From America’s Expert Source for Heirloom Flower Bulbs
It’s easier than it looks! The American Daffodil Society and Royal Horticultural Society use a simple code to provide shorthand descriptions of daffodils.
Each coded description starts with a number which refers to the “division” the daffodil belongs to based on its ancestry and form:
1 = trumpet (center of the flower is as long or longer than the petals),
2 = large cup (center is from 1/3 to as long as the petals),
3 = small cup (center is less than 1/3 as long or broad as the petals),
4 = double (with extra petals, like a peony, etc.),
5 = triandrus (descended from N. triandrus, pendant flowers, petals swept back, usually white),
6 = cyclamineus (descended from N. cyclamineus, petals swept back, usually yellow),
7 = jonquilla (descended from N. jonquilla, small cups, usually yellow, very fragrant),
8 = tazetta and poetaz (descended from N. tazetta, small cups, cluster-flowered, fragrant; poetazes include N. poeticus genes and are hardier),
9 = poeticus (descended from N. poeticus, white petals, small “pheasant’s-eye” cup, late-blooming, fragrant),
10 = bulbocodium (descended from N. bulbocodium (small flowers, “hoop petticoat” form)
11 = split corona (center split into segments and laid against the petals)
12 = other cultivars (not falling into any of the previous divisions)
13 = wild species and wild-occurring hybrids
Then there are at least two letters that refer to the daffodil’s colors. The letter or letters before the hyphen describe the colors of the petals (also known as the perianth), starting from the tips. The letters that come after the hyphen are the colors of the trumpet or cup (also known as the corona), starting from the base.
Y = yellow
W = white
O = orange
R = red
G = green
P = pink
So now you know! 3 W-GYO translates as:
3 = a short-cup daffodil (the cup is less than one-third as long as the petals)
W = with white petals
GYO = and a cup that’s green at the base, yellow in the middle, and orange at the rim.
That’s all there is to it. Happy de-coding!