JAPANESE MOUNTAIN HYDRANGEAS are hale and hardy.
Bud hardy yet very feminine. High maintenance? Not these ladies. In 10 years they have bloomed every year for everyone I have planted. They remain dormant longer and avoid late frosts. Generally they are somewhat smaller than the H. macrophylla.

H. serrata 'Shirofugi'
This is a 3ft shrub. Flower heads are perfectly white double stars. A beautiful perfection.

Like their 'French' cousins they like good drainage, good soil and water and fertilizer. But you don't have to hover over them. Just plant them well to begin with and water once a week. Give them acidity, (sulphur) for better blues and alkalinity, (lime) for more pinks.

Don't trim them. Just cut yourself some bouquets. Do yourself a favor...grow some of these. You don't have 15 years to waste.

Zone 6-10.

Just did a google search and found there is big confusion out there about the name. I found 'Shirofugi' as well as 'Shirofuji'.
Dave's Garden has 'Shirofugi', I trust them most. But in any case this is a beautiful hydrangea.