Herbal First Aid - The Garden

With over 250,000 new chemicals produced each year, we still have no idea of their side effects. Tests have shown some pesticides to be so toxic that they have had to be withdrawn. Yet there are still 3 million acute pesticide poisonings each year worldwide. Health authorities document the problems arising from herbal medicines and supplements yet few real clinical trials are carried out to determine the safety of over 100,000 foreign chemicals that are released into the environment annually.

Companion planting can help reduce our reliance on spraying with chemicals when things go wrong in the garden, and how it works can be seen in three stages:

Herb Resistance

Herbs are quite resistant to attack by insects and disease.

Due to their particular active constituents we use herbs medicinally and to bring zest to food.

Often these active components are specifically produced by the herbs for their own defence.

Different families of herbs evolved with their own main active defence constituents:

The Compositae or daisy family mainly use bitter-tasting sequiterpene lactones to deter insect attack. Many Umbelliferae or parsley family members contain phototoxic furnanocoumarins that can be vulnerable to sunlight. The Labaitae or mint family notably have large amounts of monoterpene oils in their leaves and some of these can deter or prevent insect or slug attack.

Specialist Exploiters

These family defence systems work against a wide range of attackers, but a small number of attacking species overcome the plant’s defence to become specialists that can exploit the plant with little competition.

Companion Planting

The stage is now set for the concept of companion planting:

Some herbs have roots which produce protective secretions.

Others have leaves containing large amounts of volatile oils which will evaporate on warm days. These volatile oils form a mantle around a herb in still air that can prove a barrier to some attackers, eg, the thujone in sage and wormwood can deter insects and caterpillars.

This protective vapour mantle can give protection to adjacent plants.

Specialist insects that selectively exploit one family of plants, may be deterred by an adjacent companion plant family’s defence system.

CHIVES (Allium schoenoprasum )	Planted near roses chives will help to repel aphids. Grow near apple trees to prevent scab, chives have a fungicide effect which protects against black spot and mildew. Special Note: Allow chives to flower then cut and lay them on the ground between strawberry plants to deter fungi. Chives are beneficial throughout the garden, but do not plant next to peas and beans
WHITE HOREHOUND (Marrubium vulgare)	Bees love the musky aromatic scent given off by the horehound flowers Grow amongst tomatoes as it is a good fly repellant. Special Note : Dried and fresh horehound leaves can be infused in milk in a shallow container and then placed in a fly infested area to deter them.
LEMON BALM (Melissa officinalis)	Outstandingly attractive to bees so plant where bees are needed to pollinate other flowers. Makes a good liquid manure when steeped in rainwater and allowed to decompose, in much the same way as comfrey. Special Note: Take a handful of chopped leaves and make an infusion in boiling water, allow to cool and soak area around plants infected with red spider mite.
MARIGOLD (Calendula officinalis)	Plant marigolds next to the tomatoes to combat whitefly, also enables plants to grow better. Helps to repel beetles and discourage eelworms when planted amongst flowers and vegetables. Special Note: French Marigolds (Targetes patula) give off via their roots a substance which kills soil nematode worms in rose beds. To be effective it must be grown for more than one season.
NASTURTIUM (Tropaeolum majus)	Repels whitefly, woolly aphids and ants. Plant under fruit trees as a trap for pests. Attracts blackfly to itself and away from vegetables, so use it as a sacrificial plant. Special Note: Nasturtiums will repel a wide range of harmful insects and make an excellent companion plant when planted in between rows of vegetables to keep pests, such as blackfly away from cabbages and broad beans.
TANSY (Achillea millefolium)	Discourages beetles, ants and flies, planted near fruit trees it can help to deter fruit moths. Sprinkle dried, crushed leaves to get rid of ants. Special Note: Dried tansy mixed with dried elder leaves and placed in a bowl around the house is of great benefit to people who are asthmatic or allergy prone and who cannot tolerate commercial insect sprays.
BENEFICIAL INSECTS :	To attract beneficial insects such as bees, lacewings and ladybirds to your garden plant: nasturtiums, lavenders, chamomile and scented geraniums. Plant members of the daisy family and a variety of herbs including sage, thyme, dill, fennel and mint are ideal for drawing beneficial insects in, allow the herbs to flower to draw in a large number of garden friends.

The information above was compiled from information sheets that were drawn up for sale by the Herb Society at the 2002 Chelsea Flower Show. We've added some photos of the herbs to the fact sheet for ease of identification and a little additional information.

Herbs In Medicine

Herbal First Aid - The Garden

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