Overwintering Perennials in Three and a Half Steps
Use these three main steps if you want to achieve overwintering success.
Step 1: Choose the right varieties
• Prioritize high-value crops and reliable types (tissue culture, bare root, patented/brand programs, newer seed-derived lines).
• Avoid or minimize overwintering for low-value, abundantly available, or disease-prone crops (e.g., mildew-prone, bacterial-sensitive, or botrytis-prone varieties).
• Some crops naturally show better flower power after overwintering; others may need chilling for optimal bloom.
• Specific guidance on sedums and nepeta: sedums can overwinter well if kept dry and properly selected; nepeta can be challenging but doable with proper culture.
Step 2: Choose the best growing location
• Indoor overwintering is preferred for control; outdoors can work with precautions. Remember, indoor plants require more labor, consistent moisture management, and protection from excessive solar gain.
• Cold frames and tunnels are viable mid-range options with proper coverings and temperature control.
• Outdoors overwintering is zone-dependent; use hardy varieties and protect with covers, moistened pots, and careful monitoring of temperature and moisture.
• Mice management under frost blankets is critical; place bait stations and monitor.
Step 3: Proper culture and growing techniques
• Emphasize building bulk before winter: plant early, feed heavily (avoid excessive salts and ammonia-based fertilizers late season).
• For fall planting, ensure enough time for root/bulk development; long-day perennials benefit from early planting.
• After foliage dies back, avoid excessive trimming that invites diseases; maintain some foliage for energy storage until dormancy.
• Use preventative fungicides at the onset of dormancy and monitor for botrytis during this time.
• Keep foliage dry when watering; use tools like a leaf blower to dry leaves quickly.
• Monitor soil temperature and crown temperature; raise pots on risers to heat the root zone effectively when forcing or waking up plants.
• Forcing vs. natural dormancy: forcing can yield uniform, timely emergence; adjust temperature to wake up plants predictably.
Half-step: Building an effective backup plan (Step 3.5)
• Use First-Year-Flowering cultivars as backup stock. Find our First-Year-Flowering Scheduling Tool here.
• First-Year-Flowering (FYF) perennials offer flower power in year one without overwintering risk and provide flexibility if overwinter crops underperform.
• Examples and tools: First-Year-Flowering cultivars for echinacea, laminar, veronicas, and others; a First-Year-Flowering Tool helps plan timing for liners, transplanting, and finishing.
• The approach provides a cushion against variable spring sales and weather.
Overwintering success hinges on selecting the right varieties, choosing an appropriate overwintering site, and applying rigorous, forward-thinking cultural practices plus a strong backup plan (via FYF options) to maintain supply and quality into spring.
For more tips and tricks, check out our First-Year-Flowering Tool schedules and regional adjustments. Additional videos for production tips and variety highlights can be found on our YouTube page @darwinperennials.