Zinnia Giants of California

Huge fully double flowers, ten to twelve centimetres across, on sturdy stems at 90cm to a metre, in the full bold palette: scarlet, crimson, pink, orange, yellow, white and bicolours. An heirloom strain that has been in cottage cutting gardens for generations.

For cutting they are hard to beat. The stems are strong enough to hold a big head, the flower has real visual weight in an arrangement, and vase life runs ten days to a fortnight, which very few annuals of this size manage.

The one rule that matters is heat. Zinnias detest cold wet ground, and a plant put out too early turns yellow, sits still and often never recovers. Wait for genuine June warmth. Patience is the whole of zinnia growing; everything else about them is easy.

They flower from July to the first frost, and the flat open heads make a stable landing platform, so butterflies use them heavily on hot afternoons. Keep cutting and the plant keeps producing.