Throughout spring and summer, the classic cloud-like blooms of the hydrangea charm across North Carolina. It’s no surprise that many gardeners choose to plant the shrubs — with their vibrant pink, blue, lilac, and white flowers — near their front doors as a subtle sign of Southern hospitality. But as friendly as the hydrangea appears, many novice gardeners feel intimidated by the idea of growing the pretty plant. What can you do this fall to ensure your hydrangeas impress next year? Amy Ballard, a Commercial and Consumer Horticulture Extension Agent in Davidson County, has a few tips.
1. Do a little homework.
The best way to start is by getting to know your plant. Some cultivars, or “flavors of hydrangea,” as Ballard describes them, produce a different bloom style. The most common is the mophead hydrangea, which produces the iconic fluffy head of blossoms. Lacecap hydrangeas produce a similar shape, with a small bud in the center of each blooming flower. If you prefer a cone-shaped plant, the oakleaf hydrangea might be for you.
2. Spot the perfect plot.
“Proper site selection is key,” Ballard says. Choose a site that is well-drained and receives the correct amount of sun. Hydrangeas are the Southern belles of the plant world — they love the sun but prefer dappled shade in the heat of the afternoon.
3. Put the soil to the test.
Soil pH mainly affects the bioavailability of nutrients, but it also affects bloom color in hydrangeas, Ballard says. Acidic soil produces more vibrant flowers, while alkaline soil produces paler blooms. To turn pink flowers purple, Ballard recommends adding aluminum-sulfate products (which can be purchased at most garden stores) to the soil to create a more acidic environment for the plant.
4. Find the best fuel.
Ballard recommends a hydrangea-specific fertilizer, but notes that a 10-10-10 fertilizer is a good alternative. For dosage, it’s best to follow the results of your soil test to ensure that the nutrient percentages are align for a healthy bloom.
5. Go easy on the mulch.
Mulch helps soil retain water and wards off pesky weeds, but over-mulching proves that you can have too much of a good thing. According to Ballard, mulch should be no more than two to three inches deep, keeping the crown of the plant about an inch away from the mulch. Pine straw is a great option because it doesn’t affect soil pH; pine bark will also work, but may bring down the soil pH, which means you’ll need another soil test after about one year.
6. Learn to prune prudently.
When given enough room to spread out, hydrangeas may not need pruning at all. Expect your hydrangea bush to spread out as it grows, and plant accordingly. The best way to avoid over-pruning is to stick to deadheading when a bloom begins to fade. If you notice that your plant is growing unevenly, Ballard suggests cutting back some of the uneven sides during the late fall.
7. Keep the cuttings for heirloom planting.
In the spring, hydrangea stems grow longer and bud more. At this point, conditions are ripe for creating an entirely new plant. Simply cut a stem from the plant, apply a growth-hormone powder to the end, dip it in water, and insert it in soil.
Have more questions? Contact the NC Cooperative Extension of Davidson County
(336)249-7300 or davidson.ces.ncsu.edu