This plant grows in rough patches in the sand dirt between my stone wall and the grass on the edge of my hill. It's in a shady spot and seems to have a purple scraggly skirt and then a tall green shoot. It's spiky like thistles or something, maybe a lousewort? Very cool purple though.

What part of the world is this plant in? It may be thistle (Cirsium horridulum) - it often has purplish basal leaves. You'll know when it flowers.

Hi & welcome! Are you able to add a pic of the tips of the green stalks?

I think CT, if the 5 digits are ZIP code. Link to ZIP 06231 in the gardening zone tool on this site:
https://garden.org/nga/zipzone...

It LOOKS like a thistle, but does anyone know of a thistle with a purple skirt of leaves below it like this? I realize now it's not the best picture because I cut off the top, but you can see the tops of smaller ones around it in the background and there's nothing special about them. It's just a spiky stalk, the purple skirt would almost certainly be its identifying feature. Maybe some kind of fern?

And yes, the zip is in Connecticut, USA.

I would say not fern , my thought is more along a groundsel , it looks like a thistle
or one of the other spring weeds that flower yellow: yellow cress , wild mustard,

the purple color of the lower leaves (rosette) are from the first years growth , so you are looking for a bi-annual.

* biennial