- You Will Get 500 Seeds Of Red Scarlet Flax Linum Grandiflorum Rubrum Flower Seeds. - Description: - Name: Scarlet Flax. - Scientific Name: Linum Grandiflorum Rubrum. - Color: Scarlet Red. - Plant Seeds: Outdoors After Frost / Indoors Weeks Before Last Frost. - Plant Height: 18 - 24". - Plant Spacing: 6 - 9". - Bloom Time: Apr – Sept. - Hardiness Zone: N/A. - Light Requirements: Sun. - Soil & Water Preferences: Average – Dry.