There are plenty of girls’ names that are also names of flowers, like Rose, Violet, Iris, Lily, Ivy, Petunia Daisy, Pansy, Dahlia, and of course Hyacinth 
I can’t think of any names of flowers that could be boys’ names or at least gender nuetral
Any such names?
I’m not sure if the smiley after Hyacinth is a recognition of this, but it originally was, in fact, a boy’s name
Still is in Spanish, and I do know several Jacintos. Met a Margarito once as well (Margarita = Margaret, but as a flower = Daisy).
Bud?
There is an example of a flower named after a boy that I do know of. In a bunch of languages, daffodils are known as narcisses, because they were named after Narcissus (as is narcissism). Just like Narcissus (who stared at his own reflection mirrored in the water), daffodils peer down.
Leaf.
There was a film some time ago called The Hanging Garden, in which all the characters are named for flowers. The male lead was named Sweet William.
Life ain’t easy for a boy named Hibiscus.
Guy LaFleur?
Does Timothy count?
Orlando Bloom? 
Definitely Fiorello La Guardia, a former Mayor of New York City.
I thought Hyacinth would be better known. There is a Bri-com Keeping Up Appearances with the lead character Hyacinth. She has sisters, Rose, Violet, and Dasiy, hence the smiley. Guess it’s not as well known as I thought
Isn’t the Spanish name “Jacinto” the equivalent of Hyacinth?
I’ve heard of men named Orris (although fairly far in the past (mid-19th to early-20th Centuries), which is a variation on Iris (though referring mostly to the rhizome in herbalism).
It was in fact my late step-fathers middle name.
When my brother and myself first saw his borth certificate, he was alive at the time, my mother warned us never to call him “flower”
Naturally as sprogs we couldn’t resist, cost us both a clip round the ear:p
…or Sue
Mandrake
Snapdragon (sounds manly, at least)
How about Basil, it is a flowering plant.
There is a genus of orchids called Dracula. Does that count?