I DMed some 1st edition AD&D today....
45 minutes ago
Hogweed: No. Appearing: d100, HD <1, AC 8; Atk 1 trample (0-1 hp + Special); Move 15; Save 18; CL/XP B/10
Giant Hogweed: No. Appearing: Up to 1 (% chance = number of hogweeds appearing), HD 5; AC 6; Atk 1 trample (2d6 + Special); Move 12; Save 12; CL/XP 5/240
Special: Both giant and normal sized hogweeds attack by attempting to trample their victims and transferring their contact poison. Smaller hogweeds are easily fled from, but giant hogweeds will pursue targets as far as a hundred yards from their smaller hogweed companions. Fire attacks against them are at +4 to hit and +1 damage but if they’re set ablaze, attackers within 20’ (60’ for giant hogweeds) must save vs. poison (gas) or suffer d6 damage per day until cured.
Poison: Contact causes d6 hp of damage per day in a victim if the body part(s) affected is exposed to natural light (roll to see what part of the body was hit - the oil also will penetrate clothing in one day if not washed). Cure disease will remove this affliction. Head or face contact may require a saving roll against blindness.