Growing Green

By Robin Trott, Extension Educator

Every year, I’m amazed by the hydrangeas blooming on our farm and fall in love with this incredible shrub all over again. While many flowers wilt in the summer heat, hydrangeas thrive with stunning blooms! Growing up on the East Coast, I was used to beautiful blue and pink hydrangeas, but few of those varieties can survive our northern climate. However, you don’t have to give up on hydrangeas entirely – you just need to choose the right types for a northern garden.

Hydrangea paniculata is a hardy, reliable shrub that thrives in colder climates. Its flowers aren’t vulnerable to frost damage because they bloom on new wood. The plant usually has tall, cone-shaped flowers. One of the most popular varieties is “Limelight,” a fast-growing shrub that blooms in mid-summer. Hardy to zone 3, this 7-foot-tall shrub produces pistachio-hued flowers that turn deep pink as they age. Other varieties include “Pinky Winky” (bi-colored pink and white), “Quick Fire” (cream to deep red), and “Firelight” (white to deep red). These varieties don’t need extra lime to maintain their pink color.

Hydrangea arborescens, or smooth hydrangea, is a widely branched deciduous shrub that typically grows 3-6 feet tall. “Annabelle” is a popular variety, known for its enormous white flower heads that bloom in mid-summer and dry to a brilliant green. “Incrediball^®” offers huge, strong-stemmed flowers with round clusters more than a foot in diameter! This shrub was bred to improve the stem strength of hydrangeas, which often flop under the weight of large blooms. Other varieties include “Invincibelle Spirit” (pink) and “Haas Halo” (white, similar to lace-cap).

Although beautiful, Hydrangea macrophylla (lace cap hydrangea) and Hydrangea quercifolia (oak leaf hydrangea) are only hardy to zone 5 and aren’t suitable for our northern gardens.

Hydrangeas are easy to grow in rich, well-drained soil. They prefer morning sun and afternoon shade. Avoid planting them in hot, dry, exposed areas. Although most people buy hydrangeas when they’re blooming, it’s best to plant them in spring or fall. Prune in late winter or early spring before new growth begins. To get bigger flowers, prune them almost to the ground, leaving a 2-4-inch stem.

For more information on growing hydrangeas in your garden, contact the University of Minnesota Extension, Douglas County, at 320-762-3890.

Until next time, happy gardening!

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“Dragoons, I tell you the white hydrangeas turn rust and go soon.

Already mid-September a line of brown runs over them.

One sunset after another tracks the faces, the petals.

Waiting, they look over the fence for what way they go.” ~ Carl Sandburg