These few hints are mainly for the backyard fruit tree enthusiast for two reasons:

(1) I would feel somewhat cheeky and presumptuous trying to give advice to experienced orchardists whose knowledge and expertise would dwarf mine in most instances.

(2) These suggestions would be difficult and impracticable on a large scale.

Firstly, use mulch in a specific manner. Probably everyone who likes gardening, and especially those who grow shrubs and trees, realise the importance of mulch. This approach is to enhance the value of mulch in a time-saving, more efficient way.

Host fruit trees have no objection, in fact enjoy, mature filter press. So the first thing I do with a young tree is to put a good size mound, say a metre across, within reach of the tree's root system. With a small tree, leave about 30cm (one foot) between the trunk and the mound. As the tree grows on, you can gradually build the mound further away from the tree, removing the inner border as the tree gets bigger and bigger.

To this mill mud mound, I add successive layers of grass cuttings from the catcher each time I mow. This mound gradually becomes a haven for an immensely rich variety of insects, worms and micro-organisms, which is the sort of micro-environment which trees just love and need. With few exceptions, trees don't like being just stuck out in the open surrounded by nothing but mowed lawn. This is nothing like the tree's natural environment which we need to try and approximate to get the best results.

The mound method is particularly effective during the most stressful time of the year, that is, before the wet season when we can have prolonged, very hot, dry weather. Bearing in mind that the size of the mound depends on the size of the tree, then one can use that mound to cut down on the amount of water used for each tree, also the frequency of watering. Ten litres of water (with dissolved plant food when required) poured slowly down through the centre of the mound would keep the base moist for possibly a fortnight, no matter how hot it gets. However, I water once a week in the hot dry weather to play safe.

One interesting fact I discovered this year to do with fruiting trees, in this case the grumichama, was that just trickle-soaking in the one place is not good enough for a tree laden with fruit. At such a time the tree needs virtually all its root system soaked, in other words, use a sprinkler. Just watering down through the mound is not good enough at fruit time.

However, for the rest of the year, compare this mound method to sprinkling open ground when one has to use a lot more water to saturate the soil. Then the sun and wind evaporate a lot of it and you have to water again in a couple of days. Also, you are encouraging the growth of weeds where they are a nuisance. True, the mound itself is a wonderful spot around the edges for grass and weeds to grow, but they are easily removed and added to your mulch on the heap. Actually the grass border can be used as a containing wall and can be kept relatively short for neatness.

Something else I find the young tree seems to appreciate is this - in their natural state in whatever country of origin, these tropical exotic seedlings would not, in most cases, be growing in a relatively bare patch of ground. The natural state would be more likely the young tree being sheltered by the parent tree and for other trees, with a bed of natural leaf mulch or litter surrounding it, protecting it from excessive soil and air temperatures and moisture loss.

To this end I like to put a small bird-wire mesh 'fence' in a full circle around the trunk of a small tree. It doesn't have to be any more than 6 inches (15cm) high unless it serves the dual purpose of keeping leaves in and animals out. This enclosure then is for keeping the ground within completely covered with leaves, which unlike grass, does not predispose the stem or trunk to fungal attack, provided one does not make the collection of leaves a foot deep! This technique helps prevent grass and weed growth around the trunk, preserves moisture and supplements the soil generally. By the way, some leaves are more suitable, being more durable than others. Avocado and mango leaves are good. Speaking of avocado, I have no scientific proof but I think the rich mill mud mound with its myriad of beneficial organisms acts against the phytophthora fungus which is the enemy of avocados in particular.

My backyard has nowhere near the amount of grass to be mowed than before the trees were established. I have these micro-environments of mounds and mulch around most of the trees, while the big trees have established their own leaf litter environment beneath, where suitable. The mound becomes less important for the big trees.

I think the evidence of how good my trees look during the most stressful time of the year, is humble testimony to the effectiveness of the above techniques in keeping trees happy.

Barry Scurragh

DATE: March 1992

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