Crocus in focus

These cheerful flowers are always a treat, with species that bloom in autumn, winter and spring. Val Bourne picks the plants to go for

Crocuses really are harbingers of spring and cheer up any garden early in the year. They’re also vital for early-flying bees because a rise in daytime temperature of just 0.5C (1F) prompts this flower to open wide. The goblet shape traps warm air, allowing nectar to flow, and as the temperature falls again the flower closes. The long floral tube, buried below ground, means that many crocus species can set seed despite flowering in cool conditions. There are 80-100 species, mostly found in bright, open positions in the Alps, southern Europe and near the Mediterranean. When planting in autumn, give corms a bright spot so flowers are encouraged to open. All crocus corms are attractive to mice and voles so plant them a little deeper or cover with squares of wire mesh. Smaller corms usually flower in January or February. More subtle in colour, these smaller-flowered crocuses often have feathered patterns on the outer petals designed to lure in pollinators. They’re lovely, but most aren’t strong enough to push through turf, and need topping up every third or fourth year. Grow in warm, well-drained positions on a sunny edge, or round a deciduous tree. Dutch crocus have corms about an inch across, and come in clearer colours, usually without intricate feathering, although some, such as purple and white ‘Pickwick’, do have stripes. They flower in March or April and can push through grass. They’re also longer lived than smallercormed crocuses, forming generous clumps when happy. A Russian-collected crocus, purple and silver-grey ‘Vanguard’, obligingly flowers two weeks earlier. Plant them en masse through grass, but do wait for the foliage to die down before you mow. It’s thought that Flemish herbalist Ogier Busbecq brought back the first spring-flowering crocuses from Constantinople in the 1560s. Corms were then sent to botanist Carolus Clusius at the Botanical Garden in Leiden in the Netherlands. By 1620 the Dutch were breeding and selecting in earnest and soon crocuses were painted by Dutch artists. The key colours, white, purple and yellow, chime with spring. One early crocus from Crete, Crocus sieberi ‘Tricolor’, captures all three colours. ‘Blue Pearl’ is almost as early, but I find its foliage lasts too long. Soft yellow ‘Cream Beauty’ has a prominent orange stigma and style. For large flowers opt for stripy ‘Pickwick’ or all-purple ‘Grand Maître’, which produces up to three flowers per corm. ‘Remembrance’ has deep-purple flowers with a silver sheen. Crocus tommasinianus is a species found in light woodland, normally on rocky slopes. It spreads by seed in grass under trees, especially on lighter ground. ‘Whitewell Purple’ is an excellent named form, but seedlings vary, which gives a spangled, natural look that some gardeners find weedy. The delightful ‘Yalta’, a newer hybrid with ‘tommie’ blood, has alternate purple and grey petals and a huge orange style, almost like a feather duster. I love it!

The goblet shape traps warm air, allowing nectar to flow