Heavenly hydrangeas

Story by Julia Moore

  • Bobo Bobo Courtesy of Proven Winners - provenwinners.com
  • Endless Summer Endless Summer
  • Grandiflora Grandiflora
  • Annabelle Annabelle
  • Quick Fire Quick Fire

Whether it's for the love of those large, beautiful blooms or for the nostalgia of growing grandma's favorite flower, gardeners can't get enough of hydrangeas. But growing them in Alaska – especially with our fluctuating winters – can be a real challenge. Here are some suggested varietals from pros across the state to get your show-stopping shrubs started.


These two species may not be able to winter over through Alaska’s cold temperatures or bloom to the fullest, but their beauty makes growing them worth the trial and error.
Hydrangea Anomala
Also known as the “climbing hydrangea,” this species is a versatile vine, clinging to structures around it, reaching about 30-40’ long. White, fragrant flowers open early in summer. If testing out this less-hardy species, be sure to lay it to bed with mulch for winter. (Hardiness zone 4)
Hydrangea Macrophylla
Large, lux blooms make the Macrophylla one of the most popular hydrangea species. The flowers bloom on old and new wood, so be sure to prune only after blooming is finished and protect from moose during winter. Tip: Add soil sulfur or aluminum sulfate for bluer flowers or add dolomitic lime for pinker flowers. (Hardiness zone 4+)
Try: Endless Summer, a varietal whose early blooms can continue all summer. (Hardiness zone 4)
Choosing a hardy hydrangea

When planting anything in Alaska, it’s important to keep in mind the hardiness of the plant. Only consider a plant with hardiness 3 or lower in Alaska. In Southeast Alaska or on the peninsula, you may be able to get away with a higher hardiness level. With hydrangeas, you’ll also want to look for species and varietals that bloom early, since our summers are so mild compared to the lower 48.

Hydrangea Arborescens

Also known as the “smooth hydrangea,” this species of hydrangea grows as a compact bush, needing trimming down to about 6-8 inches from the ground in late winter. (Bonus: Those summer moose munches won’t even matter.)

Try: Annabelle, a varietal with stunning white flowers.

Hydrangea Paniculata

Available in several hardy varietals, Paniculata bushes are distinct with large, conical blooms. Trim this early-blooming species in fall, winter or early spring before new blooms form. Tip: By thinning plants to five to 10 shoots per bush, you can achieve larger blooms – if desired, you can even try pruning into a tree form.

Grandiflora (‘PeeGee’): Rapid-growing stalks with white flowers.
Quick fire: Early blooming light pink flowers that transition to a vivid pink.
Bobo: Loaded with white blooms that turn light pink.
• Firelight: White blooms that become red in fall.

Keeping your hydrangeas happy

Plant your hydrangea in a space where it will get about a half a day of sun – giving them some shade in the afternoon. Plant them in an area with well-drained soil and keep the soil moist. If your hydrangea bloom on new wood, like Paniculata or Arborescens, trim them in winter or early spring before they flower. During the summer, cut old flowers when they fade to boost new blooms.

The weight of your hydrangea blooms – if you are lucky – may drag down your plant. Give your hydrangea support either by planting a few of them close together, trimming it less each year so the stalky height defends against rain, or putting a short wire fence (or decorative fence) around the plant.

Intensely cold winters may kill your hydrangea, making the plant difficult to winter over in Alaska. Try putting mulch over your bushes to help protect it against our harsh, variable winters. If you’re taking on the challenge of growing hydrangeas in Southcentral Alaska, be forewarned that if you are in a particularly cold spot, it is difficult to cultivate thriving hydrangeas.

Sources: Brenda Adams, owner of Gardens by Design in Homer (gardensbybrenda.com); Jeff Lowenfels, lawyer, award-winning author and gardener of Anchorage (jefflowenfels.com); Will Criner, garden and facilities manager at the Alaska Botanical Garden in Anchorage (alaskabg.org).