Roi de Roses is generally regarded as a tender plant, so remember to wait until your soil is warm and the night time temperature is well above freezing before moving outside.
Growing Roi de Roses from seed
By our calculations, you should look at sowing Roi de Roses about 91 days before your last frost date.
Transplanting Roi de Roses
Roi de Roses is tender, so ensure you wait until all danger of frost has passed in your area before considering planting outside.