In my part of the world, the vegetable garden is winding down for the winter. Actually, I’m always amazed how some of these plants can withstand the cold and continue producing. We’re still harvesting hardy herbs and vegetables from our organic garden in late November.
The wintertime plant defenses are starting to be apparent this time of year in my organic garden. Many plants are exceptionally good at surviving, not just temperature changes but many environmental threats.
3 Plant Defenses
Thorny Waxy Leaves of
Zanthoxylum nitidum (Roxb.) DC
Some have thorns to ward off animals (useful for protecting your vegetable garden). Some have thick bark, or thick hair, or wax on their leaves.
Some even build themselves with ingredients that are difficult for microbes to digest.
They produce chemicals plant defenses. Some of them are kept in a special storage area of the plant to be moved and used only when needed. Others are in the leaves all the time.
Some are produced as more of a general feeding deterrent and some are quick acting poisons. Hydrogen peroxide is used to counterattack enzymes secreted by certain pathogenic fungi, while other chemicals just kill the fungi directly.
Some of these chemicals become our pharmaceuticals and pesticides. Interestingly, salicylic acid is abundant in many fruits and vegetables when they are grown on healthy, living soil. Aspirin uses a synthetic alternative, acetylsalicylic acid, which causes all kinds of horrible side effects.
I can follow my doctor’s advice and take aspirin every day if I want to experience some of these side effects, or I can eat fruits and vegetables grown on healthy soil.
Plants also employ others to help defend them bacteria, fungi, and even insects. One of the most famous insect examples is the ant-acacia relationship.
Certain species of acacia trees provide homes and food for ants, who in turn protect the trees from insects and even herbivores.
They even prune away other plants that are getting too close. More common to all plants, bacteria and fungi colonize them from head to toe, protecting them in exchange for food.
Different kinds of plants have different survival strategies. Some of them are physical plant defenses.
Some plants, especially annuals, survive by simply growing really fast to get above plant-feeding animals and by producing tens of thousands of seeds per flower.
Longer-lived plants spend more time building strong root systems, difficult-to-digest plant parts and bark, and toxins.
Walnut Leaf Scar
When their branches get injured, they just discard them and grow new ones (I wonder how long it will be until we evolve that skill).
Before they drop them, they make sure to build a strong scar, often with toxic chemicals, so predators can’t get in.
This is one reason in organic gardening why we don’t necessarily want to prune all damaged plant parts, or the leaves and flowers of our perennials that are turning brown after flowering.
Each plant will drop them when it’s ready, after it has recycled nutrients and other substances, and created that scar.
The reason it’s good for us to learn about all of these plant defense mechanisms is because in order to produce strong bark, build strong leaf scars, produce toxins, cooperate with other species, and produce many seeds, plants need healthy organic soil.
Plants are exceptionally good at surviving, if they have the raw materials they need.
Have you ever experienced any of these amazing abilities of plants? The thorns? The toxins? The medicines?