Echeveria Mexican Snowball, Echeveria Elegans "Mexican Snowball", is not cold-hardy. You should plant it in a container you can bring inside. The wrong pot can cause your plants to become waterlogged and even hinder their growth. Century Plants: What You Must Know (2:50). Big Blue is no longer the star. The plants are still very delicate and cannot tolerate the full sun. They will burn if they are exposed to direct sunlight. Shade is vital for all gardens. It can take between three and five years for even fast-growing trees, like Acacia longuefolia, to provide it.