Not dead, only sleeping: plant dormancy
What is plant dormancy?
Plant dormancy is when a plant will stop most if not all activities. This may be accompanied by dying back to the ground for herbaceous plants, or dropping all leaves in the case of deciduous trees and shrubs. It is the equivalent of hibernation in most animals, and it is an important survival mechanism that plants possess.
Dormant perennials may appear dead above ground
Why do plants go dormant?
Plants will go dormant here in North Carolina when the weather begins to shift, becoming much colder and with reduced hours of sunlight. Leaves and other soft tissues can be easily damaged by frost, which is why many plants will retreat underground to their root system, where the soil and leaf litter/mulch provides protection from truly freezing. Woody plants will convert the new season’s growth into woody twigs, and set buds for next year.
However, cold weather is not the only reason a plant will go dormant, stress is another factor:
Heat and drought
Excessive browsing/feeding damage
Transplant shock
New spring shoots emerging
Why is dormancy important?
Dormancy is not only important for hibernation, but also important for:
Setting new buds for the next season
Developing flowers for spring blooms (especially fruit trees)
Initiating maturity for perennials
Releasing seeds from germination inhibitors
Promoting overall rejuvenation for the next growing season
New spring shoots emerging
Do evergreens go dormant?
While they may not drop their leaves like deciduous plants, evergreen plants still go through dormancy. They produce no new growth during this time, and will often shed old leaves, needles, or scales every few years. This is normal, as old leaves and structures are less efficient and may become shaded by new growth.
Close up of evergreen plant
Dormant vs. dead, how to tell the difference
In situations of stress, or excessively cold temperatures it may become a question of has the plant died or not. This is harder to determine for herbaceous plants, which is really best done through waiting for new growth. Woody plants can be tested by either gently bending the tips of branches, or scratching away a small amount of bark. Snapping indicates death, as does lack of green pigment below the bark.
Healthy green under the bark
Possibly dead, brown under the bark
Caring for dormant plants
Dormancy can be a vulnerable time for plants. If treated incorrectly, they caan die instead of growing back. At this time, most plants require significantly less water and nutrients. As such, it is best not to fertilize and keep irrigation to a minimum unless particularly dry conditions emerge and persist.
New growth from the base after dieback
