The best way to grow Californian poppies is to sow them directly into the ground in spring or autumn, as they don't like having their roots disturbed. They prefer light, well-drained soil but will thrive almost anywhere, as long as there is sun and the ground isn't waterlogged.

Determined to find out which poppies combined the best colour, quality and length of display, the Gardening Which? team tested 32 varieties at their trial gardens at Capel Manor College, north London. After raking the soil to a fine tilth, they sowed around 100 seeds of each variety into two-metre square plots. Next the soil was gently raked to cover the seeds, and the emerging seedlings were thinned to at least 15cm apart. The plants bulked up quickly, with most reaching a height and spread of 50cm, and by the start of June were starting to flower. Gardening Which? found that making four successional sowings at two-week intervals, lengthened the display by a couple of weeks.

Read on to find out which were best...

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Please note, although all of the products have been tested, Which? has not tested the quality of service from the suppliers mentioned below.