Easy May Flower Seeds for a Garden Full of Color Perfect for sowing in May across: US Zones 310 UK after last frost, from late April to early June Australia temperate & subtropical areas May = autumn sowing – Sunflower direct sow, full sun – Celosia sow in warm soil or start indoors – Bachelor Button best for cooler spring temps – Coneflower Echinacea direct sow or transplant – Zinnia direct sow once soil is warm – Tickseed Coreopsis easy to scatter, drought-tolerant – Yarrow hardy, thrives in poor soil – Black-eyed Susan direct sow, loves the heat – Nasturtium edible and beautiful, loves poor soil Direct sow after frost ends. Works in US, UK & Australia adjust timing for your climate.