By Briscoe White

Nobody likes to be bugged, or appreciates a pest.  However, when the annoyance is of the insect variety, dislike can quickly progress to hatred.  When being plagued by insect guests, any solution, up to and including an all out war on anything with over four legs, seems entirely reasonable.  Poisons quickly transform from an extreme measure to a viable solution.

The balance between needing to protect your plants and trying to find an environmentally friendly solution presents a dilemma every gardener must eventually face.  What is often forgotten is that the battle between insects and humans has existed as long as we have, and historically the war was fought without the chemical aids we now have at our disposal.  In general, most people are also unaware of the ongoing, and long running, battle between the plant kingdom and insects. Viewed over a longer evolutionary timescale, plants have evolved with insects, and have adapted with far more successful natural defenses than humans have been able to come up with.

As organic and sustainable practices have morphed from a fringe movement to commonly accepted best practices, a renewed interest has emerged in using plants as a natural insect deterrent.  Traditional practices, such as employing companion plants to protect gardens, have remerged as potential solutions, but many remain skeptical as to how effective these tactics can be.

How Pest Deterrence Works

Unlike the recent introduction of man made chemicals, plants and insects have coevolved.  That means the same chemicals that make herbs and certain fruits tasty additions to our favorite dishes initially developed as an attempt to proactively discourage natural enemies from chomping down on tender leaves and seeds.  The chemical compounds plants generate are intended as self-defense, and are usually targeted towards a pest found in their native region.  For that reason, using plants is like using a heat-seeking missile compared to the nuclear bomb of broad-spectrum insecticide.  As such, herbal defense should strategically be selected to address the particular issues your garden is facing.

Determine What Pests Affect Your Garden

Common sense dictates that pests differ from region to region.  What gardeners often don’t consider is how the plants they choose affect what kind of infestations their garden may experience.

As a first step, find out what zone your garden falls into and what insects like to live there.  Second, consider the types of plants you’re using.  From sedums to succulents, plant varieties are subject to particular attacks that should be considered when planning your defense.  Finally, keep in mind that the location of your garden will play a key role in what insect attacks you will face.  At a small scale, soil, humidity, elevation, and many other factors can influence what types of pests you may face.  On a larger scale, human habitation and land coverage can significantly impact what insects are found in a particular region.  When you’ve finally determined what insect armies are trying to invade your garden, you should then establish the corresponding approach to block their advance, and how to arrange your herbal defense.

How to plant

If you are considering herbs as a natural defense against insects, your decision should be made before you lay out your garden.  Defense herbs should outline the periphery of your garden, and be concentrated around your most vulnerable plants.  In many cases, leaving room for a companion plant can be an important part of your strategy.  Companion plants include plant types that draw beneficial insects to your garden, insects that will often prey on the pests you don’t want to infest your garden, as well as plants whose scent is a deterrent.   In instances when beneficial insects are particularly desired, companion plants offer an ideal solution, as any herbal remedy that includes spraying or treating with plant oils will cause casualties among your beneficial insect population.

Uses After Planting

While planting herbs in your garden can provide an excellent first line defense against insect infestations, herbal plants can also provide significant secondary defenses through processing their leaves and oils.  As mentioned before, particular classes of herbs are identified with specific insect families, and the plants and sprays created from their treatment.  For example:

• Thyme discourages cabbage worms
• Wormwood keeps snails at bay
• Rue protects from Japanese beetle attacks

Pesticide companies are making a killing with the recent interest in “green” products, and it’s not hard to find organic or sustainable products.  What the manufacturer doesn’t tell you is that organic products can be just as damaging for the environment as manmade ones.  Instead, create your own treatments by using 4-5 parts water, a tablespoon of cornstarch and one to two parts herbs.  Although harder to process, most herbs can also be pressed to produce highly aromatic oils that are more effective at persuading insects they don’t want to enter your garden.

Conclusion

Just like most things worth doing, building an herbal defense plan for your garden is hard work, and takes time and dedication. There’s no small amount of forethought, planning, and strategy that must take place for it to work. But at the end of the day, or season, it’s worth it. You’ll be able to proudly boast a completely natural garden, and, to top it off, you’ll have a number of plants that you might not have grown otherwise. Employing a natural insecticide strategy is just one more way to have fun growing the size of your garden while staying in close touch with nature.

About The Author

Briscoe White is owner and master grower at The Growers Exchange, an all-natural online garden center that specializes in rare and traditional herbs for culinary, aromatic and medicinal use. He has been in business for over twenty years, but his love of nature and gardening date back ever since he can remember. Member of many garden and nature-related organizations including the Garden Writers Association, when not tending his greenhouse or writing for his blog, Briscoe’s Seeds For Thought, he spends what little free time he has planning his next garden and playing with his dogs on his family farm in Charles City, Virginia.