Look to ensure a distance
11.7 inches (30.0 cm) between Serena Sunburst seeds when sowing to make sure your seedlings have enough space.
By our calculations, you should look at sowing Serena Sunburst about 42 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Serena Sunburst is a hardy plant.