Do you have photos of items you've made in the past besides the one in your shop currently? A website used as a portfolio would be a great way for people to see your creations. Do you have more photos of them being worn? Or being made? Get a picture in your avatar as well. That will entice people to have a look.
Even your other jewellery items can be an entrance into your shop, so don't avoid posting and listing those, as people might see them and follow them into your shop, then accessing your new flower jewellery!
As for promoting the item in your shop, see if you can post it on some websites- art websites, etsy teams, wanelo, facebook, twitter, tumblr, stumbleupon, pinterest. Try websites that address weddings, and try
Could you get some business cards made up using the images of your jewellery?
As someone that has been to a lot of garden shows and fairs, perhaps look into exhibiting at one of them locally. In the UK, they often have a lot of flower related things that gardeners will be interested in, and if someone that loves flowers were to see one at a garden centre or show, they may be inclined to purchase.
Best of luck- it's a lovely idea. I would say weddings would be a really awesome market. How great would it be to have real flowers in your hair or jewellery to match a bride's bouquet? :)
