Fantastical Flora

The wither rose is the only flower that spreads a potion effect on the player, plus it is difficult to obtain. That design would bring a fantastical element to unfrequented parts of the world and promote exploration. 

• Ender Lilies/Lotus are floating or sprouting flowers in end dimension that give levitation effect for 2 seconds when passing by them. Could save players from falling in void. (Float near bottom of void or by slaying shulkers w/lightning bolt)
• The sniffer plants could have their own effects: (Torchflower= shrinking effect) (Pitcher pod=growing effect) or vice-versa from April fools update. A flower that grants regeneration could be added as a rare ancient seed you have to find in a distant biome, all of which cannot be bonemealed, must be pulled by sniffer.
• Poison vines/ivy (grow in jungle, or on pillager structures)
• Suspicious mushrooms: Grey cap w/orange spots, make you blind or night vision when walking on them in mooshroom islands. (Naturally grow In Mooshroom islands or by feeding mooshroom cows nether shrooms)
• In deep dark, there can be bone-white/blue skulk flowers that give player nausea and/or inverted controls when making sound near it,  like a lush cave flower but it spews blue spores around. (Naturally generate in deep dark, place lush cave flower beneath catalyst, or slay warden atop shrieker to obtain)