All our plants are strictly kept emersed (not in water), so are free from pest snails. Unclean, badly maintained plant tanks are the main cause for pest snail infestations. As much as this is not a 100% guarantee, snails on plants is a very rare occurrence!
In-vitro plants (1-2-grow, Easy Grow etc.) are grown in laboratories and 100% guaranteed to be pest and algae free!
Worms and/or slugs on plants
Aquarium plants are grown in standard greenhouses (just like your garden plants). These are large industrial-scaled operations. So little hitchhikers can be found on potted aquarium plants on occasion. Especially since EU grown aquarium plants are usually not treated with pesticides.
Most of those can be easily removed with a quick rinse. If they should make their way into your tank, they typically end up as fish food, but they will never pose a risk for your livestock (fish, shrimp or snails)!