Sow at a depth of approx.
0.25 inches (0.64 cm) and aim for a distance of at least
3.96 feet (1.22 metres) between Rose plants.
By our calculations, you should look at sowing Macgem about 35 days before your last frost date.
As Macgem is hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.