I grow every species of hellebore except one, so I also have some that bloom later in the season. Depending on the species and variety, hellebore blooms begin in November and continue into April. I now have thousands naturalized in the shade of my woods. Other green-flowered hellebores that bloom in winter are H. viridis, H. odorus, H. cyclophyllus , and H. multifidus. Because I have grown many seedlings from many different sources, I have some forms of H. niger that wait until March to bloom.
Flowers vary in size and shape.
Some are as large as 4 inches in diameter, while others are as small as an inch and a half across. One of my favorite Helleborus orientalis hybrids, 'Old Early Purple', has dusky, dark-burgundy flowers visible in bud by Christmas and in bloom, usually, during January. On the wooded hillside, a dark, black-burgundy form from Elizabeth Lawrence's garden begins to bloom in January. A few other perennials bloom along with the hellebores in my garden during winter's cold. Phloxes bloom all season, seldom in profusion, but always with a few flowers.