Sempervivum Seeds - Hardy Mixture2nd Year Maturity. Hardy Mix sempervivum seeds grow exotic and eye catching succulents ideal for many dry and thirsty gardens across North America. Hardy Mix seeds grow creeping 4 6 tall purple and mahogany ground cover perfect for accenting walkways, fences, patios, or lining a flower bed. Hardy Mix sempervivum seeds promise hardy, compact, and drought tolerant succulents bursting with dazzling pink, cream, yellow, and red rosettes. Hardy Mix is easy