Minnesota gardeners must consider plant hardiness when making their gardening selections. Divided into U.S. Department of Agriculture's (USDA) Plant Hardiness Zones 3 and 4, gardeners in this state must choose plants that can withstand the harsh Minnesota winters. Hydrangeas are summer-blooming shrubs belonging to the Hydrangeaceae family. Hardy in USDA zones 3 to 8, many hydrangea varieties are able to withstand cold temperatures and frosts.
The Grandiflora (hydrangea paniculata) is one of the best cold-hardy hydrangea cultivars. Grandiflora plants in Minnesota generally reach between 8 and 10 feet in height with similar spreads. These hydrangeas require well-drained, loamy soils in partially shady to fully sunny locations. Grandiflora flowers emerge a creamy white color but mature to a pink or a bronze shade. This hydrangea variety blooms in August and September, adding late-summer color to the landscape in shrub borders, woodland gardens or hedges.
The Annabelle hydrangea (Hydrangea arborescens), sometimes called a snowball hydrangea, reaches up to 5 feet in height with a similar spread. This hydrangea variety needs well-drained, moist soils in partly shady planting sites. The Annabelle hydrangea displays creamy white flowers that can reach over 8 inches in diameter. This plant typically blooms in June and July in Minnesota gardens. The Anabelle sometimes needs staking because the weight of the flowers makes the stems droop. This hydrangea variety is often used in mixed shrub borders.
Limelight is a panicle hydrangea (Hydrangea paniculata) that reaches up to 8 feet high and 6 feet wide. The flowers emerge with white petals that age to a lime green color before fading into rose tones. The green foliage turns red in the autumn. This hydrangea needs moist, rich soils that receive full sun to part shade. This winter hardy hydrangea also tolerates hot temperatures and high levels of humidity. The Limelight variety works well in woodland gardens and shrub borders.
The climbing hydrangea (Hydrangea anomala) is a slow-starting vine that reaches up to 30 feet in length. While the climbing hydrangea can successfully grow in Minnesota, the roots must be protected with leaves or straw during harsh winter weather. This plant bears heart-shaped leaves and creamy white flowers that bloom in June and July. These hydrangeas need well-drained soil in partially shady locations. The climbing hydrangea works well as ground covers. It can also be planted to sprawl over stumps, walls and other structures.
Interhydia hydrangeas (Hydrangea paniculata) bloom large, conical flowers in July and August. The flowers emerge white but turn pink shades with maturity. This variety needs well-drained, moist soils and partial to full sun. The Interhydia variety reaches 3 to 4 feet in both height and width. The red stems add color to the winter landscape, while the green leaves turn purple or yellow in the fall. This hydrangea variety works well planted in groups or masses for borders and hedges.