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|  The benefits of aquatic plant repotting and dividing....Pond plants are just the same as any other plant, in that they have similar needs. Any plant that is growing in a container that is too small or overgrown is restricted in their growth. This reduces the potential of new growth and their ability to flower. Overgrown pond plants can easily be divided to produce more plants. Old growth can be cut away and the healthiest plants may be kept to produce the best show. Healthy vigorous plants are always more resilient to attack from pests. Dividing plants allows us to control their growth by reducing their size, if required, or to improve their growth in the following season by adding fresh soil and fertiliser when they are replanted/repotted. We have trialled many products and discovered the benefits that our Oz Watergardens Aquatic Planting Mix has in improving the properties of any aquatic soil and the results are healthy strong water plants. When should water plant repotting and dividing be done? Most aquatic plants can be repotted and fertilised during the growing season. The warmer water allows them to grow, settle in and re-establish themselves in the new soil. Plants with yellow blotches on their leaves, small leaves or little or no flowering generally need to be fertilised or repotted. More robust aquatic plants such as Hardy waterlilies can be repotted any time of the year, in Australia. At Oz Watergardens we pot over 15,000 waterlilies each year. Our Winters (in Victoria) are not harsh enough to cause any problems or set backs to the plants. If however, your water lily plants have very small, weak rhizomes (the underground root), then we suggest that you repot when they are just starting to grow in Spring. More tropical water plant repotting should only be done when the weather conditions are warmer and the plants have begun to actively grow. Dividing and repotting these plants during Winter in the cooler climates, while they are still dormant, can lead to plant losses, as they do not have the strength or vigour to recover and grow away again. The benefit of water plant repotting in Winter is that the plants are dormant, we can clean up and trim away dead foliage and the pond normally takes a good month to re-establish its natural ecological balance. If we do it later in Spring, the algae can take off in the warmer water before the plants have had enough time to settle and recover. What should I use when water plant repotting? Water plants can be repotted into Oz Watergardens Aquatic Planting Mix or a good quality heavy topsoil, preferably a silt/clay loam soil. We actually recommend a blend of both. If you have a soil that you can grow good quality vegetables in, then this soil will be good enough to grow aquatic plants. Add 15-20% Oz Watergardens Aquatic Planting Mix, to enhance the soil. This doubles the benefits, as you improve your soil with the properties of the Aquatic Planting Mix plus you benefit from the cost savings. Choose wide shallow pots (preferably black). These will be hidden under the water so any appropriate recycled container can be used. Container size will dictate how big the plant can grow. If you need to control and restrict the growth, use smaller containers. Water lilies are heavy feeding plants and need a container that is at least 20cm in diameter. If you grow a waterlily in a smaller pot, then you limit the ability for the roots to support the leaf growth and potential flowering. The how to's....of aquatic plant repotting.... Most aquatic plants are perennials and hardy waterlilies are often the easiest example to use. Perennial plant repotting and dividing is treated in much the same way as most aquatic plant repotting. Hardy water lilies produce leaves and flowers that float gracefully on the pond surface. These leaves and flowers grow up to the surface from a rhizome that grows horizontally under the soil. When dividing and repotting hardy waterlilies, it is the rhizome that we are dividing and repotting. • How often? For strong healthy plant growth, hardy waterlilies can be divided and repotted every year, however, we generally find that every 2 years is sufficient, provided that they are kept well fertilised. • Plant preparation Remove the soil from the waterlily, using a hose or dipping into a bucket of water to expose the rhizome. Select the best growing shoots and cut them away about 8-10cm back from the growing tips (where the leaves are sprouting from). Discard the remainder of the plant. Trim away the excess roots and damaged foliage from the selected piece/s. (If the water lily rhizome is to remain unpotted for any length of time, it can be wrapped in damp paper, or floated in clean water and stored in the shade). • Soil preparation Soak some Oz Watergardens Aquatic Planting Mix, in a bucket of water, to rehydrate the dry material (otherwise it will draw the moisture from the plant roots and dry out your pond plant). Thoroughly mix 15-20% of the pre-soaked Oz Watergardens Aquatic Planting Mix with some good quality heavy topsoil, preferably a silt/clay loam soil. • Container preparation Choose your container (at least 20cm wide or more) and fill ¾ with your aquatic planting soil. • Fertilising Add 2 x (10gram) slow release fertiliser tablets to the soil. • Planting Create a hollow on one side of the pot so that the soil is mounded up at a 45° angle towards the other side of the pot. Place the rhizome at a 45° angle, with the cut end against the side of the pot and the growing point level with the top of the soil (aimed towards the centre of the pot). The reason for this is that the waterlily rhizome will continue to grow across towards the other side of the pot. Add some more soil around the rhizome and fill the pot to about 5cm from the top, taking care not to bury the growing tip. Firm the soil to hold the rhizome in place and add 2-3cm of clean pea-sized pebbles or gravel (again taking care not to bury the growing tip). • Water Gently add some water to the container so that it slowly becomes saturated and most of the air bubbles have stopped. Slowly lower the plant into the pond. TIP You may wish to place the plant just a few centimetres under the water for the first couple of weeks. The upper surface pond water is warmer and you will get faster growth. Later you can lower the plant to the recommended pond depth of about 45cm. See Pond Plant Zone Map for more info on recommended pond depths for all pond plants. |
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