HOW TO. Planting techniques for helping plants cope with extreme conditions

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1 HOW TO SURVIVE THE DROUGHT The Mediterranean Beach Garden at Royal Botanical Gardens, Kew. Image copyright East of Eden Plants Planting techniques for helping plants cope with extreme conditions Despite the recent washout summers, as predicted, the trend in the UK over the last 5 years has been towards more drought conditions. East Anglia was officially declared a drought area (June 2011) with more regions at risk. England and Wales had their driest March in more than 50 years with some parts having less than 2mm: less than is normally recorded in the Sahara desert at this time of year. Gardeners, be warned. Read more. Centre for Ecology and Hydrology For a number of years East of Eden has been involved in the creation of lush outdoor plantscapes that continue to flourish even in extreme water shortages, in light of the ever increasing drought conditions. A driving force for our director and chief designer Peter Belton has been his passion and obsession with inspirational gardens found in very dry and hot areas of the world, from the Mediterranean to the deserts of California and Mexico.

2 Combined with his academic and research background in world ecosystems, Peter has applied his theoretical understanding to his design and practical experience enabling him to develop and establish some fundamental principles and techniques that East of Eden have used in the creation of lush outdoor spaces designed to endure times of drought. Our expertise in this area was recognised 4 years ago when we were approached by the Royal Botanic Gardens at Kew to help create a 60 metre coastal Mediterranean theme. The image above is of the Garden.

3 One of our developments in 2011 is supplying and supporting the Environmental Landscapes Consortium (ELC) of Malta. ELC is the public-private partnership organisation responsible for Malta s high standard of civic planting, a programme which produces over one million plants each year. ELC are currently planting mature trees at the capital, Valletta, trialling Rootgrow mycorrhizae provided with our guidance, to help the trees establish earlier, overcome planting shock and as an additional drought buffer to Malta s long hot summers. Malta also hosted the conference of ELCA, (European Landscape Contractors Association). Read more

4 Benefit from our experience to help beat the drought Our developed techniques meet the changing climate in Britain head-on, drawing on evidence and experience from parts of the world already habitually dry. Dry countries already cater for drought. Our proven methods can be adopted by landscapers and gardeners undertaking drought buffering projects as a new experience. There are 4 principles that we apply to all of our projects, from extensive landscapes to small courtyard and terrace or roof gardens. 1. Selecting drought tolerant plants 2. Preparing the soil for water retention with good drainage 3. Applying beneficial fungi (Rootgrow) to the soil or compost or directly to plant roots. 4. Using water wisely by : installing using self watering tanks and water absorbing granules applying water directly to the plant roots using simple direct root self watering irrigation systems

5 1 Selecting Drought Tolerant Plants Careful selection of drought tolerant plants was used for our Kew Mediterranean Coastal Garden project Many world plants are already adapted to coping with drought, and some of these are already garden favourites. Our extreme plant list extends the range to include proven species you may not yet have considered. Drought tolerant plants are plants that can sustain significant periods of drought without suffering undue harm. However, even drought tolerant plants will need watering after planting until their root systems become fully established. Drought resistant plants often have grey-green, or silver leaves that help to reflect the sun and sometimes have fine hairs helping them to trap moisture close to the plant.

6 2 Preparing the soil for water retention with good drainage As well as managing projects for drought buffering, we also design large scale projects for flood prevention. Often, they are the same project! That s the UK for you. Too much water and too little? How do we square this circle? The UK s climate is moving towards long periods of reduced rainfall interspersed with periods of sudden torrential downpours, as is already witnessed. Plants, like all life, live within a range of conditions, a comfort zone, in which they do well. Water is the most essential element to all life. Different plants have evolved to cope with different climate zones. When a climate zone changes and the available rainwater diminishes, the plants that grow there are under threat. Either the climate zone has to be managed (irrigation, drainage, mulching, greenhouses) or the plants have to be exchanged for drought tolerant plants. Our approach is to use drought tolerant plants, draining the excess rainfall when present, while building in targeted water retention systems at the point of need. This approach draws on industry best practice combined with our own practiced expertise and is scalable from large projects right down to the home gardener. Getting the soil right Rainfall is only one half of the water supply equation. Where does that water go? How is it stored in the ground for plants? The study of different soil types and the ability of water to move through it is studied by the science known as Hydrology. (See References for links to more information.) Fortunately for us at East of Eden, plantscaping is often landscaping that is part of the built environment, which means we develop and supply our own specific soil structure to meet the needs of the plants. Where we work with the natural local soil conditions we can make improvements to support a wider range of conditions than normal soil. Using drought tolerant plants requires specific soil types. Extreme conditions call for extreme measures. Our knowledge of soils lets excess water escape and then retains vital amounts. We use careful amounts of water retention granules in the mix to store water.

