The most beautiful Hydrangea in the world? The gorgeous 'Miss Saori' won Plant of the Year at the 2014 Chelsea Garden Show.

The most beautiful Hydrangea in the world? The gorgeous 'Miss Saori' won Plant of the Year at the 2014 Chelsea Garden Show.

Hydrangea macrophylla Nantucket Blue is a repeat blooming, blue to pink, prolific mophead reportedly hardy to zone 4!

'Nikko Blue' is a classic Hydrangea with flowers ranging in colour from rich, sky blue through lavender to lavender pink.

Hydrangea macrophylla Onyx 'Flamingo' forms beautiful mopheads of baby pink flowers atop dramatic black stems.

Hydrangea macrophylla Onyx 'Flamingo' forms beautiful mopheads of baby pink flowers atop dramatic black stems.

Hydrangea macrophylla Onyx Peacock forms beautiful mopheads in shades of blue, purple, and pink atop dramatic black stems.

Hydrangea macrophylla Onyx Peacock forms beautiful mopheads in shades of blue, purple, and pink atop dramatic black stems.

Hydrangea Onyx 'Zebra' has black stems and mopheads of pure white flowers.

'Penny Mac' is a classic Hydrangea with flowers ranging in colour from rich, sky blue through lavender to lavender pink.

Hydrangea macrophylla 'Dancing Angel' Peppermint Swirl/Sweet Fantasy has unique flowers in blue or pink with darker flecks.

Hydrangea macrophylla 'Pia' Pink Elf is ultra compact growing to just 18 inches tall and 24 inches wide with deep pink flowers.

Hydrangea macrophylla Pistachio is an incredibly distinct bigleaf hydrangea with mixed colours of blue, deep pink and green.

Hydrangea macrophylla Pistachio is an incredibly distinct hydrangea with mixed colours of blue, deep pink and green.

Hydrangea macrophylla Next Generation 'Red Sensation' is a dwarf cultivar to just 2-3 feet high with deep pink to rosy red, mophead flowers.

Hydrangea macrophylla 'Ruby Blossom' is a bigleaf hydrangea with fully double florets on large, mophead of pink, purple or blue.

Hydrangea macrophylla Seaside Serenade Cape Cod is a compact, reblooming, zone 4 mophead with classic blue, purple-blue or pinkish purple flowers.

Hydrangea macrophylla Seaside Serenade Cape Hatteras is compact with ruby red mophead flowers that deepen with age.

Hydrangea macrophylla Seaside Serenade Cape Lookout is a compact, reblooming, zone 4 mophead with ivory white and green flowers blushing pink.

Hydrangea macrophylla Seaside Serenade Crystal Cove is a frilly lacecap cultivar in shades of deep purple blue, lavender purple, or deep pink.

Hydrangea Seaside Serenade Fire Island is a stunning mophead cultivar with heavily ruffled white florets edged in rosy red maturing to deep pink.

Hydrangea macrophylla Seaside Serenade Glacier Bay is a stunning, compact, reblooming lacecap cultivar with icy white florets on jet black stems.

Hydrangea Seaside Serenade Hamptons has gorgeous mopheads in unusual pink tones including coral pink, icy pink, and pink pink.

Hydrangea macrophylla Seaside Serenade Martha's Vineyard is a compact, reblooming, zone 4 mophead with glowing, almost neon pink flowers.