The Milkweed Experiment is a success: I noticed something had been eating the leaves and took a closer look. Caterpillar poop!
By this spring, the milkweed had spread, sending up eight or nine shoots! I had to stake them (they're planted right at the corner of a raised bed where the neighbor's downspout overflows constantly, and in heavy rain anything growing there can get shredded) but they thrived, blooming heavily and sending out a half-dozen warty outer-spacey seed pods:
1 week ago