Good Companions A collection of ideas and information compiled by Graeme EgginsFor centuries companion planting has been a popular technique to combat pests and diseases in fruitand vegetables in Europe. In Australia. the upsurge of public demand for organically grown crops andcorresponding move away from using chemical pesticides and fungicides is seeing a renewed growerinterest in studying the compatibility of plants.In a field trial at the Gatton Research Station, two Queensland Department of primary industryhorticulturists reportedly proved the effectiveness of using dill to control cabbage moth in broccoli. Arow of dill was planted to every 15 rows of broccoli in an experimental block, which was also treatedwith the bacterial insecticide Dipel. The cabbage moth lay was a third of that in a block of broccolitreated conventionally. This trial followed successful companion planting trials using thyme androsemary run by the Victorian Department of Agriculture. Until very recently, companion planting appeared to have attracted little scientific research, possiblybecause it covers so many aspects. A plant may prove an excellent companion to another because itexcretes a substance from its roots or leaves, attracts or repels specific insects by its smell, breaks upthe soil, draws up trace elements from deep underground or offers shade or shelter. A glance over the shelves at libraries and bookshops will show that there is no shortage of advice andguidance for home gardeners. New books come out every year listing what plants grow best withwhat others and what combinations to avoid. However, much of the printed information is based onexperiences in temperate gardens, specially in Britain, and thus has only limited application to sub-tropical areas such as the Richmond/Tweed. (How many local growers want to know that foxglovesare great with apple trees?) Even the published American research has been largely confined to thecooler States of the Union. Also, very little information is known about trials of companion planting ona commercial scale. However, as recent reports indicate, all this is changing. both here and overseas. A number of North Coast growers are experimenting with both herbs or other plants to see if`theycan find new beneficial relationships.Editors note: This article originally mentioned Equisetum (commonly known as horsetail) as a possiblecompanion plant, but Equisetum is a declared noxious weed in NSW and other states of Australia. Dontplant it, and do report it to NSW Agriculture if you find it anywhere in the Tweed Richmond area. Itcould cause significant environmental and economic problems, is toxic to stock, etc. For more info pleasesee the comment at the end of this article.Lemon grass, which originated in South East Asia, is increasingly grown as an inter-row crop inorchards. Not only can it he harvested and sold as a herb (fresh or dried) but it makes an excellentMulch. Lemon grass is also grown in closely planted rows to form a living barrier against intrusiveground covers such as kikuyu.Another popular herb, comfrey, is grown as a living mulch around or close by many vegetablegardens. The hairy comfrey leaves contain valuable trace elements and minerals which have beenbrought up to the surface by its deep-delving roots. Comfrey leaves left to soak in fresh water for afortnight or so make an good fertilizer Fresh, it is recommended as an excellent addition to the diet ofcattle and is reputed to help strengthen the legs of horses. specially those bred for racing. Comfreycan also act as a very effective fire barrier if planted around the foundations of buildings or the vergesof gardens.
Marigolds are deservedly popular and successlul companion plants and the Tagetes variety grow verywell in the sub-tropics. In fact, if positioned too closely to other plants, they can almost overwhelmthem. They are also likely to self-seed wildly, which is not necessarily a bad thing, depending on thesituation.The herbs tansy, basil. garlic, pyrethrum and southernwood have all been tried in North Coastorchards in an attempt to keep fruit fly at bay. However, while possibly helpful, they do not preventfruit fly damage.An occasional clump of horseradish in a shady part of the orchard has been found to help combatfungus problems.Virtually all the common herbs are considered beneficial to North Coast orchards and gardens. Theyhelp attract bees and other beneficial insects while sprays made from the likes of.chives, garlic.hyssop, chamomile, horsetail and elder can be used to combat fungus, mildews and some pests.Incidentally, elders grow like wildfire on most Northern Rivers properties and should never beplanted where they cannot be controlled. Also take care not to drop any prunings - they will take rootalmost before your eyes! Another plant which has proved particularly suited to cultivation in the Australian sub-tropicsalthough no one boasts of it - is hemp (also known as marijuana) which can be used as an effectivecompanion plant for vegetables including potatoes. However, dont expect the police to believe that!To quote the·Encyclopedia of Gardening, published in England in 1824 by J.C. Loudon: "If in a patch ofground where cabbages are to be planted some hemp seeds be sown all around the edge in the spring,the strong smell which that plant gives in vapour, will prevent the butterfly from infesting thecabbages. The Russian peasantry, in those provinces where hemp is cultivated, have their cabbageswithin those fields by which they are free of caterpillars."Seriously, some experimenters suggest planting winter-flowering herbs to attract predators of pestsearly. They are then in position ready to deal with pests that hatch out or migrate in spring. Garlic,pennyroyal and tansy are all suitable companions to orchard crops.Not all organic gardeners believe in companion planting. Queensland author Jeff Hedges wrote inHarvesting the Suburbs published in 1985 that he had reservations: Certainty, sometimes a certain crop doesnt do very well ... but thats my fault for not "tuning in" properly, not the fault of the plants next door! If I plant some crop in a particular spot and it doesnt do well, it means that I didnt select the appropriate crop for that particular place at that particular time.Local TAFE organics lecturer Dave Forrest has suggested that although companion planting can beused with effect in a home garden, farmers found many find difficulty extending it to broadacre use.Of course, not all good growing companions are plants. Small animals and birds are proven colleaguesfor organic growers. For example, a local Permaculture teacher suggests basing a guinea pig at thebase of every fruit tree - it needs to have a weatherproof hutch. These rodents, Whose territorial limitonly extends about 4m from the tree, will keep the grass shorn short. They also attract pythons whoin turn will hopefully - eat rats if they cant catch the little guinea pigs.While guinea pigs may not be practical except in the small home orchard, poultry such as geese andchickens have proved useful in larger establishments: Of all chickens bantams are the best attackersof insects and dont scratch up the soil as much as larger breeds. They also provide good eating andnice, if small, eggs.
Ducks and geese have been used for centuries in orchards, usually being let in for limited periods,normally in autumn and spring. They were also once widely used in the southern states of the USA toweed cotton and similar large crops. Today a number of orchardists in the Richmond Tweed area areusing geese as sustainable mowers.