Overwintering Perennials in Cedar Boxes on a Toronto Deck

Shallow cedar boxes cannot protect perennial roots from freezing solid in Toronto's zone 5/6 winters. Even hardy perennials have roots that are far less cold‑tolerant than their tops.

Better Alternatives

• Hardy annuals: They provide season‑long color without winter‑care hassles. Consider moonflower (evening scent) and 'Heavenly Blue' morning glory.
• If perennials are a must: Move boxes to a protected, unheated garage or shed, insulate heavily, and water sparingly.
• Clematis: A perennial vine that can bloom all summer if given a large enough container and winter protection.

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