Val Bourne has been looking for the early signs of spring

I'm heartened by the fact that we are already over halfway between the winter solstice and the spring equinox. The days are getting longer and there's a touch of warmth in the sun to bring out those three heralds of spring - the crocus, snowdrop and winter aconite. Only yesterday I passed a steeply sloping cottage garden displaying hundreds of pure-white snowdrops. They were show stoppers on that frosty winter's morning and they have probably been there for a hundred years or more.

The snowdrop in the picture is a selected form of Galanthus elwesii named Comet'. The flowers have slightly green tips to the outer petals. Galanthus elwesii is very variable and this extremely large-flowered form was selected in the 1980s, from a colony growing on the Rock Bank at RHS Wisley. All snowdrops with G. elwesii blood have paler grey-green leaves, indicating a need for a sunnier position, and they usually produce large upright flowers with bold green markings early in the season.

White flowers show up well in late winter and early spring when light levels are still low. A mixture of white wood anemones (Anemone nemorosa), white epimedium (E. x youngianum Niveum'), the pretty white dicentra ( D. formosa Alba'), Viola cornuta Alba' and white pulmonarias woven among green leaves gives a woodland area spring sparkle. However as light levels rise, white flowers can be more difficult to place as they glare and bounce back at you.

By April the sight of pure-white pierces my soul. I can only shudder when I see Exochorda x macrantha The Bride' masquerading as a blackthorn lookalike on a bittersweet spring day, as threateningly as one of Hitchcock's platinum blondes.

If this were not enough, white flowers contain less colour pigment which allows for more air gaps in the petals. Therefore they brown as they die, a very unattractive feature.

For both reasons, any white plants flowering after May in my garden have to be softened with green or pink to kill the whiteout effect. The rose Madame Hardy' has a green button eye. Verbascum chaixii Album' has a raspberry-pink centre to every flower. And Hydrangea arborescens Annabelle' has green-veined flowers. Either that, or they have to be pale, warm colours like soft apricots or blush pinks. These both fade to cream and the Hybrid musk rose Penelope' is a late-summer star with a colour as flattering as wedding-day pearls.

Christopher Brickell (former Director General of the Royal Horticultural Society) will give an illustrated talk, "Snowdrops in the Wild" at Kidlington on Saturday, February 16, at 2.30 pm. The venue is the Exeter Hall, Oxford Road, Kidlington. Tickets may be obtained from Jim Rodda, 22 Reddings Drive, Amersham, Bucks HP6 5PX, or you can buy them at the door. Tel 01494 783254 for further details.

A new Snowdrop Garden at Ramsden House (off B4022 midway Charlbury/Witney and next to church) is opening for NGS on February 24 from 2-5pm. Admission £3, children free. You can see waves of snowdrops, originally planted in 1862, in this two-acre Victorian garden. Snowdrops for sale and home-made teas.