by Toni Cross, CPH
Seasonal Color Pots / www.seasonalcolorpots.com
"Praise a large domain, cultivate a small estate," wrote Virgil. Woody shrubs, grasses, perennials, groundcovers: practically anything that can be planted in the garden can fill your window box.
Design Considerations: We hardly need to worry about too much sun during our Northwest winters, but you should still consider the light and exposure your boxes will get and choose plants accordingly. Choose plants that work well with the color of your home and window trim. Most should be "evergreen;" that is, plants that have leaves all winter regardless of their color.
Fall/winter window box plantings grow very little, so think big. Choose plants large enough (4-inch and gallon size plants) and plant the boxes fully enough to make them look "grown in."
Plant Selection: When planting your window boxes, it's not the "paint" that matters; it's the "painter." While keeping your planting conditions in mind, how you use the plants matters more than what plants you choose. Create contrast, movement and interest in your window boxes with whatever plants you select.
Bulbs/Annuals: We have limited choices for winter annuals---pansies in the fall and primroses in the late winter---so consider a strong mix of foliage plants with a lighter mix of flowers. Tuck a few low-growing bulbs in your window boxes as well as annual flowers.
Foliage Effects: Evergreen grasses, like Carex dipsacea (Autumn Sedge) and Carex flagillifera (Brown Sedge) take on golden brown colors in the winter. Variegated grasses like Acorus gramineus 'Ogon,' with its yellow variegation, and Acorus gramineus 'Variegatus,' featuring a cream/green mix, brighten shady boxes. Blue grasses (Festuca glauca 'Elijah Blue'), dark red grasses (Ucinia uciniata), and even black grasses (Ophiopogon planiscapus 'Nigrescens) appear at reputable nurseries.
Contrast these fine-textured plants with bold plants like the many types of Heuchera (Coral Bells) now in the trade. A study in contrasts, Heuchera 'Marmalade' is a beautiful warm butterscotch color while Heuchera 'Obsidian' is a rich black/brown. Bergenia (Elephant Ear), another big leaved perennial, can take on reddish tints in cold weather and blooms on a tall spike in late winter/early spring.
Euphorbias are often are sold as 4-inch or gallon plants in the fall as are new species of Hebe. Euphorbias are a medium-textured plant and include upright and trailing forms. Hebe has leaves similar to boxwood and come in purple, variegated and blue-leaved forms. These medium-textured perennials and shrubs make wonderful foils for both fine-textured and broad-leaved plants.
Conifers and shrubby evergreens, like the winter-blooming Camellia sasanqua, often appear in gallon sizes in the fall and transplant easily to the garden later.
Groundcovers like the new cultivars of Ajuga reptans (Bugleweed) can be used as filler between other plants. Vinca major 'Wojo's Gem' is a variegated trailing vinca and a great substitute for ivy.
Visit a reputable nursery in the fall---preferably one with a CPH on staff---and take time to combine plants there and ask questions. Your fall/winter window boxes can be as glorious as any planter full of spring flowers!