Companion Planting

In nature a balanced system consists of thousands of diverse plants and animals at work.  When we garden we tend to choose only a few botanical favourites based on scent or colour.  We neglect to choose plants based on their ability to support beneficial insects and organisms.   As a result we throw off the balance, providing pests an opportunity to boom and continue the treadmill approach to pest management.  Consider a long term strategy by choosing plants for the characteristics that encourage insect diversity.  

Companion planting is based on the positive effects plants can share as a method of deterring pests, acquiring nutrients or acting as an attractant for natural predators.  By becoming more diverse with your plantings you are providing habitat, shelter and alternative food source, such as pollen and nectar, something many predators need as part of their diet.

This method of planting is not a 21st century trend but a practice that has been incorporated since the dawn of agriculture.  It has only fallen out of practice in the last 20 years because for a time there was a trend to have immaculate, symmetrical gardens.   During that period much of the gardening lore passed down by generations of grandparents was lost.  Each one of us surely has a story of how Grampa would always place his tomatoes next to the carrots to ward off the Carrot fly or onions next to the roses to prevent black spot.  These tips are not to be dismissed as they come from years of trial and error and observation.


The Pocket Insectary

Trap Crops also fit into the realm of companion planting.  Though the process may go against a traditional gardeners nature you must place your faith in The Bug Lady and understand the logic.  

The concept is to plant a species of plant susceptible to a specific pest to act as a lure for beneficial insects, such as Lupines.  The Lupine aphid (macrosiphum albifrons) is specific to Lupines and will not transfer onto your peppers or cabbage.  The sacrificial plant is allowed to have a colony of aphids establish.  Once the host plant achieves a pest colony the parasitic wasps and predators will also move onto the Lupine as well. Voila, a pocket insectary.  The Lupine provides a source of predators without threatening the intentional crop. By situating the trap plants around gardens which typically suffer from aphids, you are actually protecting your gardens by providing an established security force.

It is important that when you attempt to apply this method using other plants as the trap crop that you confirm the pest species is host specific. Obtain this information through a reliable source.   A search through our links is a good place to start. 

The Following list has been gathered from; Common Sense Pest Control by William and Helga Olkowski and Shiela Daar,  Rodales Encyclopedia of Organic Gardening, Cornell University and Appropriate Technology Transfer for Rural Areas.

Predator Host pests Associated Companion plants
Aphidoletes Aphids Dill, Mustard, Thyme, Sweet clover
Braconid Wasp Armyworm
Codling moth
Gypsy moth
Beetle Larvae
Nectar plants with small flowers.
Caraway, Parsley, Fennel, Mustard,
Clover, Tansy, Yarrow.
Damsel Bugs Aphid, Thrips
Small caterpillars
Sunflower, Goldenrod, Yarrow, Alfalfa
Groundbeetles Slugs, snails
Cabbage maggot
Some small caterpillars
Aamaranth, sweet clover, mulches,
Lacewing Aphids, Thrips,
Mealybug, Scale
Caterpillars, mites
Angelica, Caraway, Dill, Coreopsis
Cosmos, Sunflowers, Dandelion
Minute Pirate Bug
Thrips, Spidermite
Small Caterpillars
Bishops weed, Chevril, Tansy,
Queen Annes Lace, Strawberries,
Carrots, Corn, Hairy Vetch, Daisies,
Nemophila, Coriander
Rove Beetles Aphids, flies, Springtails Rye, Ornamental grasses, mulches
Stethorus Spidermites Carrots, Dill, Fennel, Sweet
Alyssum, Candytuft
Syrphid Fly Aphids Dill, Fennel, Queen Annes Lace
Coriander, Bishops weed, Tansy
Lupines, Scabiosa, California
Lilac,Ceanothus, Sunflowers
Tachinid Fly Cutworms, Tent
Caterpillars, Cabbage
Looper, Sawfly,
Caraway, Bishops weed, Goldenrod
Sweet Alyssum, Parsley, Buckwheat

Trap Crops for Aphids:
Timothy Grass

Trap crops for Thrips:
Shasta Daisy


Ladybug, Ladybird, Ladybeetle
What ever you call them just donít call them late for dinner. If aphids are on the menu you will find them feasting in the garden. If not, you better check out our Buying Bugs section to put them to work.