January marks the dead of winter across parts of the Northern Hemisphere. In temperate regions, either the bitter winter cold prevents any plants from breaking dormancy from under the snow, or in milder regions many cool-season flowering plants are coming into their prime. If your climate allows, focus on a mix of winter-blooming annuals, perennials and shrubs to provide you with floral delights.
Often pansies and violas, sometimes called Johnny-jump-ups, are planted in autumn and allowed to establish before winter sets in. In U.S. Department of Agriculture hardiness zones 7 through 9, pansies continue to flower across the mild but light, subfreezing weather in January. If temperatures rarely drop below 25 degrees F in January, snapdragons (Antirrhinum spp.), wallflowers (Erysimum spp.), pinks (Dianthus spp.) and annual phlox (Phlox drummondii) may work beautifully in flower beds.
Just like with annual flowers, the severity of weather in January affects how early some winter-blooming perennials and bulbs actually flower. Generally speaking, expect Lenten roses (Helleborus spp.) to flower in late January. Many "spring" bulbs will poke up and bloom on the warmer, sunny January days, too. Snowdrops (Galanthus spp.), winter aconite (Eranthis spp.) and crocus (Crocus spp) can bloom, as can the deeply colored dwarf irises (Iris histroides and Iris reticulata). Don't forget the earliest blooming varieties of daffodils (Narcissus spp.) as well. Once January-blooming daffodil do try to grow, it is named "Rijnveld's Early Sensation."
The quintessential shrub to grow to boast flowers in January is the camellia. Common or Japanese camellias (Camellia japonica) and many hybrids overlap their flowering seasons in January. Thus, you can enjoy the tail-end of fall-flowering varieties as well as the middle and early parts of the flowering season of others. Witchhazels, although deciduous and resembling vase-shaped small trees, start bearing golden to rust-colored, ribbony flowers in January. Many varieties' flowers emit a sweet or spicy fragrance, too. Winter daphne (Daphne odora) and various species of mahonia (Mahonia spp.) can bloom in January alongside perennials if the weather isn't too cold and dreary. If you are fortunate enough to live in a mild Mediterranean climate, wattles/mimosa (Acacia spp.) bear golden flowers in midwinter. Subtropical gardeners in southern Florida, for example, can witness the beginning of the bloom season for yesterday-today-and-tomorrow (Brunfelsia spp.), shaving brush trees (Pseudobombax spp.) and the Hong Kong orchid tree (Bauhinia blakeana).