The Biology Behind Plants That Drive Away Common Pests
Use Every Tool at Your Disposal to Keep Pest Animals Out of Your Garden
When it comes to critter-proofing your garden, plants can give you a helping hand. Plants can’t pick up and move when a pest is threatening them. But, they have developed defense mechanisms to protect themselves. You can put this plant weaponry to work for you, especially if you understand the biology behind these plants.
Structural Defenses
The most visible defenses employed by plants are structural, like thorns, spines, prickles. If you’ve ever rescued your dog from a briar patch you know exactly how effective they can be. Bark is another structural defense that protects trees, bushes, and shrubs from many things, including animals.
Other defensive strategies aren’t as obvious, but they’re just as effective. Many plants have chemical compounds they use to protect themselves from attack. Onions and garlic are good examples. They’re members of the allium family. The aromas are natural deterrents to rodents, deer , rabbits, and other outdoor pests. They’re also toxic to some animals , including rabbits (and cats and dogs). Onions and garlic contain compounds called thiosulphates and disulfides. When ingested, they can cause hemolytic anemia. This damages the animal’s red blood cells, making them fragile and even causing them to burst.
Daffodils are another example of pest deterrence through stealthy science. These cheerful yellow or yellow and white flowers are a sure sign of spring. They’re also toxic. Daffodils are members of the amaryllis family. These plants contain a poisonous alkaloid called lycorine. The bulbs have the highest concentration of lycorine, but all parts of daffodil are toxic to animals (including humans). Ingesting them can cause stomach upset, vomiting, and diarrhea. Daffodils don’t stop there. They also defend themselves with microscopic, needle-like crystals known as oxalates. These will burn your lips, mouth, and throat when swallowed. They’re also a skin irritant.
Scent is also a defensive weapon plants use to keep outdoor pests away. Onions and garlic fall into this category. Deer will avoid them like the plague. Marigolds and lavender also emit odors garden pests will avoid. Herbs like rosemary, mint, oregano, and sage smell yummy to humans, but are revolting to rodents. So are spices like black pepper and cayenne. Plant these as borders around your garden or among your edible crops.
Companion Planting
Some plants are especially effective in deterring pests when planted together. Companion planting can help make your garden less attractive to intrusive critters. For example, onions and lettuce are good candidates for companion planting. Rabbits love lettuce but, as mentioned, they’ll steer clear of onions. Mint is a reliable rodent repellent because of its strong aroma. Plant it near rodent favorites like tomatoes or cabbage. Daffodils are a good companion plant for tomatoes. The daffodils will keep deer, rabbits, and rodents away from your salsa and spaghetti sauce staple. Be sure you don’t confuse daffodil bulbs with onions (they look similar). That could be a toxic mistake!
While it isn’t possible to critter-proof your lawn and garden with plants alone, these strategies can help. They’re cheaper and safer for your family, pets, and community than chemical deterrents. So try plant power as part of your pest control strategy. You’ll keep money in your pocket and help the planet at the same time.
Jim Klitch is a botanist who researches eco-friendly pest control. While he enjoys studying the effects of bugs in his gardens, he wastes no time getting rid of rodents which cause the most damage.
Critter Repellent All Natural Animal Repellent Blog
