Instead of painting the bicycle how about putting a basket attached to the front of the handlebars that you could change out with artificial flowers/ greenery to go with the flowers or the seasons when the flowers aren’t in bloom?

Better still use real flowers. The same as in the bed. Or, since the flowers in the ground are a random mix, it doesn't really matter what colour you pick for the bike. Choose a colour you like and match the flowers to it.

Yes, leave the bike itself alone and add a basket on the front. Line it with a coconut/coir liner (available almost everywhere that sells hanging baskets) and plant flowers in it. What flowers do you have in the ground? Get more of those.