O – Ophiopogon, Ornamental Grasses (such as Festuca)
P – Pansy, Primrose
Q – Quince (Chaenomeles), Queen Anne’s Lace (Daucus carota)
R – Rosemary, Rhododendron, Ranunculus (Buttercup)
S – Snowdrop, Skimmia
T – Tulip (early-blooming / flowering varieties)
U – Ulex (Gorse),
Umbrella Pine (Sciadopitys)
V – Viola (Pansy and Viola varieties), Viburnum
W – Winter Pansy, Wallflower
X – Xeranthemum (Beargrass)
Y – Yucca, Yellow Archangel (Lamium galeobdolon)
Z – Zantedeschia (Calla Lily), Zelkova (Japanese Zelkova)