Small Garden Pond and Water Garden Plants
Caring for the Small Garden Pond and Water Garden Plants
Thinning out and cutting back
It is essential to thin out and cut back fast-growing pond plants as the plants tend to reduce the surface area of free water and rob other plants of space and light. Dead and decaying plant stalks should also be removed as they interfere with the quality of the water.
Rhizomes growing out into the pond are very visible and easy to cut off. Use a tree-pruning tool with a long handle, with which you will be able to reach plants quite easily from the edge of the pond. Such a tool can be obtained in any good gardening shop or centre. Cut off all rhizomes which are growing further than 30 cm (12 in) out of the container. Cut those hanging over the edge of the container only so much that they still cover the edge.
Use a sharp knife to cut the thick stalks of reeds. Hedge clippers are also suitable for cutting reedmace. Cut off the plant stalks about 5 cm (2 in) above the surface of the water, otherwise the plant will decay.
Cutting back fast-growing marginal plants in the pond floor
If marginal plants start to grow too far towards the middle of the pond, the rhizomes should be cut off as near to the edge of the marginal zone as possible. If you cannot reach rhizomes growing into the pond floor, cut off the young plants that have grown too far into the middle, making sure you cut them as near to the rhizomes as possible and under the surface of the water.
Underwater plants as nutrient traps
Use plenty of underwater plants in your garden pond. They grow fast and will absorb lots of nutrients. If they grow too much, however, you should remove about half of the total quantity in late summer. This will reduce the nutrient supply of the pond. Use a rake with blunt teeth for this operation. The underwater plants that have been removed should be stacked in a heap very close to the pond for about a day, in order to enable any water creatures that have been scooped up by mistake to find their way back into the pond.
Care of waterlilies
Water-lily have different requirements for care depending on the species. The familiar white water-lily ( alba) is very robust and easy to care for, while tropical species and some cultivars are very sensitive and will only flourish under optimum conditions.
Care of rhizomes
Before planting the rhizome, remove all decaying parts. The end of the rhizome will nearly always be decayed which is easily recognizable by the bad smell and the soft, spongy tissue. Use a sharp knife to shorten the rhizome so that all decayed roots are removed. Decayed parts in the front part of the rhizomes should also be completely cut out. A budding knife is useful for cutting out small patches. Protect the wounds from further decay by using a paintbrush to paint active charcoal or charcoal powder on to the cut surfaces.
If plants have become too dense, are creating too much shade or the water is becoming too shallow, the water-will begin to stack their leaves on top of each other and produce very few flowers. If there is too much shade or the water is too shallow, you should take the plants out and plant them in a more favourable position. If the plants have become too dense, either take out individual plants or cut leaves off some of the stronger ones. Do not tear off the water-lily leaves as this might damage the rhizome. Instead, cut off the leaf stalks with sharp scissors or tree clippers, under the water and close above the rhizome.
Even if the water-lilies are in a good position and have enough room, the leaves may end up growing above each other and riding up. We recommend giving the plant a rejuvenation cut. This operation should be carried out in the autumn or spring. Remove the entire plant from the pond and cut off the daughter plants wherever the rhizomes branch out. You can prepare the rhizome of the strongest plant for planting. Often several water-lily plants will have been created as the connections at branching points have decayed. In this case, take out the weaker ones and only put the strongest ones back into the, pond.
If your water-lilies remain small or do not grow much in spite of a favourable position and plenty, of room, they are probably suffering from nutrient deficiency. In such a case, you should change the planting compost. This deficiency does not often occur in plants which grow out of the floor of the pond as, generally, there are enough nutrients at their disposal. Plants in containers, on the other hand, frequently suffer from nutrient deficiency. Remove the plant container from the pond in the autumn or spring and carefully take the plant out. Fill the container with fresh compost.
Thinning out and cutting back the plants
Thinning out and cutting back is not only important in the care of pond plants but also decreases the nutrient content of the pond water. Many nutrients are bound in plant matter and would naturally dissolve back into the water when dead parts of plants decompose. Thinning out or cutting back should be carried out when:
- fast-growing species smother smaller, light-loving plants;
- if you have species in your pond, such as reedmace, which form rhizomes. Cut off the rhizomes growing towards the middle of the pond as they will rapidly reduce the expanse of open water in smaller ponds;
- if floating plants are growing so vigorously that they are covering large parts of the surface of the water. Fish the plants out or the underwater plants will suffer from light deficiency.
What to watch for when cutting back
- When thinning out marginal plants, make sure to cut them above the surface of the water in order to prevent decay. If you cut them off: under the surface of the water, water will penetrate the air-filled tissues and the oxygen supply to rhizomes and roots will suffer. The plant will begin to decay.
- Cut back in a way that will decrease overshadowing of smaller species which are usually those most in need of plenty of light.
- Plants which do not grow very well should not be cut back much as they might then be overtaken by faster-growing competitors.