Chrysanthemum
Chrysanthemums, sometimes called mums or chrysanths, are flowering plants of the genus Chrysanthemum in the family Asteraceae. They are native to East Asia and northeastern Europe. Most species originate from East Asia and the center of diversity is in China. Countless horticultural varieties and cultivars exist.
A flower whose name contains seven letters, the second being E, is Gerbera. Gerberas grow in a variety of colors.
The flower with only three letters in its name is the "lily."
The dahlia has 6 letters.
A flower using some of those letters is the blossom of apricot.
Those letters spell carnation.
Frangipani.
aster
A portobella
Petunia.
vase
daisy
Clary.