Breeder
Royal Sluis
2 US plant patents, granted between 1992 and 1993.
On the name: these patents were filed under 2 spellings, counted together here — Royal Sluis (1), ROYAL SLUIS INC (1).
Already in the public domain — 2 cultivars
Most recently freed first. Anyone may propagate and sell these plants — though the name it is sold under may still be a live trademark.