Herbal Heritage. The cannabis dragon counts as a Plant in addition to its other creature types.

Amphibious. The dragon can breathe air and water.

Healing Aura. The dragon emits a passive aura that heals friendly creatures within 30 feet for 1d10 hit points at the start of each of its turns.

Grow and Bloom. The dragon can cause marijuana plants to grow rapidly within a 60-foot radius, creating difficult terrain and providing cover. The Cannabis Dragon gains advantage to stealth rolls while surrounded by marijuana plants.

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) piercing damage plus 7 (2d6) poison damage.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.

Smoke Breath (Recharge 5–6). The dragon exhales a cloud of hallucinogenic smoke in a 30-foot cone. Each creature in that area must make a DC 14 Constitution saving throw. On a failed save, the creature takes 21(6d6) poison damage on a failed save, or half as much damage on a successful one. Creatures that fail the save also roll on the Random Table Effects below. 

Random Table Effects: Roll a d10 for each creature that fails the saving throw to determine the additional effect:

1-2: The creature becomes extremely agreeable, unable to take hostile actions for 1 minute.

3-4: The creature hallucinates, seeing friendly creatures as enemies and vice versa for 1 minute.

5-6: The creature is overcome with a sense of euphoria, reducing its speed by half for 1 minute.

7-8: The creature becomes extremely tired, falling unconscious for 1 minute unless it takes damage.

9-10: The creature becomes extremely paranoid, causing it to take the Dodge action each turn for 1 minute.

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.

 Detect: The dragon makes a Wisdom (Perception) check.

Tail Attack: The dragon makes a tail attack.Melee Weapon Attack: +7 to hit, reach 15 ft. cone. Hit: 11 (2d6 + 4) bludgeoning damage.

Wing Attack (Costs 2 Actions): The dragon furiously beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 16 Dexterity saving throw or take 13(2d6 + 6)  bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.