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Iowa Gardening: The Hydrangea Hunt

 

Discovering the Best (and Possibly Bluest)
Bloomer for Your Iowa Garden

Story by Veronica Lorson Fowler

What’s not to love about hydrangeas? They are low-maintenance shrubs that each summer showcase huge clouds of tiny flowers in white or pink, sometimes purple or pale green, or — in the right conditions — a coveted sky blue. The blooms are long-lasting, stunning in a vase, and so easy to dry that they often do so right on the plant. (Winter interest, anyone?) Good-looking foliage from spring through fall, when leaves often turn wonderful golds and russets, adds to the appeal. Some hydrangeas even spread, so you can dig up root slips and share with friends.

The trick to successfully growing hydrangeas in Iowa, as with any horticultural endeavor anywhere, is choosing the right plant for the right spot.

Good Bets

Several types of hydrangeas perform beautifully in Iowa because they bloom on current season’s growth.

Smooth hydrangea (Hydranagea arborescens) is a U.S. native that produces big, white clouds of flowers. ‘Annabelle’ is an old-time favorite, a sure bet for any Midwestern garden. It will do well in full sun and grows to 6 feet tall. It spreads readily — so much so that you might need to dig up its edges to control growth. (Give the divisions to friends!) Invincibelle Spirit is a newer type that boasts pink flowers, as does Bella Anna, a member of the Endless Summer collection that blooms on both old and new wood.

While most hydrangeas do well in shade, panicled hydrangeas (Hydrangea paniculata) prefer sun. The most cold-hardy (Zone 3!) of all hydrangeas, these plants boast distinctive cone-shape blooms and can reach 8 to 10 feet tall. (‘Grandiflora’ — nicknamed peegee for the initials of its species and cultivar— can double that reach.) Panicle hydrangeas are sometimes pruned into tree form.

Most bloom white, but ‘Limelight’ offers a wonderful, fresh lime green tinge to opening flowers. (Little Lime delivers the same refreshing color in compact form.) You can introduce more color by trying the white and soft pink of Pinky Winky, the cream-to-pink-to-fuchsia combo of Vanilla Strawberry, and the transformative palettes of white-to-pink Quick Fire and white-to-burgundy-red Mystical Flame.

Oakleaf hydrangea (Hydrangea quercifolia), another native, grows 3 to 8 feet tall and is so named because its leaves are indeed shaped like the leaves on an oak tree. It has big, showy, creamy, cone-shape flowers, but many gardeners plant this variety just for the rich, red-burgundy foliage in fall and revealed cinnamon-brown peeling bark in winter. A note of caution to gardeners above Highway 30: The oakleaf hydrangea is not reliable in Zone 4.

Sowing the Blues

And how about those magnificent blue blooms that grace magazine covers? Better known as bigleaf and sometimes referred to as French, Hydrangea macrophylla is the most sought-after hydrangea. It has nice, big green leaves and puffy flowers about the size of softballs. Gardens with moist settings, acidic soil, and mild winters (conditions usually found along the East Coast) have long produced jaw-dropping showstoppers with large clouds of azure.

Past attempts by Iowa gardeners to paint their landscape in vivid blue (often trying ‘Nikko Blue’) produced primarily disappointment.

And then came the Endless Summer hydrangea series. The Original, introduced by Bailey Nurseries in 2003, ushered in a new era — hydrangeas that bloom on both old and new wood, generating blooms throughout the growing season. These plants are also chameleons, changing color with changing soil pH.

The Original as well as its Endless Summer teammate Twist-n-Shout (a reblooming lacecap), ‘Penny Mac’, and Let’s Dance all have the capacity to be bright pink, bright blue, or shades in between. If you add enough acid to Iowa soil (work in garden sulfur or fertilize with Miracid), flowers will turn blue.

(Due to all that native limestone, Iowa soils tend to be neutral or slightly alkaline. Thus, with no soil modification, these hydrangeas generally bloom pink.) Contrary to popular belief, adding acid to the soil has little impact on the overall health and develop-ment of a hydrangea — only on the flower color.

For now, I am reserving judgment. I’ve tried several Endless Summer The Original hydrangeas in my Ames garden, and my experience has been echoed by some gardeners I’ve consulted. The leaves tend to freeze in early spring, and thereafter the plant merely limps along. A mature plant is supposed to get 3 to 5 feet tall, but mine have all stayed at a couple of feet.

After four years the plants in my garden have not flowered significantly — only a few pinkish blooms. (Editor’s note: Endless Summer confirms reports of inconsistent flower production, especially in cooler climates. Read the company’s consumer advice online at endlesssummerblooms.com > Tips for Blooming Success) Still, others report great success. And even blue blooms!  

Tips for Growing Hydrangeas in Iowa

• Give them light shade to full sun. Hydrangeas are often listed as a shade plant; however, in Iowa we are so far north that our sun isn’t very direct. So these plants can take — and need — more. Full sun is defined as at least six hours of direct sun a day. (Hydrangea macrophylla in Iowa need some sun for good flowering but will wilt in too much.) Most hydrangeas tolerate light shade (three or four hours of full shade or several hours of dappled shade a day).

• Give plenty of water. Hydra is the Greek word for water, and these shrubs do best with lots of it. Position near an outdoor faucet, a low-lying wet area, or at the end of a downspout. Alternatively, plant on top of black plastic buried 2 to 3 feet down, cupped up at the ends to prevent water from draining away.

• Be patient when pruning. Wait until stems are leafing out to cut out any obviously dead wood. Otherwise, cut them back only as needed after they’re done blooming for the season.

• For gardeners missing out on blue flowers, consider wrapping hydrangeas in lightweight superspun landscape fabric (also called floating row cover) in fall after the first hard frost. Remove in late spring after all danger of frost has passed, usually late May. This improves your chances of actually getting flowers. If you’re lucky, they’ll be blue.

Great in the Vase

Hydrangeas are striking in a large vase. They can be mixed with other blooms, certainly, but because the flowers are so big, just a half dozen of them can make an arrangement that will have visitors oohing and aahing.

Cut hydrangeas in the morning after dew has dried and on a day when the plant is well hydrated. (Otherwise, the leaves and petals will be droopy.) Put in a vase that covers at least two-thirds of the stem (remember, these are water lovers). If kept in cool, not bright, conditions, the flowers will last three to five days.

Hydrangeas dry beautifully — right on the shrub, in fact. Simply cut them in early fall, once they’ve dried to an attractive buff color. Use as is in vases or tuck into pots and window boxes for fall decorations. Try spray-painting for shimmering, silvery holiday decoration for mantels, vases, trees, and garlands.

Endless Summer The Original (top) courtesy Bailey Nurseries (baileynurseries.com)

 

 

 

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