Well, here's what happens, see. We have this field next to our driveway that gets mowed about once a month. The nettles get cut down, but then they grow back. What's out there right now isn't any more than abour 6" tall, if that. I don't know if that counts as "young" or not, but the current crop hasn't been growing any more than about 3 weeks.

I'll remember that about the top leaves. :-)