In the mid-1980s, a propagator at Bailey Nurseries in Minnesota noticed that one of the nursery’s hydrangeas was setting buds on its new growth. Most bigleaf hydrangeas (Hydrangea macrophylla) bloom from buds set the previous fall. Bailey Nurseries introduced “Endless Summer” (Hydrangea macrophylla “Bailmer”) in 2004. “Endless Summer,” known for cold hardiness as well as repeat bloom, grows in U.S. Department of Agriculture plant hardiness zones 4 through 9.
The Endless Summer Collection comprises four reblooming hydrangeas. “Blushing Bride” (Hydrangea macrophylla “Blushing Bride”) grows in USDA zones 5 through 9 and has white blooms that blush pink. “Twist-n-Shout” (Hydrangea macrophylla “Twist–n-Shout”) is a lacecap that thrives in USDA zones 4 through 9. “Bella Anna” (Hydrangea arborescens “Bella Anna”) is a pink version of “Annabelle” (Hydrangea arborescens “Annabelle) hardy in USDA zones 4 through 9. Flower colors vary according to the acidity or alkalinity of the soil.
Pruning Flowering Stems
The fresh, new stems of “Endless Summer” are a bright green color compared with the old growth, which is woody and the color of parchment. The new growth produces flower buds all season, so when a flowering stem has faded, you can cut it back to half its length to encourage new growth and new flowering buds.
Cutting Back in Spring
In early spring, “Endless Summer” might look like a clump of dead stems, but don’t cut it back to the ground. Because it blooms on old wood as well as new, you’d inadvertently cut off buds that will bloom this season. Instead, let the new growth emerge to hide the older stems. If dead tips remain, wait until early summer to trim them.
Cutting Back in Fall
The right time to cut back “Endless Summer” if you want to control its size or shape is immediately after it finishes blooming in early fall. You can cut off the dried flowerheads then or leave them on the bush for winter and even up the remaining stems. If you cut the plant all the way to the ground, however, you’ll have to wait for flowers until the buds that grow in spring mature.