A Daisy a Day
The Flowers That Bloom In The Spring, Tra La
April Showers [...they bring the flowers that bloom in May...)
Erev Shel Shoshanim (Evening of Roses)
Carolina In The Morning (...where the morning glories twine around my door ...)
Cherry Pink and Apple Blossom White
Sakura (Cherry Blooms)
A Blossom Fell

Is it "Fill Me Up, Buttercup" or "Build Me Up, Buttercup?"

Moonlight and Roses
You Don't Bring Me Flowers
Aloha Oe (not "about flowers" as such, but the first verse features the ahi hile hua, which, I understand, is a beautiful flower)

Song of the Islands has a line about Hawaii's "fragrant flowers"

Genie