming the elaiosome and discarding the fertile seed in their nest's trash pile.
In the absence of queen bumble bees, the flowers of dutchman’s breeches are self-compatible and often self-pollinate.
Macior, L. W. (1970). The pollination ecology of Dicentra cucullaria. American Journal of Botany, 6-11. Retrieved from: http://www.jstor.org/stable/2440374
Macior, L. W. (1978). Pollination interactions in sympatric Dicentra species. American Journal of Botany, 57-62. Retrieved from: http://www.jstor.org/stable/2442554