I have a packet of sorrel seed from Real Seeds and I'm about to sow some, however since it is perennial I was wondering how many I should sow? I have no idea how vigorous it is nor whether it is invasive. I have noted that it has deep roots and have earmarked that for potential future pain in the neck! We are a household of four and sometimes five adults. They eat what I make (poor souls)! ;)
It's not invasive and makes small(ish) clumps which only expand very slowly. In the winter it dies down completely and the leaves slowly emerge in spring. You only need a few plants because it's too astringent to consider using as a vegetable in its own right; but it works well in a creamy sauce, or omelette filling.
And it seems happy in semi-shade. Ours sits under an old apple tree.
Thanks Trevor! I'll sow about 6 seeds and say what comes of them.