Bring joy to your garden throughout summer with gorgeous dahlias in your border, patio containers or stunning cut flowers in the home with our White Perfection Dahlia Spring Planting Bulb. Easy to care for, you can simply remove dead flower heads outdoors to keep the display going until the first frosts. Dahlia bulb size I. When to plant: March to June. Flowering time: July to October. Care guide: Plant dahlia tubers with the single stem facing upwards and the bundle of roots facing downwards. Keep plants well watered during growth and remove faded flowers. Once flowers appear use a high potash (potassium) feed to encourage flowers to grow.