Flood Damaged Gardens By Pam Thoday, Wartook, Vic.
Many of us have had our gardens saturated by water in the past few months, Pam has some advice for remediating the soil and saving the plants. There has been unpredictable weather in many parts of Australia over the past 12 months, with some areas still being impacted by flood waters. While many of us were lucky enough not to be under a metre of water or more, we have still been left with gardens damaged by waterlogging and soil compaction. As you will have noticed, some plants have a higher tolerance to waterlogged soils than others. Desert and Mediterranean plants tend not to cope. In most cases the standing water causes their hair roots to rot away, and the impact is noticed when hot weather starts and the plant simply can’t take up water through those roots. Some trees can continue to function for months on stored water and nutrient, but will ultimately die. It is heartbreaking! Many people I’m in contact with have lost cherry, apricot and plum trees, while some remaining trees are easily stressed by heat, indicating that they have insufficient hair roots. It may help to prune back stressed trees to reduce the transpiration or loss of water through leaves. Yates sells an anti-rot product that may also assist when sprayed on foliage. We hoped that some plants would reshoot; a kiwi fruit vine is struggling back, but most were dead when we cut them back or dug them out. What to do
Review your needs and replant if required. I prefer to buy bare-rooted fruit trees as I can see their root development and they seem to transplant better. We will be making some mounds in the orchard, adding plenty of loam and compost and planting new cherry trees about
20cm above natural ground level. While their roots will still penetrate the natural soil, a mat of hair roots should sit above the water table despite waterlogging. When preparing the soil to replant, either dig out the stump or cut at ground level and replant nearby and leave the wood to rot, then make sure to dig over the area to at least two spade depths. If the ground smells anaerobic, or like sulphur, leave it to be exposed to UV light and turn a few times to kill bacteria. If not, or after a week, add new soil, compost and potting mix to raise the level. In winter, plant into your mounds, making sure any graft unions are well clear of soil level. I recommend mulching well and ensuring that these new trees receive ample water, such as drip irrigation, over that first summer as they will be at a higher risk of drying out. When G R A S S
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adding mulch keep an area clear of the lower bark to discourage root rot. We cut the top and bottom from large 4lt olive oil tins and cut along one side. This wraps around the trunk leaving a gap and can be removed when the tree has grown. For existing damaged trees, consider digging swales above them to direct water around the main root area. We are planning some largescale earthworks to channel water away from the orchard area in wet winters, with sluice gates that can be added to retain summer rainfall. Oh the joys of future proofing and its constant modifications! Seaweed emulsion will also assist roots to build immunity to root rot. In the ornamental garden we removed many dead plants, cutting back those with dead centres in the hope that they will reshoot and bush out. Fortunately we had already propagated many new plants from
