The wheels. There are lots of things growing here, from left, lemon balm, bee balm, the pot with the woodbine and pineapple coleus, more bee balm, and Golden Alexander.Close-up of the new pot (a gift) with coleus and woodbine in it. (This would be formatted a lot better, if I knew more about how blogger works.)
UPDATE! It's common scurvy-grass, cochlearia officinalis! Thanks to ValRay Town for the ID!
They say the flowers are good in salads if you remove the main stem. It's said a tea of the root can be used as a fever reducer. It ALSO says it likes moist woods, which answers my question on why it's not really big after 6 years. I have full sun, little shade, and it has done well each year, but not enough to divide or harvest. Learn something new every day!