returns in
304
days
Bloom calendar
Nikko Blue
Bigleaf hydrangea, Mophead
At‑a‑glance
- Group/Class: Bigleaf hydrangea, Mophead
- Height × spread: 4–6 ft (1.2–1.8 m) × 4–6 ft (1.2–1.8 m)
- Bloom window: early to mid summer
- Color & flower form: blue to pink mopheads, soil‑dependent
- Fragrance: 0 none
- USDA hardiness: zones 6–9
- Breeder / Year / Origin: unknown, Japan
- Cut‑flower notes: sturdy stems; conditioning essential; wilt‑prone if stems dry
- Pet safety: avoid
How it differs
- Old‑wood bloomer with one main flush.
- Earlier than many modern bigleaf cultivars.
- Larger overall size than compact selections.
Strengths
- Classic, large mopheads
- Good blue in acidic soil
- Strong presence in shade
Care in one minute
Light: morning sun, afternoon shade.
Soil: fertile, well drained; aim pH below 6 for blue.
Water weekly; mulch 2–3 in (5–8 cm).
Remove only dead wood and spent heads right after flowering.
Watch‑outs
- Late frosts can destroy buds in cold zones
- Not remontant; prune only right after bloom
- High pH soils reduce color and vigor
Best uses (tags)
Provenance note
Named for Nikkō, Japan; widely grown since the mid‑20th century. Unpatented with uncertain original breeder.
References
- Missouri Botanical Garden, ‘Nikko Blue’
- NC State Extension: Hydrangea macrophylla species
- ASPCA: Hydrangea toxicity
