After autumn leaves drop, gardeners often “put the garden to bed” for the year. The garden could be forgotten until spring arrives again. However, bright spots in the garden can add visual interest and needed cheer at this time of year.
Winter is an opportunity to highlight structural aspects of the garden as well as provide habitat and food for wildlife at an otherwise lean time. One way gardeners achieve winter interest is by adding plants with colorful evergreen foliage or attractive bark. But we are fortunate in the maritime Pacific Northwest to be able to grow a number of plants and shrubs that brighten the garden with blooms and sweet fragrance during dark winter months.
Most trees and shrubs go dormant in fall and save their blooms for spring or summer. However, some begin blooming in fall or winter. Cooler winter weather will often extend bloom time, with some displays lasting a month or longer. The area west of the Cascade Mountains generally has mild enough winters to grow a wide range of winter-blooming shrubs. Most days stay above freezing, even in midwinter. Although cold spells can kill some floral buds and damage flowers that are open, new blooms often emerge soon after the cold weather ends, returning the plant to glory.
The plants in this publication are hardy enough to grow in the open garden in most locations west of the Cascades, but consider the various microclimates in your garden before planting. Microclimates are areas which can differ in climate in comparison to the surrounding area. These differences can be caused by vegetation, elevation, bodies of water, aspect (the direction an area faces) or slope. Microclimates can make a difference even for small properties. For example, plants placed next to homes or buildings are more likely to resist damage during a cold spell. The added heat from buildings can also change the timing of blooms.
When deciding where to plant late-fall- and winter-blooming shrubs, consider their location in relation to windows or doorways. This way, you can see their flowers while gazing out or while coming and going. Many winter-blooming shrubs are fragrant, so place these plants where you can enjoy the perfume.
Flowering shrubs also boost pollinators, providing nectar and pollen when little is available. Anna’s hummingbirds are year-round residents in western Oregon. They feed on nectar when they can find it but also supplement their diet with insects. Winter-blooming plants can provide them needed carbohydrates.
European honey bees are active right through the winter and visit many flowering shrubs when temperatures rise above 55 degrees F. Although most of Oregon’s 500 species of native bees go dormant in winter, some, including bumblebee queens and several of our solitary mining bees, are active as early as February and March. The pollen and nectar in these blooms are essential to these bees, fueling their search for new nests and provisioning their first brood. Late fall blooms can be critical for late-foraging pollinator species building fat reserves to last the winter.
Note that while many winter-blooming plants produce nectar and pollen, some are shaped in ways that restrict certain pollinator species. Typically, bumblebees and hummingbirds have the longest tongues and can reach down into longer flowers such as currants and heathers.
The following shrubs reliably bloom and add interest during fall and winter in the maritime Pacific Northwest. They are listed roughly in order of bloom, although the length of bloom of individual plants varies greatly. Bloom timing can also vary year to year due to variations in winter temperatures. Warm winters can lead to earlier bloom times.
Bales, S. 2007. The Garden in Winter: Plant for Beauty and Interest in the Quiet Season. Rodale Books.
Bourne, V. 2005. The Winter Garden: Create a Garden that Shines Through the Forgotten Season. Cassell.Buffin, M. 2005. Winter-flowering shrubs. Timber Press.
Hardy, E. 2015. The Winter Garden: Over 35 step-by-step projects for small spaces using foliage and flowers, berries and blooms, and herbs and produce. CICO Press.
Hinkley, D. 1993. Winter Ornamentals: For the Maritime Northwest Gardener. Sasquatch Books.
Pollet, C. 2017. Winter Gardens: Reinventing the Season. Francis Lincoln.
Simeone, V. 2005. Wonders of the Winter Landscape: Shrubs and Trees to Brighten the Cold-Weather Garden. Chicago Review Press.
Verey, R. 1995. The Garden in Winter. Timber Press.