If you already have fruit trees, or are planning to plant a couple (or a whole orchard), a herbal ley is for you. Similar in some ways to companion planting, a herbal ley features a range of different plants grouped in a beneficial association for the tree.
This is designed to support fruit trees in an orchard, or even surrounding individual fruit trees in a suburban backyard. Sowing or planting a herbal ley is a cunning plan that lets nature do the work for you.
Trees in their natural environment generally don't grow in isolation. They have myriad species of herb, grass, bulb and so on growing around them.
Here, the use of the word "herbal" does not mean herbs in the usual sense, eg, basil, thyme and oregano. "Herb", in this case, refers to "herbage", which is a way to describe leafy green ground cover and low growing plant species.
By planting an array of supportive plants around fruit trees, their health will improve. Most fruit trees do not suit being surrounded by lawn, as many grasses compete with young fruit trees and can suppress the tree's growth.
A good start for healthier fruit trees is to skim off lawn around the tree, then sow "orchard herbal ley" seed. Too much lawn? Use cardboard as a weed mat then put a thick layer of mulch on top of this, which will suppress and eventually kill the grass (avoid piling mulch against the tree trunk). Cut holes through the cardboard and plant your herbal ley species in the soil underneath.
This is how we established comfrey, tansy and lupin around our old lemon tree at the Sustainable Living Centre to replace the grass. A year later, we had bucketloads of fruit.
Alternatives to grass might include clover. This sturdy little groundcover fixes nitrogen from the air and improves soil's nitrogen content, which the tree needs for leafy growth.
Lupins also do this valuable nitrogen-fixing work. They are free fertiliser. Deep-rooted plants such as comfrey are perfect planted around the "drip line" of established fruit trees. Comfrey's long taproot mines the subsoil for nutrients which it takes up into its leaves. As these leaves break down and add organic matter to the topsoil, they contribute vital nutrients such as potassium to the soil, encouraging fruit production. In addition to this, the delicate mauve flowers are an excellent nectar source for bees, as are the flowers of clover and lupin.
Another great group of plants which attracts beneficial insects are those of the Umbelliferous family (now officially titled Apiaceae). I prefer the old scientific name as it describes exactly how these flowers are shaped - like umbrellas, so it's easy to remember. Members of this family include parsley, carrot, parsnip, coriander and dill.
The Biological Husbandry Unit (BHU) at Lincoln University notes that apple trees are very well suited to cow parsley growing as an understorey. This is because cow parsley and other members of this family attract small wasps (safe to humans) which will parasitise and eat leaf roller caterpillars and codling moth larvae - the most dreaded apple pest. There's nothing worse than biting an apple with a grub inside.
Plant Umbelliferous plants around your apple tree, and your chance of a happy apple eating experience is greatly improved.
Plants willing to work
Use a mix of plant families together in a herbal ley.
* To encourage bees and other insects to fruit trees for pollination, and more fruit, plant borage (blue edible flowers), red and white flowering clover, lemon balm, chicory, spring bulbs.
* If you have fruit trees prone to attack from caterpillars and grubs, eg, apple, plant members of the Umbelliferous (Apiaceae) family: parsley, carrot, parsnip, coriander, dill. Let them flower and set seed. Sow again for next year. Apples also suit being planted with yarrow, chamomile, borage, clover, chicory and cornflower.
* For soil fertility and nutrients, plant clover and lupin for nitrogen fixing, comfrey for potassium.
It's not too late to sow or plant a herbal ley if your soil is still moist. For special herbal ley seed mixes check out Kaiwaka Organics or the Koanga Institute. To obtain plant material free, find a friend with comfrey in their garden and chop up the taproot, then plant around the tree. Yarrow, clover, tansy, lemon balm, bulbs and chicory are all easy to divide from an established plant. Plant around your trees.