How To Grow Hydrangeas

Lynn Coulter
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Susanne Hudson's hydrangea garden in Douglasville, GA

If you want a garden that explodes with color, you can’t miss with hydrangeas. These carefree shrubs open their big, beautiful flowers every summer, adding pops of pink, blue, lavender, and snowy-white to the landscape.

Susanne Hudson is a gardener and interior designer in Douglasville, GA, who grows over 200 of these spectacular shrubs around her restored Greek Revival home. If you haven’t read my interview with Susanne yet, please visit Hydrangeas For Every Garden. Meanwhile, here are a few things you’ll want to do before you reach for a shovel to plant hydrangeas in your yard:

  • Choose the right location. Hydrangeas like moist, well-drained soil, and most need partial shade, especially in hot climates. (Avoid deep shade, though, or you won’t get many flowers, and don’t plant directly under trees, where the roots would compete for water and nutrients). In general, hydrangeas can take more sun in northern climates than in southern parts of the U.S. Read the tag on your plant to be sure you’re giving it what it requires.

  • Plant after your last spring frost. Many hydrangeas bloom on the previous year’s growth, so a late freeze will kill new flower buds. (How do you get avoid a freeze? If you know the answer to that, let me know. I bet the National Weather Service can find a job for you.) Or grow re-blooming hydrangeas, like those in the ‘Endless Summer’ collection. Proven Winners ‘Incrediball,’ which you can find on The Home Depot’s Shrubs and Hedges  page, is another good choice. These plants bloom on the current year’s growth, so you’ll be sure to get flowers. Gardeners who don’t get hit by a cold snap will get two flushes of flowers each season.

  • Dig a hole at least two to three times the size of the plant’s root ball. (I know, I know. Digging isn’t fun, but don’t skimp on this step. Just make sure you have a good shovel, or ask a neighborhood teen for help, maybe in return for borrowing your new video game for a few days.) If your soil is like the rock-hard Georgia clay that makes my shovel bounce, add some compost, aged manure, perlite, or other soil amendments.

  • Water thoroughly after planting, and mulch to retain moisture.

  • Many hydrangeas don’t need fertilizing, because the nutrients in the soil are sufficient. However,  you can use a slow release fertilizer or a 10-10-10, applied in early spring and again in early fall. Just don’t overdo it, or  you’ll have lush, green leaves–and you’ll wind up visiting the florist when you want flowers.

Hydrangeas For Your Region

If you live and garden in the northern U.S., try Hydrangea paniculatas, which are the most cold hardy hydrangeas. ‘Limelight,’ ‘Pinky Winky,’ and ‘Grandiflora,’ also known as ‘PeeGee,’ are great choices for USDA hardiness zones 4 through 7. Some gardeners can grow ‘Annabelle,’ H. arborescens, as far north as zone 3. ‘Annabelle’ is a lovely cultivar with flowerheads that can grown as big as a foot in diameter.

In the southeast, try oakleaf hydrangeas, H. quercifolia, one of two hydrangea species that are native to the U.S. Oakleaf hydrangeas are best suited for moist woodland gardens, or the edge of woodlands. Their foliage takes on shades of deep mahogany, green, and rust in autumn, and the peeling bark is very attractive.

Smooth hydrangea, H. arborescens, is the other native American species. It’s rated for USDA hardiness zones 4 to 9 and grows from New York to Florida, and west to Iowa and Louisiana.

Gardeners in zones 4 to 7 can also grow climbing hydrangea, H. anomala petiolaris. This is a clinging vine that grows slowly, but eventually reaches 80 feet in height, if grown onto a structure. (Warning: it’s difficult to pull these plants down, if you decide to remove them, and they leave marks. Use them only where you want them to remain.)

 Southern gardeners can grow the old-fashioned mopheads, H. macrophylla, also called the bigleaf, French, garden or florist’s hydrangea. Mopheads are rated to USDA cold hardiness zone 6.

Gardeners in zone 10 can try hydrangeas in containers. Grow them in the shade or in cool sunrooms.

Susanne Hudson’s Tips For Hydrangeas:

  • Try growing hydrangeas in pots for your porch or deck. Use a big container and lots of dirt, so you won’t have to water often.

  • If your garden gets a lot of sun, don’t despair. There are hydrangeas for both sun and shade.

  •  The pH of your soil determines whether you get pink or blue flowers on many hydrangeas, You can change some hydrangea blooms from blue to pink by adding dolomitic lime to your soil, or from pink to blue by using aluminum sulfate. Susanne doesn’t tinker with the soil. “I leave the color to Mother Nature, and it turns out great.”

  •  Want something in your potted hydrangeas to look at during the winter? Add a small evergreen to the container.

    • Add a few old farm tools, like rusty hoes or rakes, to your pots. Look for them at yard sales, or use whatever you have. Susanne substitutes metal poles for the original wooden handles, so the wood won’t rot, and sticks the tools into the pots upside down. Voila—you’ve got a vintage-look “tool bouquet.”

 

 

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