Friday, 11 March 2016

Wildflower of the Month: Sweet Violet

Sweet Violet
Image: Mike Porter
Sweet Violet is already in bloom in London, Home Counties, the West Country & Ireland and it's about to start flowering in the East Midlands. It's already in leaf in Scotland and should start blooming there in the next few weeks.

There are nine species of Violets in the UK and they are considered tricky to ID to species (that's why BSBI is bringing out a new Handbook about them later this year!). The Sweet Violet is, unsurprisingly, the only one with the distinctive violet scent. 

Sweet Violets have been used over centuries as edible flowers – crystallised violets, violet creams, even in posh salads! - and as a traditional herbal remedy for insomnia, headaches and depression. They were also used as a strewing herb - essential for those Elizabethans who famously had a bath once a year "whether they needed it or not"!

Heath Dog-violet
Image: Mike Porter
Fortunately, a simple sniff test, a quick look at the leaves and a check of the kind of habitat where you find your violet will help you to identify which one you are looking at.

The Dog-violets are all unscented:
Heath Dog-violet grows, helpfully, on heathy acid grassland and the leaf-base is not so heart-shaped as the other Dog-violets, while Marsh Violet likes it squelchy underfoot – if you are looking at one you are probably either wearing wellingtons or have wet feet! 

Common Dog-violet
Image: Mike Porter
Common Dog-violet is common and not so picky about where it grows and Early Dog-violet flowers a little earlier than the other Dog-violets on slightly richer soils than the Common Dog-violet. Separating these two can be tricky but some of the ID tips in the BSBI's Plant Crib for Violas should help. 

Both Sweet and Hairy Violet have hairs on the leaf-stalk (the others don't). You can usually see the hairs on Hairy Violet with the naked eye but you may need a handlens to see them on Sweet Violet. Or wait until it flowers and then sniff!

They both grow in woodland glades and hedgebanks, and Sweet Violet is often naturalised near churchyards and gardens, from which it often escapes into the wild. Hairy Violet also likes a slightly more alkaline soil than Sweet Violet.

Hairy Violet
Image: Mike Porter
Apparently there's a chemical in the scent of Sweet Violets which numbs the olfactory nerve, but our Violet expert Mike Porter (who is writing the new Viola Handbook) has heard about small-scale studies that say some people are unaffected and can smell Sweet Violets repeatedly. 

Fancy doing an experiment? Start sniffing Sweet Violets (once you’ve ID’d them correctly!) and let us know if you can still smell them after a few minutes. Great excuse for a wander in the woods this spring and you can call it scientific research! 

You can tweet your results to us at @BSBIbotany using the hashtag #WildfloweroftheMonth

I'm looking forward to talking about Violets in Scotland to Louise White on BBC Radio Scotland's #outfortheweekend programme later this afternoon. Don't worry if you can't tune in live, you'll be able to hear the broadcast later on iPlayer here. [LM: the interview is here, starts at 01:43:30]