Why Hydrangeas Are Everywhere
Hydrangeas are the most popular flowering shrub in American landscapes, and for good reason. They produce massive flower clusters (some varieties up to 12 inches across) from early summer through fall. They grow in sun or partial shade. Most varieties are hardy in zones 3 through 9, covering nearly the entire US. And the bigleaf varieties (Hydrangea macrophylla) change flower color based on soil pH: blue in acidic soil, pink in alkaline.
The downside is pruning confusion. Different hydrangea types bloom on different wood (old wood vs new wood), and pruning at the wrong time removes next year’s flower buds. Understanding your variety is the single most important thing for successful hydrangeas.
Hydrangea Types at a Glance
| Type | Blooms On | Prune When | Zones | Example Varieties |
|---|---|---|---|---|
| Bigleaf (macrophylla) | Old wood | Right after flowering | 5 to 9 | Endless Summer, Nikko Blue |
| Panicle (paniculata) | New wood | Late winter to early spring | 3 to 8 | Limelight, Little Lime, Quick Fire |
| Smooth (arborescens) | New wood | Late winter to early spring | 3 to 9 | Annabelle, Incrediball |
| Oakleaf (quercifolia) | Old wood | Right after flowering | 5 to 9 | Snow Queen, Ruby Slippers |
| Climbing (petiolaris) | Old wood | Right after flowering | 4 to 8 | Climbing Hydrangea |
Basic Care
Most hydrangeas perform best in morning sun with afternoon shade, especially in zones 6 and warmer. Full sun is fine in cooler climates (zones 3 to 5) or for panicle types, which are the most sun-tolerant. Water deeply once per week during the growing season. Hydrangeas wilt dramatically in heat but recover quickly with watering. Mulch 2 to 3 inches around the base to retain moisture and regulate soil temperature.
Fertilize once in early spring with a balanced slow-release fertilizer (balanced (such as 10 10 10) or similar). Avoid high-nitrogen fertilizers, which promote leaf growth at the expense of flowers. For bigleaf varieties where you want blue flowers, apply aluminum sulfate to lower soil pH below 5.5.
