Really lovely. I like how you didn't capitalize the letters, but I think that maybe punctuate the end of each sentence to make it clear that they're three different sentences?
I love the opening stanza, as it gives you lovely imagery of a sea of blue/purple bluebells underneath dappled sunlight in a wood. I like the use of 'carpet' in it, as it makes it seem like a seamless covering. I also liked the alliteration of 'forest floor'.
I smiled at the mention of daffodils 'pushing for the sun', as it makes them seem determined to grow.
The final stanza was lovely and refreshing. April is one of my favourite months, the very beginning of summer. But there's a typo on the word 'happiness'. I don't think that you need the e after the i and before the n, although I might be wrong :)
Truly beautiful nature tricube

Reading this reminds me of recent walks through bluebell woods. I tried to capture the swathes of deep indigo but my camera phone failed. Still, if I need reminding, I'll just come back here.

As for the use of lowercase throughout. It is often used and sometimes to good effect. Less is more? I'm sure you've tried a mixture with this and feel lowercase is better. Without this benefit, I may have attempted capitalising Spring, Daffodil and Happiness. Spring because it is a season and the first word of this poem. Daffodil because it stamps the beginning of a new sentence and so nicely dispenses with a full stop. Happiness because it highlights how 'happy' April makes you feel. In the 2nd stanza, would this offer improvement:

Daffodils
give their all
for the sun

Just my thoughts, always nice to read your work.
Take care.

This is absolutely beautiful and full of lovely imagery. I feel it may symbolise more but I cannot put my hand on it.... Take care,
Em x

Interesting form! Have to try it, well penned.