Merv Cooper is a longstanding, highly active member of the Club. He describes himself as a ‘pomologist’ – what is that, you may ask? Well, one dictionary definition is “the science of fruit growing”. This is highly apt description of Merv, who takes a very scientific approach to his fruit tree growing, particularly in the area of selectively breeding feijoas.
Merv and his wife Sybil live at Loganlea on a block of about 1 acre, where they have been for about 10 years. Roughly half of their block is devoted to fruit tree growing, with the rest being landscaped with attractive ornamentals. The soil is fairly acidic clay, which Merv treats with lime and dolomite. The orchard’s water supply is from rain-water, gravity fed to drippers, and a bore which can run sprinklers. A feature of the garden is the heavy use of mulch in the form of wood chips. Merv makes quite lot of this mulch himself, using his own chipper. The orchard is completely mulched between trees, with no competition from grass or weeds. Part of the reason for this approach is Merv’s philosophy of ‘minimalist watering’. He reasons that fruit trees should be tough and able to cope largely on their own, although he does water his young trees, and occasionally the larger ones, if they show signs of stress.
One of his water-saving devices is to use 25 litre plastic containers, with a short piece of 13mm poly pipe inserted were the tap inlet is, with a dripper on the end of the pipe. He places these next to trees that require water, and fills the container with a hose every day. The dripper lets the water run slowly out, taking from 12 – 24 hours to empty the container, and thus giving the trees a very slow and deep watering. Merv’s scientific approach is illustrated by the experiment he conducted using these containers. He used his watering method on several trees over a long period, and then dug down next to the roots to see how far they had gone down into the soil, compared with other trees planted at the same time. The slow drip method gave better results, even with citrus, which are considered to be shallow rooted, showing deeper penetration of the roots into the soil, and thus a better ability to cope with heat stress or lack of water.
Merv takes a proactive approach to orchard management, using techniques such as heavy pruning every year in late autumn, and the regular use of boron and potash, in addition to fertilisers like Nitrophoska, superphosphate, and chicken manure pellets. Boron is used every year, in the form of borax at the rate of 1gm per litre, sprayed on at early flowering stage. Merv says this helps fruit set, particularly with custard apples. He also swears by the use of potash, giving his trees a dose once a year. This is applied at about the rate of a 1.5 litre container (for a largish tree) of sulphate of potash spread widely, but Merv says the quantities are not too important, as you can’t really give them too much. He keeps a hive of native bees, which help in pollination.
Pest management is also important to Merv, and he uses several techniques in combination. Fruit fly are controlled with a male attractant and protein spray to knock out females. Cloth bands tied around the trunks of trees (especially citrus) are soaked in chlorpyrifos, which prevents ants from climbing up the tree, and thus controls aphid and scale (chlorpyrifos is available as a commercial product such as Pidgeon’s Pest Controller). Merv monitors pests carefully and if he does have any problem, tries to identify the culprit under his high-powered microscope.
The trees in Merv’s collection are too numerous to list – he has just about everything you could think of! Amongst the more usual citrus, stone fruits, tropical apples, pears, mangos and bananas are some special features, such as a number of members of the Annona family (including Poshte, Cherimoya, Soncoya and Atemoya), and three types of Grumichamas - yellow, black and white. Some edible natives are the Midyim Berry and the delicious Aniseed Myrtle (Backhousia Anisata). There is an unusual ‘orange raspberry’ from Papua New Guinea, and a large Guasaro tree, both of which he says have really tasty fruits. Other items of interest are a sweet Tamarind which keeps longer and tastes better than the regular variety, and the White Sapote ‘Chris’, which is a very good variety.
In a special section of the garden, Merv is testing his theory that you can interplant species requiring different levels of soil pH, by only treating the immediate root area of the tree, to alter pH as required for each species. He defines the area to be treated by placing sleepers in a square around some of the trees. He has planted in close proximity, a number of trees including Longan, Olive, Governor’s Plum, Blueberry and Rollinia, and believes that the roots of each will avoid the areas where soil pH is not suitable for them.
Merv’s really special interest, though, is selectively breeding Feijoas in the pursuit of a really good variety suited to the sub tropics. He has had a long interest in Feijoas, stemming from his background in the biological sciences for 30 years, working in the administrative and business side of plant development and pest management. In New Zealand, he was involved in obtaining plant variety rights for two varieties of Feijoa (Apollo & Gemini) and their subsequent commercialisation. When he moved to Australia, however, he found there was little in the way of industry support for Feijoa growing, and that the varieties available were very inferior. Inferior seedling trees have been marketed in Australia, giving the species a bad name in terms of taste, whereas the superior selections are actually very good.
Merv explained that the Feijoa grows naturally in only a very limited area on the borders of Uruguay and Brazil in South America. It was first described by a German botanist named Sellow in the 19th century, hence its latin name Acca Sellowiana. These trees produce a very poor fruit that is not worth eating but an infusion of the leaves was used by the indigenous people of the area to treat dysentery and cholera. One specimen was transported to Europe in the late 1800’s and it is widely believed that all varieties that are currently available originated from this one plant.
The plant prefers acidic soils (pH ~ 6.0), a sub-tropical to temperate climate and is mainly pollinated by birds such as honeyeaters, rather than bees. They are currently grown mainly in Italy, USA and New Zealand where several good varieties have been developed. Australia has never really had a good breeding program for selection and commercial development of the feijoa.
Merv is one of the few people that not only loves growing interesting and rare fruits but has taken this interest one step further. He has been actively trying to develop new and improved Feijoa varieties suited to sub-tropical climates for some years now. His efforts started when he imported seeds derived from about ten named overseas varieties. He collected seed from two different international locations in order to get as great a genetic variation as possible. From these seeds he propagated 600 seedlings. The best 200 of these (selected for superior disease resistance, tolerance to drought and many other criteria) were planted out in his garden and allowed to grow to fruit bearing size.
The best of these (selected on the basis of disease resistance, overall tree shape, flavour and size of fruit) were cross pollinated with each other. This process involves bagging the flowers and only allowing pollen from selected varieties to pollinate the fruit. This provided seeds for a second generation of Feijoas from which he obtained some eighty plants from which he has obtained four distinct selections which possess the desired characteristics. The cross pollination process has been repeated to give a third generation of Feijoas seedlings that are currently still in pots. Overall this breeding program has taken about ten years and Merv believes that with luck and a little more time he could develop a new Australian variety.
Merv emphasised that Feijoa fruits have to be fully mature for good taste. The fruit is mature if you can place your hand underneath it and gently lift the fruit. If it easily detaches from the stem it is ready, and should not be picked before this stage as it does not ripen well off the tree. The fruit can keep up to 2 weeks, perferably in the fridge.
The scientific approach taken by Merv to his fruit tree growing has led him to collect a large quantity of books and notes about feijoas, native bees, and fruit tree growing topics generally. He is happy to share these resources with others if they have an interest, as he believes in sharing information freely. Give the pomologist a call if you want to know more about these topics!