In the heart of Zone 5b, winter has long served as a vital chapter in the life cycle of certain plant species, like milkweed. These plants rely on a period of cold stratification—a prolonged exposure to freezing temperatures—to break seed dormancy and ensure successful germination. However, with winters becoming shorter and milder due to climate change, this natural rhythm is under threat, posing significant challenges to ecosystems that depend on these plants.

Milkweed, the cornerstone of monarch butterfly habitats, provides a striking example. Its seeds need consistent cold to trigger the biochemical changes that prepare them for spring growth. When winters fail to deliver sufficient cold or fluctuate unpredictably, fewer seeds germinate. Over time, this can lead to diminished milkweed populations, shrinking essential habitats for pollinators like monarchs and bees.

The ripple effects extend beyond the plants themselves. Many species, including birds, insects, and mammals, depend on these plants for food, shelter, and pollination. A decline in milkweed, for instance, disrupts the intricate web of life tied to it, cascading through the ecosystem.

Gardeners and conservationists in Zone 5b and beyond are adapting by mimicking cold stratification manually. Refrigerating seeds before planting or cultivating milkweed indoors ensures germination despite unreliable winters. While these efforts are critical stopgaps, they underscore a deeper issue: ecosystems evolved over millennia to align with stable climate patterns, and rapid warming threatens to unravel these delicate balances.

Addressing climate change at its root is essential. Without collective action, warming winters will continue to rewrite the rules of nature, jeopardizing not only cold-stratified plants but the biodiversity that depends on them. Each milkweed seed that fails to sprout signals a broader ecological alarm—a reminder of nature’s fragility and our role in safeguarding it.