7 Planter Size We have developed our own range of large planters for use in place of ground soil alteration; these are in addition to our ranges of self-watering planters and selfwatering systems to fit existing planters. Planter size is crucial to success and it is important to use planters with a capacity greater than the plant s requirement. With round planters, for example, increasing the diameter by a few centimetres will double the volume. Generally, the larger the planter in relation to the plants, the easier it is to create the right environment with sufficient water retention capacity. For substantial plants we make our own range of long lasting decorative wooden planters in oak and European redwood. Our troughs have a standard length of 1.8 metres and are extra deep, but can also be built in custom sizes to fit specific projects. Customers can order a complete installation or we can supply the troughs and planters separately. We also use and supply other planters, including decorative terracotta finishes in sizes up to one metre diameter, as well as other materials, to fit specific requirements.

8 3 How your plants can survive the Drought with Rootgrow Establishing the role of mycorrhizal fungi in the active growing region of soils, the rhizosphere, has been a modern scientific achievement. Isolating the mycorrhizae for use in planting applications is a British success, Rootgrow. This innovation means we can now make use of Nature s own defence against drought. How do plants manage to grow quite happily in deserts and arid environments throughout the world? Is there something that can be learnt from studying plants in these environments? This research has been going on for decades and there is a great deal known about drought survival mechanisms. One of the most important involves an entire group of friendly fungi called mycorrhizal fungi that live on the roots of virtually every plant on the planet. Rootgrow contains mycorrhizal fungi species some of which are specifically adapted to water stress conditions. Applying these fungi at planting time will ensure that your plants will get the best chance of survival. These beneficial mechanisms are the reason why plants can grow in semi-arid ecosystems and agriculture. We must start to utilise this beneficial role of the fungi if we believe water shortages are here for the foreseeable future. East of Eden have been using and supplying this solution with Rootgrow since Application Rootgrow from East of Eden on a Maltese project tree Note the use of the Tree Irrigation Tubes at this stage. With many gardeners and growers prevented from using hose pipes, the traditional gardening methods of using high inputs of water and chemical fertilizer will not work since the nutrients do not have water in which to move in the soil towards the roots of the plant. There is now much scientific evidence to support the fact that mycorrhizal fungi can provide a reliable natural mechanism for plants to enhance drought tolerance.

9 Common plants shown to benefit include tomatoes, roses, corn, ornamental flowers, shrub and tree species, but most plants (around 95 per cent) benefit from a mycorrhizal relationship. This data, collected through scientific field trials, as well as those done under more commercial situations through observations, shows a strong trend that applying mycorrhizal fungi to freshly planted plants can enhance survival rates and drought tolerance in the difficult first three years of establishment. How mycorrhizal fungi enable plants to resist drought Rootgrow mycorrhizal fungi of (white fibrous strands) growing with the roots of young plants create a massive surface area to supply the plants with water and nutrients. This is the natural condition of undisturbed soils. Easy to apply, Rootgrow allows you to recreate this status quo. A plant without these fungi relies on routine high levels of irrigation or welldistributed rainfall. Under reduced water availability the fungi enable the plants to function for longer and extract the maximum amount of water remaining in the soil. This is accomplished by the huge volume of soil explored by the fungal strands - in 7 kg of soil there could be up to 7 kilometres of mycorrhizal fungi root. Nutrients can therefore be taken up for plant development whereas a nonmycorrhized plant would have simply shut-down. The fungi exude a sticky glue-like substance in the soil which hosts many beneficial bacteria as well as building the soil structure and keeping it close to the plant roots. This is important for nutrient uptake. The fungi also seem able to increase the rate at which water is moved from roots to shoots in plants, an indirect mechanism for better water uptake. Low levels of water in the soil means that no nutrients will move towards the plant roots if the fungi are absent (remember there are up to

