Jan 13, 2021

Plant Phases - Dormancy

by Melissa, Office Manager

The lotus was considered a sacred flower by ancient Egyptians and was used in burial rituals. This flower blooms in rivers and damp wetlands, but may lie dormant for years during drought, only to flower again with the return of water. Egyptians viewed it as a symbol of resurrection and eternal life. Nature has given plants this incredible restorative state of dormancy.

Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps conserve energy. Dormancy tends to be closely associated with environmental conditions. Dormant seeds are in a state of suspended animation, delaying germination until the conditions are right for survival and growth. For perennial plants, dormancy is triggered when adverse growing conditions are present. It is important to remember that plants are not dead during this time; they are just conserving energy and preparing for the next stage.

Almost all plants go through periods of dormancy, and not all are in the winter. Some plants go through a dormancy period in the heat of the summer to conserve the moisture they need for survival. Grass that is winter-cold hardy often goes dormant in the heat of the summer to preserve moisture. Once the stress has passed, the dormant grass will green up again and come out of the inactive state. When plants go dormant, it is an excellent opportunity to do some late spring pruning before the new growth starts.

Many online nurseries will ship plants in a bare-root or dormant state. When you get a straggly root in the mail, it can seem pretty iffy. But that root has the power it needs to grow into the beautiful plant you want. Just be sure to get it in the ground as soon as possible, so it doesn't emerge from dormancy before it is the right time. 

Some species of seeds can remain dormant for up to 50 years, waiting for the right conditions to present themselves so the plant can be ready to grow. Seed dormancy occurs through a few different methods, some of which happen outside the embryo, others inside it. An example of an external process is a hard seed coat, which stops the seed from absorbing water and sometimes air. The hard seed coat may need to be broken by heat, freezing, or by passing through an animal's acidic guts. Dormancy may also be triggered by factors inside the embryo, especially chemical changes, which need to occur in the seed before it germinates. Some seeds, for example, require a period of light or dark to germinate. 

Gardeners will often carry out processes that imitate these natural ones to break dormancy and get seeds to germinate, for instance, by chilling seeds to imitate cold weather or by applying abrasives to weaken the seed coat. One of the surprising conditions that seeds and plants may need is smoke and fire. We usually think of these as destructive and not necessarily beneficial for life. However, in 2004, researchers in Western Australia conducted a study to discover which chemical in smoke acts as the “phoenix factor” that brings dormant, fire-reliant seeds to life.

The giant Sequoia trees of California have also been studied to find the connection between fire and seed propagation. After a period of extended fire suppression, it was discovered that the sequoia trees were not producing seedlings as expected. They found that Sequoias rely on fire to release the seeds from the cones. It is a fascinating process, allowing the Sequoia to thrive in conditions other trees cannot benefit from in the same way. The fire exposes the bare soil for seedlings to take root, minerals from the ash nourish the earth, and open holes in the forest canopy allow the seedlings to receive the sunlight needed. All while also eliminating the competition from other tree species. It's incredible!

So the next time you see a dormant seed or plant, think of the incredible power it contains and what it can do if provided with proper conditions.