Evolution at work

Once a week, I spend two or three hours pulling weeds in my flower beds—it’s hard work achieving that casual cottage garden look. One of the more pervasive weeds I’m always pulling up is oxalis—sourgrass, false shamrock, whatever you want to call it. It grows in two colors: bright green and a rusty red. Four years ago when we bought the house, most of what I was pulling up was bright green, but now I’m pulling up mostly rusty red oxalis. And I just realized today that I now have mostly rust red oxalis because it’s the same color as my mulch, which means I miss it and it gets to reseed itself.