The Biology Behind Plants That Drive Away Common Pests

Guest Post by Jim Klitch • January 20, 2020

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.

Put the pungency of garlic to good use by spreading chopped cloves around the edge of your garden. This can help drive away rodents. You can also boil chopped garlic cloves in water to make a natural repellent spray.

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.

keep your garden pest free with Shake-Away 100% All Natural animal repellents

Critter Repellent All Natural Animal Repellent Blog

Rabbit
April 25, 2025
As spring rolls in, so does the uptick in rabbit activity. Breeding season, increased feeding, and yard destruction are all part of the spring rabbit surge. Learn how to safeguard your lawn and garden with natural solutions.
Pest activity
March 19, 2025
Learn how to prepare your home for the seasonal surge in pests and keep them from invading your space.
Mouse
February 20, 2025
Mouse infestations can lead to significant health risks and property damage. Learn about common mistakes in mouse control and discover updated strategies for effectively preventing and eliminating these pests from your home.
By Teri Silver February 6, 2025
The last thing you want to see running around your house is a mouse. And where there is one, there are more. Whether it’s mice, ants, spiders, squirrels, or any other type of rodent, bird, or insect infestation, ignoring those critters can get very expensive in the long run. When it comes to remediating or protecting your home from infestations, the cost of doing nothing can lead to a big dent in your wallet. Keeping house pests at bay is important, especially if you’re planning to put the home on the sales market. How much does it cost to keep the house and property pest-free? That depends on where you live, what types of services needed, and how often the home is treated. But one thing is for sure, it’s easier (and more cost-effective) to prevent house damage than to fix everything after critters have chewed up wires, plumbing, foundation, and the yard. Potential Structural Damage Squirrels, moles, voles, rats, and mice are part of nature, but the damage that even one of these critters can do to a home can run into thousands of dollars. With sharp teeth that never stop growing, squirrels and rodents must “file down” their chompers so they don’t interfere with eating and drinking. Thus, a squirrel’s chewing habits can damage house support beams, siding, and anything else that holds the structure up. The costs to repair the building depend on the severity of the damage. Birds’ nests and clogged gutters are signs that unwanted critters are in the building’s drainage system. Replacing damaged gutters can cost several thousand dollars—to start. On average, it’ll cost between $1,600 and $5,200 (depending on size, materials, and labor costs). Wiring and Insulation Chewed-up electrical wiring is not only a hassle but it can be very dangerous. Mice, rats, squirrels, and other critters will gnaw through wires, not knowing that they can electrocute themselves but worse — start a house fire. Homeowners won’t necessarily see exposed wires around the house. Examining the house structure and wiring allows owners to know what to budget for. Pests and vermin living in the attic may tear up insulation to use for nesting materials. Depending on the size of the house, insulation costs can be anywhere from $1,600 to $8,000 on average. Termites When it comes to destructive insects, termites are at the top of the list. These icky little bugs chew through wood almost as quickly as a cartoon buzzsaw. And the worst thing? In general, homeowners’ insurance does NOT cover termite damage. Signs of termite infestation and damage include: Chewed up or hollow wood Blisters or buckling in the flooring Discarded termite wings Bubbling paint Strips of mud tubes along crevices Damaged support beams Tapping sounds in the walls The cost of repairing termite damage can range from a few hundred to a few thousand dollars—or more, depending on what part of the house is torn up and what needs to be done. Preventing termites in the yard and hiring a professional exterminator are two ways of keeping these hungry critters away from your home. Pest Entry Points Cracks and crevices are easy access points for mice, insects, wasps, and other pests. Unscreened vents and windows, loose shingles and siding, and chimney gaps are entry points for bugs and mice. Not having trees and shrubs around the perimeter of the house won’t prevent squirrels and mice from coming onto your property, but keeping greenery away from the structure would deter critters from having direct access to it. Perceived Value Whether your house is currently for sale or it’s a plan for the future, having pests and vermin roaming around the property can keep the buyers away. Among the financial considerations, house-hunting taps the emotions of the would-be buyer. No matter what the item is, perceived value is a customer’s view of whether it is worth the money. An infested home has lost its marketing value, especially if a mouse runs across the floor during the negotiating stage. The cost of doing nothing when you should be doing something can lead to a huge repair bill and maybe even a home improvement loan or second mortgage on your house. Ignoring the problems won’t make them go away. If wildlife and insects are damaging your home, do something about it sooner than later.
Pest-Proof Insulation
January 18, 2025
Pest-proof insulation is a game-changing solution for homeowners looking to prevent unwanted intrusions and lower energy costs. Learn how this innovative product protects your property from pests while boosting energy efficiency.
Home Maintenance
January 9, 2025
Proper home and business maintenance is the first step in preventing pest infestations. Learn how regular upkeep, repairs, and preventive measures can keep pests out and ensure your property remains safe, clean, and pest-free.
Green Pest Control
December 10, 2024
Discover the latest eco-friendly technologies and treatments revolutionizing pest control. From organic solutions to advanced traps, learn how innovative methods reduce pest problems while prioritizing environmental health.
Pest Control Issues
November 27, 2024
Apartment buildings are especially vulnerable to pest infestations due to shared spaces and frequent tenant turnover. Learn about the top pest issues in apartment complexes and how management can implement preventative measures to keep them under control.
Pest Invasion
November 25, 2024
Unseasonably warm weather drives pests like rodents, insects, and other invaders into homes earlier than expected. Learn how the changing climate affects pest behavior and discover effective ways to protect your home from infestations.
Woodchuck
October 21, 2024
Woodchucks, known as groundhogs, can destroy gardens and yards. Learn about their habits, diet, and the most effective methods for keeping them off your property to protect your landscape.
More Posts