Low oxalate perennial greens?

I would really like to find some perennial greens I can use in large quantities. This means they shouldn't have an overwhelmingly strong flavor, they should be low in oxalates, and they should grow large quantities of leaves.

Does anyone know of such a plant? I live in Central Texas (hot summer zone 8b), and have heavy clay soil that I have modified in places.

I should add that I hope to be pregnant soon, so edible hibiscus is out, as is anything in the same family unless proven safe for pregnancy. Unfortunately, I think this rules out everything from turk's cap to musk mallow.

This thread asks a similar question.

C West said, "I will only eat oxalate containing greens (good king henry, sorrel, caucasian spinach, chickories) once a week, the rest of the week eating brassicas.

Jordan said, " From what i can tell the Oxalate can be significantly reduced by cooking either by boiling or steaming. We often employ a steam and fry in butter

https://permies.com/t/132287/perennial-vegetables/Oxalate-Questions

I don't know what you consider strong tasting, but I think kale is pretty mild, especially the variety I have. It's Homesteader's kaleidoscopic perennial kale grex from experimental farm network. It would easily be perennial in your climate. It does fine in hot summers, at least for a few weeks at a time. Last year we had high 30s, up to 45C for over a month. I didn't water it at all and it was fine, although not as happy as I've seen it at other times.

Also from EFN is Dietrich's wild broccoli raab. Its a feral turnip, so low oxalate. When the weather is cool, the leaves are mild and sweet. They get a bit spicy after the seed pods start forming, but I just switch to kale at that point. The broccoli raab is a self seeding biennial, not at all picky about where it grows.

These two plants have become my green staples, and I'm very happy with them. I'm even getting ready to collect what looks like a ridiculous amount of seed from a 4x8' patch of the raab. I plan to use it for sprouting over the winter while everything's under snow.

Thanks for the info, Anne Miller.

And that's a good idea, Jan White. I will probably buy some of those kale seeds.

I might give watercress a shot, but nasturtiums (closely related) have been quite stunted both years I've tried to grow them. Not sure what's up. Also, perennial arugula. I haven't tasted either of those, so I don't know if I can sub either one for spinach in recipes, which I'd like to be able to do with some perennial or other.