Carex Seeds - Bronco63 70 days. Bronco carex seeds grow lightly golden and bronzed ornamental grasses in an arching foliage maturing at about 12" tall and 14" wide. Carex grass performs well in full sun and heavily wet conditions. Bronco carex grass is a smaller variety and a perfect fit for planters, baskets, and rock gardens. Carex grass seed is available in small quantity to bulk at wholesale pricing. 100 seeds. Growing Bronco Carex Grass Garden Seeds Taxonomy: Carex