Hydrangeas are having a good year.
I’m noticing a stronger-than-usual show. The blooms seem fuller and the colors more vibrant. That could be thanks to the mild winter we had, along with a warm, steady spring without late frosts.
Let’s begin with the most common hydrangea in the Lowcountry, the big leaf hydrangeas. The glossy foliage often tends to shine when happy. The flowers come in two types: mophead are the iconic flower balls, while lacecaps are less common and more unique with florets arranged around the perimeter of a flat flower.
Older varieties like “Nikko Blue” bloom only on old wood, so last year’s weather and your pruning habits determine what happens this summer. In general, don’t prune after July 4 to avoid removing flower buds developing for the next year. Newer cultivars like “Endless Summer” bloom on both old and new wood, offering more reliable flowers regardless of pruning mistakes or weather surprises.
Big leaf hydrangeas thrive in morning sun and afternoon shade. Too much sun can stress the plant. What makes them especially interesting, though, is how their flower color responds to soil pH. Acidic soils with a pH below six tend to produce blue flowers. Alkaline soils, with a pH above seven, bring out pink tones. If your blooms are somewhere in the middle, so is your pH.
Big leaf hydrangea with mophead flowers are the iconic flower balls.
Tony Bertauski/Provided
Want to experiment? To push toward blue, you can add garden sulfur to lower the pH, ideally in fall or early spring. To encourage pink blooms, lime will help raise the pH. Change takes time and depends on your starting soil. Always test first so you know where your pH is beginning. And do not overdo it. A little goes a long way.
Next up is panicle hydrangea with duller foliage than the big leaf hydrangea. They produce cone-shaped flower clusters that open creamy white and often blush pink as they age. Unlike big leaf hydrangeas, these bloom on new wood. You can prune them in late winter and still get a full summer show. They also tolerate more sun and are generally less fussy.
“Limelight” is a local favorite for good reason. It thrives in full sun, handles our humidity and produces large, mophead blooms that hold up well into fall. For smaller spaces, “Little Lime” offers the same charm in a compact package. I’ve had great effect in my backyard with “Pinky Winky,” which shifts from white to pink to dusty rose as the season progresses.
For a native selection, consider the oakleaf hydrangea. The enormous leaves are coarse and resemble an oak leaf. The form is much more irregular and these do well in naturalized areas. The flowers are long and elegant. The bark exfoliates in winter, and in autumn the foliage turns burgundy and crimson.
These hydrangeas thrive in part shade and prefer well-drained soils. Because they bloom on old wood, they also benefited from this year’s forgiving winter. I’ve noticed oakleaf hydrangeas doing much better in the Upstate, but that shouldn’t dissuade you from working them into your Lowcountry landscape. Success can be hit or miss.
Panicle hydrangea is a “Limelight” cultivar. It thrives in full sun, handles our humidity and produces large, mophead blooms that hold up well into fall.
Tony Bertauski/Provided
Another native to consider is smooth hydrangea. It is more common Upstate and requires more attention in the Lowcountry. I haven’t had any long-term success with it but have enjoyed seeing it when hiking in cooler regions.
Unlike bigleaf and oakleaf types, smooth hydrangea blooms on new wood, making it dependable even after tough winters. The plant prefers part shade and moist, well-drained soil. You can prune it back hard in late winter to encourage a fuller shape and bigger blooms. Like oakleaf, smooth hydrangea offers a wild, naturalistic look that works well in woodland borders.
Hydrangeas love mulch to keep their roots cool and moist. Water them deeply during dry spells. Most importantly, know when to prune. Old wood bloomers should be pruned after flowering. New wood bloomers get their haircut in late winter. Enjoy the results!