Here’s three reasons why and three good alternatives:
1) Not hardy. Proven Winners, the cultivator and grower of many popular “Blue Hydrangeas” states that their hydrangea macrophylla aka “Endless Summer” aka Big-leaf Hydrangeas are not hardy in Minnesota. Some may come back but why risk it when there’s many alternatives?
2) Not proven. Search Google for “problems with blue hydrangeas”. You’ll find trimming comments, pH comments however, few mention that there’s hybrid problems. What’s that? Some breeds are just unstable. Just research “featherless chicken breeding”. Some horticulturalists are saying that these hydrangeas just STOP BLOOMING after a few years because they just can’t bloom.
3) Picky. If you are OK with work, fine. Be prepared that these guys need specific pH levels to bloom blue. They must be trimmed at the right time of year. They will need staking and structural support. So, be prepared, there’s nothing wrong with work– just be prepared!
Here’s a few alternatives we love:
1) Peonies: Easy, big blooms, bullet-proof!
2) “Little Devil” shrubs: Colorful wine-colored foliage all season, bulletproof, easy!
3) False Indigo: 3-4′ tall perennials. Unique vase-like shape, easy, big blue blooms!