Underplanting Orchards
December 06, 2021
THE ‘UNDER STORY’ ... A CASCADE OF COLOUR AND A CHANNEL FOR CARBON: BRINGING SOIL TO LIFE WITH FLOWERS.
Christine Jones, PhD, Founder of Amazing Carbon www.amazingcarbon.com 
An extraordinary soil health revolution is taking place across the world. Innovative farmers experimenting with poly culture through intercropping, interseeding, companion cropping, planting green, relay cropping and the use of multi-species covers and forages are achieving improved levels of soil carbon, nitrogen and phosphorus, increased availability of trace elements and enhanced aggregate stability, porosity, infiltration and soil water-holding capacity.
Not that polyculture is anything new. People have produced food within diverse plant communities for thousands of years. It’s just that until recently we forgot how!! (Polyculture is the practice of farming where there is more than one species grown in the same time and place. The opposite of monoculture.)
Soil is a living ecosystem. It contains more species than any other ecosystem on earth. Most soil life is microscopic - that is, too small to see with the naked eye. But we ignore it at our peril. It is life that gives soil its function.
Plants obtain the genetic material they require (for nutritional purposes, resilience to abiotic stress and immunity to pests and diseases) by cultivating then internalising soil microbes. Microbes taken in through plant roots are incorporated into stems, leaves, flowers, fruits and seeds.
Every kind of plant supports a different suite of microbes. Optimal plant function is achieved through ‘root mingling’ in the sociobiome created by many different kinds of plants growing in close proximity. This diversity of genetic material enables plant communities to thrive, even under less than ideal conditions.
Historical context
At the time of European settlement much of what is now Victoria supported an amazingly diverse groundcover of flowering plants. The high water-holding capacity of the soil was the result of active microbial communities forming well-structured soils that remained hydrated, even during hot, dry summers.
Numerous historical records refer to 'fields of flowers' which sadly no longer exist. Tubers of groundcover plants such as yam daisy (Microseris lanceolata) and a wide diversity of lilies and terrestrial orchids provided a staple carbohydrate source of fundamental significance to Aboriginal people.
The food plants most prized by indigenous communities were also the most keenly sought by livestock. Within only a few years of unmanaged grazing, the abundance of many flowers declined from common and widespread, to rare or locally extinct.
Only the least palatable components of the original groundcover survived. These were the grasses. It is now common to see trees with an understorey of grass - but that does not mean a combination of trees and grass is natural - or beneficial. Grasses are very competitive with trees. Fortunately there are other plants that are good companions.
Plant diversity in horticultural systems
The restoration of plant diversity is proving to be a ‘miracle cure’ for many of the challenges facing horticulture. A classic example is the reversal of Citrus Greening, a theoretically incurable bacterial infection that has devastated the $9 billion Florida citrus industry. A wide range of measures, including the use of insecticides, antibiotics and genetic engineering, have failed to curb the disease.
Ed James, an innovative citrus grower, resolved the problem by planting a 12-way mix of legumes, brassicas, cereals and flowers in the inter-rows of his citrus grove. Scientists are currently following up on Ed’s success and assisting other growers adopt similar techniques.
Diversity in the backyard
Fortunately for home gardeners, a wide range of herbs and flowers can be grown under fruit trees. Although most plants will not grow as well in shade as they would in full sun, they will grow. Remember, you’re doing this for the benefit of the tree.
Mulch is infinitely better than grasses or bare ground, but mulch alone does not support sufficient microbial diversity for optimal tree health. Your trees will still be socially isolated.
Beautiful and beneficial for insects, Borage makes for a great companion plant.
Companions for fruit trees include asparagus, borage, basil, dill, chicory, chamomile, lemon balm, oregano, marjoram, chervil, bee balm, coriander, fennel, parsnip, phacelia, yarrow, lupins, parsley, sage, rosemary, thyme and plants in the allium family (such as garlic and chives), Flowering herbs are excellent attractants for bees and other beneficial insects and as a bonus add zest to salads.
Edible flowers such as viola, pansies, nigella, alyssum, nasturtium, cornflowers, chrysanthemum, marigolds, zinnias, cosmos, day lilies, gladioli, carnations, echinacea and calendula can also bring life to tree understoreys and feed the soil as well as the family. Aim for as much plant diversity as possible. You could even throw in a few strawberries. Tastier than grass!!
A word of warning if you intend to eat the flowers - make sure you know for certain what they are, as some flowers are poisonous. Once introduced, many herbs and flowers will propagate themselves by self-seeding from one year to the next
Biostimulants such as vermiliquid (liquid from worm farms), compost extract, seaweed extract and fish hydrolysate are beneficial when establishing your understorey plants. Best results are obtained by combining two or three different biostimulants at one half to one-third the recommended rate. Autoinducers in biostimulants signal to the seed's core microbiome and help seedlings interact with resident soil microbes, which in turn are taken in through the roots (biological induction) and live within the plant for the remainder of its life. Some of the resident microbes are encapsulated within the next generation of seeds and emerge into the soil when those seeds germinate.
In healthy biological systems seed vigour increases over time, which is a very good reason for farmers and gardeners to keep their own seeds. The transfer of the plant's core microbiome from one generation to the next is termed vertical transmission. It works in reverse when high-analysis fertilisers, insecticides or fungicides are applied to seeds. Then we see a downwards epigenetic spiral. Switching from toxic chemicals to biostimulants is not a difficult change to make.
Once your backyard or orchard becomes a floristically diverse, microbially interconnected ecosystem, it will be highly productive as well as producing healthier and more flavourful fruit and vegetables.
Flowers are not a nice afterthought … they are an essential ingredient. A feast for the eyes and a feast for the soil.
May flowers always line your path and sunshine light your day may songbirds serenade you every step along the way
~ Irish blessing ~
