I don't know how to trade with NPC's

[Vekkizunt]

in the wiki it say's you can trade strange plants but i don't know how to, i have the orange one, but i can't get any of the special dyes

[Cyclone]

You need the Dye Trader NPC to show up.

[Alucard †]

Only Dye Trader can do that. Hit "Strange Plants" in his dialogue when having at least one strange plant in your inventory.

The plant will be "consumed" and you will get 3 of the randomly selected special dyes each time you do this.

[Vekkizunt]

thank you