I always say, these are YOUR photos, so make sure you are comfortable and wearing clothes that reflect you as a family! Having said that, it's a great idea to put a little bit of forethought into what you're going to wear, so that your images show you all off in the best light and we take advantage of the beautiful backdrop of bluebells.
Amongst the bluebells, you will be surrounded by the acid green of the bluebell foliage as well as the vibrant purply/blue of the flowers themselves.
It's a great idea to choose a clothing colour scheme that fits in with these base colours so I can highly recommend neutral tones - such as pale pinks, greys and creams. Other spring colours can look beautiful as well - whites, pastle yellows and light blues.