When many plants have died down for the season, cool-weather bloomers emerge to light up the landscape and provide warmth and color to the garden. Grown in a wide range of shapes and sizes, many cool weather plants are frost-tolerant. They withstand cool fall temperatures and snowy winters. Tucked along a perennial bed or lining a garden walkway, cool-weather plants are a garden staple for those who crave year-round color.
Hellebore (Helleborus orientalis) is a late winter-blooming herbaceous perennial flower that has a clumping growth rate. Also called Lenten rose, hellebore grow up to 1-1/2 feet tall and wide, making for an ideal border flower. The 3-to-4-inch-wide, cup-shaped, nodding, rose-like flowers have contrasting yellow stamens. The large hellebore flowers appear in clusters of one to four along the thick, rising stems. The shades of color on hellebore flowers vary from pink to pale rose and purple, with some smattering of interior spots. The 8-to-16-inch-wide, serrated, leather-like, glossy foliage are comprised of the seven to nine, dark green leaflets. As an evergreen, hellebore remains vibrant throughout winter to provide a burst of color to the garden. The blooms continue to unfold in spring and are known as true harbingers of spring. Hellebore grows best in part to full shade and well-drained, humus-rich soil. They are suitable in USDA zones 4 to 9.
Snowdrop (Galanthus elwesii) is a perennial bulb that blooms from late winter until spring. Low-growing, it reaches a maximum height of 1 foot and a spread of 1/2 foot. The common name, snowdrop, is in reference to the striking resemblance of the flowers to tiny drops of snow. Each snowdrop bulb creates two to three narrow, 1-1/4 inch-wide, basal leaves that grow up to 4 inches long once the snowdrop has flowered. The 2-inch-long, nodding, white, bell-shaped, single flowers of snowdrops appear as if they are bowing down to the garden. Snowdrops grow best in full sun to part shade and well-drained, moist soil. According to Missouri Botanical Garden, snowdrop “grows particularly well under deciduous trees where exposure to the sun is full in early spring but gradually changes to part shade as the trees leaf out.” Plant snowdrops in USDA zones 4 to 7.
October Skies Aster
October skies aster (Aster oblongifolius 'October Skies') is a perennial flower with a spreading growth habit and moderate growth pace. October skies flowers in fall, when many plants have died down for the season. They grow 1 to 3 feet tall and wide and have a mounding, low to the ground form that makes them ideal along beds and borders or tucked into containers. The daisy-like, sky blue flowers of October skies aster have a contrasting yellow center to grow in masses during fall. Frost-tolerant, October skies asters withstand periods of cool weather but without sacrificing their vibrant blooms. They grow best in full sun to part shade and are suitable in USDA zones 4 to 8.