10 14m of such fungal strands in a sugar cube sized volume of soil). Therefore the fungi actually take up water in these fungal strands and move it into the plant roots along with many important nutrients like phosphates and other elements important for plant growth and survival. The benefits to the plant of its friendly fungal partner actually increases as the drought conditions get more severe. These fungi are symbiotic organisms and cannot survive without a host plant. Therefore it is in the fungi s interest to keep its host plant alive at any cost. Rootgrow is easy to apply. It can even be applied to established plants by a number of methods. It is cheap and safe to use, you cannot overdose the plants and it has no side-effects. Needing no chemicals for its best use, it is the ideal solution for growing organically. When you buy Rootgrow from us, we will be able to supply you with all the information you need for its use, including advanced techniques. Remember, we have been using and supplying Rootgrow at manufacturer s prices since 2004, which is even longer than the endorsement by the RHS.

11 4 Using Water Wisely East of Eden Shrub and Tree Irrigation System With more mature shrubs and trees the demand for water after planting far exceeds the typical rainfall supply. Hosing around the tree often results in the water running over the root-ball into the surrounding soil, with little value to the plant and wasting a valuable resource. In fact, as with all top-watering, as the root-ball dries out, the surrounding soil can become so waterlogged that new roots emerging rot before they can develop. This applies to plants in pots, as well as in the natural soil. With tree planting in dry areas of the world, such as the tree planting project in Malta (right), large pipes are used to deliver water to the roots. Based on our experience on large scale planting projects, we can now offer a domestic and inexpensive system for both amateurs as well as professional gardeners and landscapers. As illustrated below, the units direct the water to the inner regions, as well as below the root ball encouraging the new roots to grow downwards for future viability. Drought stress remains one of the biggest factors to high mortality rates of transplanted trees in their first few years of establishment. Water at this time is vital for tree growth and sustainability. Lack of regular watering in the early years will without doubt cause irreparable damage to the tree. During the summer period a 6cm girth tree will typically require at least 30 litres of water per month and a semi-mature tree, with a girth of 20cm or more, will need 300 litres of water per month. The use of a 'targeted' irrigation system that delivers water directly to the root zone provides a huge benefit to the development of the tree. The difference in large shrubs and trees planted with and without irrigation systems is striking.

12 An entry pipe above soil level ensures water is easy to apply. A porous irrigation pipe allows water to be delivered to the base of the plant where it is most effective, and is also most easily conserved. The entry cap keeps soil out of the pipe when not in use. Finishing at soil level, the system is unobtrusive. The overall system is used in combination with planters that shed excess water, keeping the plants watered within controlled and tolerant ranges.

13 Irrigate with East of Eden Self Watering Tanks designed for the soil, pots and planters As with our gold-winning water-wise garden collaboration with Wendy Allen at Chelsea, our own marshalling and deployment of simple and costeffective water controlling technologies are tried and tested methods of conserving water for maximum benefit. Wherever the project is, we can design and supply a planting solution that fits the location. Choosing the plants always comes first. They have to be selected carefully, whether indoors or out, to suit the available light and other conditions. The soil and water requirements of the plants then dictate the kind of planter and irrigation system required. With increasingly severe limitations on conventional watering techniques, our methods are more efficient systems that use less water, or use brown conserved water.

14 There is a Chinese saying, You will know at the harvest that laziness is not planting. We would add to that, You will know in the drought that planting with insufficient preparation is inexperience. By following our guidelines you will gain and benefit from that experience. Whether you have green fingers or not, East of Eden Self Watering Irrigation Systems get the green thumbs up. References You can check your local soil type using Cranfield University s Soilscape map Further information about soil and its capability for water storage is below: Centre for Ecology and Hydrology British Hydrological Society To talk to us about products and services to help you create drought control in your project, please use our contact form. You can also send us images. You can also telephone us