>>1329100They are just like peppers and tomatoes or any nightshade plant. They do exceptionally well spread by seed.
>>1329120There are many species of physalis, not just many cultivars. Some are sweet, some sour, and some meh. As with all nightshade plants, they have solanine in them. Some have more than others. Green unripe fruit will have more than fully ripe fruit. You need to google up specific species info to find out how edible they are.
The first symptom of solanine poisoning is a real, "green," feeling of being sick/nauseous and/or gastrointestinal pains.
My purple tomatillos come up like weeds every year, from any location the fruit dropped.