As the birthplace of Carl von Linne--Linnaeus--the tiny Scandinavian nation of Sweden has had an enormous impact on the history of botany. The scientific system of plant classification that Linnaeus introduced in the 18th century is still used today. Sweden itself is home to 100,000 square miles of forests and many species of extremely cold-hardy plants, from evergreen trees to delicate rock garden flowers and vigorous blooming shrubs.
Named for Linnaeus himself, twinflower (Linnaeae borealis) is a member of the honeysuckle family. A creeping perennial reaching as long as three feet, twinflower has sparsely-leave multiple branches with deep green oval leaves. From June to September, twinflower has four- to six-inch stalks bearing nodding clusters of blooms. The small, funnel-shaped pink or white flowers are extremely fragrant.
Widely distributed in the United States, twinflower makes an effective addition to woodland gardens when given enough room, says the Lady Bird Johnson Wildflower Center. Plant it in sun to shade and cool moist, acidic (pH above 7.0) soil high in organic material.
Yarrow (Achillea millefloium), an aster family perennial, is hardy in winter temperatures of minus 40 degrees F. Yarrow grows throughout Sweden in pastures and meadows, along the coast and on farmland. Standing two to three feet high and wide, it spreads by self-seeding and rhizomes (roots) and may become invasive. From June to October, two- to four-inch flat clusters of tiny white flowers top yarrow's stems. The plant's feathery leaves, says the Missouri Botanical Garden, emit a spicy aroma that makes them desirable for dried flower arrangements.
Like twinflower, yarrow grows wild through much of the United States. For best results, plant it in full sun and well-drained, sandy loam. Tolerant of drought and humidity, it will grow in poor soil if drainage is adequate. Cutting yarrow back in late spring before it sets buds to prevent its stems from drooping.
Bearberry (Arctostaphylos uva-ursi), an evergreen shrub hardy to minus 50 degrees, loves the growing conditions in Sweden's bogs, marshes and forests. A slow grower, it stands six to 12 inches high and spreads three to six feet. Bearberry eventually forms an attractive ground cover, advises the Missouri Botanical Garden. Its glossy, dark green leaves bring red color in the winter garden.
In May and June--April and May in warmer climates--bearberry has drooping spikes of bell-shaped, pink-tinged white flowers. Bright red berries follow the flowers, remaining on the plants throughout the winter. Bears, birds and other wildlife feed on them. Plant bearberry in dry to averagely moist, well-drained acidic soil. It prefers sunny to partially shady, sandy infertile locations and will not benefit from fertilizers.