What factors should I consider when deciding where in a garden to site a pool?
Pools should be sited on level ground, at the foot rather than the top of a slope, in as full sunlight as possible and away from deciduous trees that will shed their leaves into the water.
Some things apply to all pools, whilst others can only be answered when you have decided on the form that your pool should take. It's most important that the pool shouldn't be overhung by large deciduous trees which will deposit foliage into the water every autumn. If these are allowed to remain and decay, they will foul the water by using up oxygen at a time of year when the oxygenating plants are dormant are thus unable to replace it. Remember too that tree roots can undermine a pool as easily as they can any other structure and cause leaks.
Sunlight is the most important single factor for the correct functioning of a pool as there are almost no surface living water plants that are shade tolerant whilst water-lilies especially need six or more hours of direct sunshine per day.
A pool must be on level ground, but if it is sited at the base of a steep slope, water draining from the rest of the garden will end up in the pool which will constantly overflow and create boggy conditions in the surrounding area; which is excellent if you plan to have a bog garden.
Finally, don't forget the aesthetic aspects of siting a pool. A formal pool requires formal surroundings and whilst it is perfectly at home in a paved courtyard, it will look ludicrously incongruous as the focal point of a rock garden. There you need a pool that resembles, as closely as possible, the appearance of a natural pool in such a spot.
What is the most satisfactory material with which to construct a pool?
A pre-formed liner is easiest; a flexible butyl rubber liner more adaptable. Concrete or traditional puddled clay liners aren't recommended for normal garden use.
The traditional way for pools to be constructed was with trampled ("puddled") clay but it really isn't practical for a garden. Puddled clay was replaced as a pool liner by concrete and this is still used to some extent but it too, isn't easy to apply. The simplest methods are with modern plastic liners. Polyethylene ("polythene") sheet isn't satisfactory as even the very heavy gauge tears easily. Much better is butyl rubber . This is quite costly but extremely tough; and you should buy the best quality you can afford - it tends to be sold by the length of the guarantee rather than the thickness. The simplest pool liners of all to install are the pre-formed glass fibre creations that look a bit like over-sized baby's baths. They are very tough but obviously the shape is predetermined and I find them harder to disguise than butyl rubber liners.
Is there a minimum size below which a pool doesn't 'work' properly?
It really depends on how you define a pool. I believe that about 2 x 1 m should be the minimum dimensions for anything worth calling a pool, although a tub garden using a wooden half barrel can be smaller and very effective.
Wooden half-barrels make very good tub gardens, but be sure to choose a genuine barrel. Those made-up versions sold as plant tubs aren't satisfactory because the joints won't close when the wood swells and they will always leak. You can grow a few of the smaller water plants , including the miniature water-lilies ; plant them in plastic containers, covering the soil, as usual, with gravel. Remember to add half a dozen bunches of submerged oxygenating plants and you will find that a pair of small fish and a few water snails should live in such a tub garden quite happily.
Does a fountain help to keep a pool in a healthy condition or is it merely ornamental?
It is mainly ornamental although a fountain is very valuable in oxygenating the water and in keeping an area ice-free in winter.
It is important to choose fountains and pumps carefully because a highly ornamental display incorporating several fountain jets in a fairly small pool can be detrimental to the plant life by over-cooling the water. I don't like to see fountains in a semi-natural pool although a pump there can be used very effectively to create a small water-fall. Modern pump kits offer you a wide range of options to create a water display appropriate to every setting. If you choose a mains voltage pump rather than a low voltage version, it must be installed by a qualified electrician.
What is the best time of year to set up a new pool?
The best time to plant a pool and then introduce the fish is in the spring and early summer but the pool itself could be built in the autumn.
Plants put into a pool during the autumn will almost always fail to establish before the water temperature drops and they will then rot away during the winter. Nonetheless, bear in mind that building a pool of even moderate size can be quite a lengthy operation and there is certainly an advantage in having the basic excavation made during the autumn. Bear in mind too that aquatic plants are usually only available from spring onwards.
How important is it to break the ice on my pool in the winter?
