Horseradish v's Dock leaves

[Dutchess]

Is it only the adult Horseradish that has leaves that taste hot then? I remember as a kid we had it in the front garden and on the way back from school I used to get my mates to taste a bit of the leaf stalk (or midrib) . Being used to the stuff the leaves tasted relatively mild to me (Dad used to pickle it - tears abounded when that stuff went through the old fashioned hand mincer, I can tell you!) but to the uninitiated that was hot hot hot! Wasn't I wicked *cackle*!

Always surprised me that the snails loved the stuff....

D.