Choosing a Site for a Garden Pool
There are several things to consider when planning a water garden. Not just practical points to take into account, but aesthetic considerations which in the end will have an overwhelming influence upon the success of the venture. Certainly time and thought given to selecting a site is not wasted, for unlike many other garden features, a pool once constructed is not easily moved.
In order to come to the correct conclusion we should heed the words of Alexander Pope:
‘To swell the terrace, or to sink the grot; in all, let Nature never be forgot.’
Seldom is water discovered naturally above the lowest level of the ground. Only when trapped will it remain in such a position, looking distinctly ill at ease and impatiently waiting to cascade down to lower reaches. Only in a formal garden, where the pool is contained within a raised walled surround, does water rest in peace.
In an informal setting water has to be at the lowest level in order to be in conformity with its surroundings. Unfortunately, this is not always the best position from the gardener’s point of view, for such a situation may be beneath overhanging trees or in the shade of a high wall. When such a problem presents itself, the only way it can be overcome is by skilfully planting the garden to create the illusion that the pool is in fact in a natural situation. Excavated material from the construction can be used to raise the surrounding ground level and will do much to assist in this trickery.
Ideally, a pool should be sheltered from cold easterly and northerly winds by a fence or low wall. Or if an integral part of a rock garden, then should preferably be constructed to the south or west of protective rocky outcrops. It is surprising how much effect even modest protection from cold winter winds will have upon the degree of freezing within the pool. Any reduction in icing and increase in protection for emerging plant growth in early spring is most welcome.
The limits imposed by aesthetic considerations can present practical problems. These are not normally insurmountable, but the aspiring pool owner should be aware of them at the outset. Aquatic plants, for instance, require full uninterrupted sunlight if they are to prosper. Such conditions encourage prolific growth which is essential both in maintaining a balance within the pool as well as providing much appreciated surface shade for the. Pools constructed in the shade are invariably gloomy and are difficult to establish a balanced collection of plants in. They are, therefore, almost always anaerobic and evil smelling.
Close proximity to deciduous shrubs can bring trouble. In the autumn blowing leaves are likely to accumulate in the water unless care is taken to cover the pool with a net. If a pool has to be built in such a situation this precaution should not be disregarded, for decaying vegetation in the water generates toxic gases which can be lethal to the fish. Especially if the pool becomes covered with ice during the winter and these gases have no means of escaping into the air.
Not only can the foliage of decaying deciduous species be harmful, but evergreens likeand laurel have leaves which are extremely toxic to fish. So are the seeds of the lovely spring-flowering laburnum. These contain a readily soluble alkaloid which will very quickly poison fish.
Other trees, particularly those of a weeping nature which are normally associated with water, must not be allowed to overhang the garden pool. That is the pool should not be constructed in the proximity of an established tree nor at a later date should any such tree be planted nearby. The reasons for this are many, not least of all the problems likely to be encountered with strong probing roots disturbing the pool foundations.
Apart from this, and the normal problems associated with pool contamination from falling leaves and other debris, there is the question of insect pest control. Many tree species harbour the overwintering stage of troublesome pests. Of these, the waterlily aphis is of the greatest concern to the water gardener. This causes extensive disfigurement of aquatic plants and spends the winter on the boughs of flowering cherry and plum trees. Of course some measure of control can be effected during the winter by spraying the trees with tar oil winter wash. However, this task is impossible in the case of a weeping cherry which overhangs a pool, a situation to be avoided at all costs.
A final, and often overlooked, consideration is the provision of electricity. Certainly ifor artificial lighting are contemplated this must be close at hand.