Hi, Ben!
It looks like the soil it's in got contaminated by 2,4D, a common weed killer, or maybe the plant got accidentally sprayed. I would transplant it into a water retentive potting soil, and spray it with compost tea, or commercially prepared humic acid. Since you will need to wash off all of the old soil, you should prune the top severely--reduce the foliage by half--and make the final rinse of the roots a dilute solution of seaweed extract. Keep it in the shade outside for a week after transplanting, so it can get over the shock, without losing too much of its sun adaptation.