Most hydrangeas are reasonably hardy, and can tolerate temperatures right down to -10°C. Sometimes even lower, once they’re properly established, but they still require some help over the winter months to ensure a beautiful flush of flowers next year, and the secret to ensuring that is adding a layer of mulch right now to overwinter them.
Overwintering essentially means giving plants extra protection to help them survive the winter. If you don't put the effort into protecting your hydrangeas now, you could risk having no blooms next year at all. ‘Because many hydrangeas bloom on last year’s wood, losing those buds is a huge deal; it means you won’t get any blooms in the summer,’ explains Christopher O’Donoghue of Gardens Revived.
