Understanding Plant Dormancy
A Natural Part of the Growing Cycle
As the seasons change and temperatures drop, you may notice that trees and perennials in your landscape look less vibrant. Leaves may discolour, fall, or plants may seem lifeless altogether. But don’t worry—this doesn’t mean your plants are dead! They’re simply entering dormancy, a natural process that helps them survive the cold months and prepare for a healthy resurgence in the spring.
What is Plant Dormancy?
Dormancy is a period of reduced activity in plants during which growth slows or stops. This is a survival mechanism that allows plants to conserve energy and protect themselves from harsh winter conditions. During dormancy:
- Trees and shrubs shed their leaves, reducing water loss and protecting against freezing temperatures.
- Perennials retreat underground, focusing their energy on the roots rather than above-ground growth.
Dormancy is essentially a plant’s version of hibernation. Even though the plant may appear lifeless, it’s very much alive, just in a resting state.
Dormancy in Trees and Perennials
For trees and shrubs, dormancy often means shedding leaves in autumn. This process begins when shorter daylight hours and cooler temperatures signal the plant to prepare for winter. While the leaf drop and bare branches may look alarming, it’s completely normal and necessary for the plant’s health.
Perennials behave similarly, but instead of shedding leaves, their above-ground parts often wither and die back. Their energy is stored in the roots, allowing them to regrow when warmer temperatures return.
It’s also important to note that some perennials, such as perennial hibiscus, are late to emerge from dormancy in the spring. These plants may not show new growth until well after other perennials have sprouted, so patience is key.
Dormancy Timing for St. Thomas (Zones 6a/6b)
In our region, plants typically begin to enter dormancy in late October to early November as temperatures cool and daylight shortens. This period can vary slightly depending on the specific weather conditions each year. Dormancy typically lasts until early to mid-spring, with most plants waking up around April. Late risers, like perennial hibiscus, may not show signs of life until late May or even early June.
Why Dormancy is a Great Time for Transplanting and Dividing
If you’re planning to divide or transplant a tree, shrub, or perennial, dormancy is the ideal time. Here’s why:
- Minimal Stress: Plants in dormancy experience less stress during dividing and transplantation because they’re not actively growing.
- Focus on Roots: With energy concentrated in the root system, the plant can establish itself in its new location without needing to support active growth above ground.
- Time to Settle: Transplanting during dormancy gives plants a head start on root development before spring growth begins.
Tips for Managing Dormant Plants
- Avoid Overwatering: Plants need less water during dormancy. Overwatering can lead to root rot.
- Mulch for Protection: Add a layer of mulch around dormant plants to insulate roots from freezing temperatures and help retain soil moisture.
- Patience is Key: Some plants take longer to emerge from dormancy. Don’t assume they’re dead if you don’t see growth immediately in spring.
Educating Gardeners: Your Plants Are Not Dead!
Each fall, we receive many calls from concerned gardeners worried that their plants are dead. Discoloured leaves, leaf drop, and bare branches are normal signs of dormancy. Rest assured, these plants are alive and will return in the spring.
Similarly, in spring, don’t panic if some perennials take longer to re-emerge. Late risers like perennial hibiscus, butterfly weed, and some ornamental grasses may take several weeks longer than others to show signs of growth.
Conclusion
Understanding dormancy can help you better care for your plants and avoid unnecessary worry. It’s a natural and essential part of a plant’s lifecycle that ensures their survival and vitality. By recognizing the signs of dormancy and providing the right care during this period, you’ll set your plants up for a flourishing spring season. Happy Gardening!
