QUESTION: How do you tell if a plant is dormant or dead? We had a hard freeze and a lot of our shrubs look dead, but I don’t want to replace them if I don’t have to. Roger E
ANSWER: There are two different types of dormancy. Predictive dormancy, which is usually triggered by a drop in temperature, is when a plant assumes that winter is coming and starts to shut down in advance of its arrival. Consequential dormancy is when a plant goes into dormancy after adverse weather conditions arise.
Plants go into dormancy for good reason, and a species that has dormancy needs cannot be tricked to stay out of dormancy for prolonged periods without negative consequences. If you bring a temperate climate plant indoors, you can get it to grow for about two years straight, at which point it will go into dormancy no matter what environment it is provided with, and that dormancy will be prolonged until the plant has fully prepared itself for the upcoming seasons.
Deciduous plants will shed their leaves and evergreens will stop all new growth. Both indoor and outdoor plants will go into dormancy when they are stressed. If a plant is super dry, it may shed its leaves in an attempt to conserve what little water remains in its system. Many times, dormant plants are discarded because they are believed to be dead, when they are really just waiting for environmental conditions to improve before continuing growth. Whether it is due to stress or winter weather conditions, plants will go dormant as a defense mechanism to keep themselves alive. So, how do you know if a plant is dormant, or really dead?
One method is the snap-scratch test. Grab a twig from the plant, shrub, or tree in question and bend it sharply back upon itself. A dead limb will snap easily, while a living limb will simply bend, showing moist, living wood within. Alternatively, use a knife or fingernail to scratch the bark of a young twig. A living limb will reveal green under the bark and will be slightly damp. A dead limb will reveal brown dry material.
Another way to check whether a plant is dead or just dormant, is to inspect its root system. If the roots are rotten or shriveled, the plant is most likely dead. If the roots are light and supple, then you are in luck, your plant is just in a state of dormancy, and will soon return to growing once more. Sometimes, the root test is challenging to discern, as some roots are dead and shriveled, while others look unaffected. If this is the case, it’s important to check the primary root first and foremost. If the primary root is healthy, then the plant is probably just dormant. In this case, you probably will want to cut off the shriveled or diseased roots entirely, leaving just the healthy roots intact before replanting the plant back into its home.