Saving Flowers ?

[AlittleSalt]

My original thought for the titles was, "Letting the Weeds Grow" but saving some living flowers is what I want to do. I want to transplant them into a pot/s.

Now, I will explain. A few weeks ago I found the reason our garden is growing stunted is because there are Root Knot Nematodes RKN in the main garden. I spent a week or so getting the tomato plants out and solarizing about half the garden. The other part of the garden I let grow however it wanted as I recovered from all the work.

This week, I started pulling failing plants and couldn't help but notice all the weeds growing. I started weeding and found these flowers growing. I'm pretty sure it is purslane. I didn't plant it.

Should I transplant it into a pot of potting mix? I am completely new to planting in containers. I have potting mix already for next years tomato potting up stage. Would that work or should I buy something different? The pots I have will hold at least 3 gallons of mix.

Here's some pictures. If I'm wrong about what it is - please let me know.