Visit to Black Earth Rettenmund Prairie recommended

Black Earth Rettenmund Prairie is one of southern Wisconsin's jewels, and I strongly recommend a visit in the next few days. Kathie and I manage this prairie for the Prairie Enthusiasts, and we make a special effort to monitor its phenology.

Right now, wood betony (Pedicularis canadensis) is in its full glory, and all prairie enthusiasts will enjoy seeing this fascinating plant. Rarely will you have the opportunity to see such great floristic displays (see photo above).

Wood betony is called a hemiparasite. This is because it is capable of parasitizing grasses (as well as some forbs) without actually killing them. Wood betony's roots are capable of penetrating the host plant and transferring nutrients. However, it remains a green plant, and is capable of photosynthesis.

If you look at a wood betony colony carefully, you will notice that it is surrounded by a plant-free zone, although not far away normal plant growth occurs. Black Earth Rettenmund Prairie has an unusual amount of wood betony, and one idea for why it is such a forbs-rich site is that the grasses are held in check by hemiparasitism. Such a species has been called a "keystone species", since even thought it is a small plant it has a large ecological effect.

There are places on Rettenmund where you can see this dynamics in action. Examine the grass density in a betony-rich zone and compare it with a betony-free zone nearby. The difference is striking. I saw one sharp line between a patch of needle grass (devoid of wood betony) and a patch of wood betony (devoid of needle grass). Interesting plant ecology!

There are lots of other things to see at Rettenmund right now. The shooting star displays are phenomenal, especially in the south unit (worth a 15 minute walk). Other plants in full bloom include hoary puccoon, bird's foot and prairie violet, seneca snakeroot, false toadflax, and rock cress. Within a few days, the north side should be full of flowering downy phlox. There is always something happening.

And the delight here is that this prairie is less than a 30 minute drive from the west side of Madison and no lengthy hiking is needed to see things. Within five minutes of getting out of your car, you will be in the midst of a carpet of wood betony. (But please stay on the marked trail.)