It is very important that you don't break it at all; at least that you don't take a hammer and smash it but you must keep a small area ice-free to enable oxygen to enter the water and harmful gasses to escape.
The best methods to keep an area of pool ice-free are to keep a fountain running or to install a small low-voltage pond heater . Floating a rubber ball in the water never works in my experience and looks pretty ridiculous.
How should I set about deciding which plants to buy for stocking a new pool?
You will need plants representative of several different groups: submerged oxygenating plants, true water plants like water lilies, floating plants, marginal plants and, if you have an adjoining bog garden, bog plants .
The following lists give the quantities of plants suitable for pools of different sizes. Note that the depth I have quoted is that in the centre of the pool - much shallower water will be needed at the edges for the marginal plants to establish satisfactorily:
Small Pools (approximately 1.75 X 1.25 m. 30 cm deep)
Oxygenating Plants 10 bunches
Marginal Plants 6
Water Lilies 1
Other Pond Plants 1
Floating Plants 4
Medium Pools (approx. 3 X 1.75 m. 45 cm deep)
Oxygenating Plants 25 bunches
Marginal Plants 8
Water Lilies 2
Other Pond Plants 2
Floating Plants 7
Large Pools (approx. 4.25 X 3 m. 55 cm deep)
Oxygenating Plants 80 bunches
Marginal Plants 20
Water Lilie s 4
Other Pond Plants 6
Floating Plants 20
What plants do you recommend for a pond?
Oxygenating Plants:
Elodea canadensis - Canadian pondweed
Ceratophyllum demersum - Hornwort
Myriophyllum spicatum - Milfoil
Hottonia palustris - Water Violet
Marginal Plants:
Alisma plantago - Water Plantain
Butomus umbellatus - Umbrella Rush
Caltha palustris - Marsh Marigold
Iris laevigata
Menyanthes trifoliata - Bog Bean
Myosotis palustris - Water Forget-me-not
Pontederia cordata
Sagittaria sagittifolia - Arrowhead
Veronica beccabunga - Brooklime
Water Lilies
Other pond plants:
Aponogeton distachyum - Water Hawthorn
Sagittaria natans
Orontium aquaticum - Golden Club
Villarsia bennettii - Fringe Lily
Floating Plants:
Hydrocharis morsus-ranae - Frogbit
Stratiotes aloides - Water Soldier
Should I put the fish into my pool at the same time as the plants?
No. It is important that the plants and the water are given ample time to settle down before the fish are introduced. I like to allow three or four weeks at the least.
A three-week gives the plants time to take root satisfactorily; new fish are remarkably inquisitive and can very easily dislodge plants before they have established. Remember that, as with plants, it is important to choose the right quantity of fish for the size of pool. Remember too, that you will need a proportion of bottom-living scavengers among the fish, and a small population of water snails (preferably ramshorn snails and freshwater winkles) too. The following numbers of fish such as goldfish, golden orfe and shubunkins should be adequate for typical pools:
Small Pools (approx. 1.75 X 1.25 m. 30 cm deep)
10 fish of average length 8 cm long and 1 scavenging fish.
Medium Pools (approx. 3 X 1.75 m. 45 cm deep)
20 fish of average length 8 - 10 cm and 3 scavenging fish.
Large Pools (approx. 4.25 X 3 m. 55 cm deep)
25 fish of average length 12 - 15 cm and 5 scavenging fish.
What is the best way to plant pond plants?
In a purpose made planting basket with nutrient-poor garden soil or special aquatic plant compost. Never use fertilisers or normal compost.
Water plants (apart, of course, from the floaters), need something to root in as just much as any other plants do. There are certain rules to remember with water plants nonetheless; always plant them into purpose made aquatic plant compost or poor soil, not into any organic compost, manure or leaf mould because this will rot in the water and deplete the pool of oxygen. Remember too that fish will very happily stir up soil in the water and make the whole pool cloudy unless a layer of gravel is placed over the soil to prevent this. The planting is best done into loam-filled ledges built into the sides of the pool or, more conveniently, into planting baskets ; formerly wicker baskets were used but modern plastic baskets available in a range of sizes are better. Remember to spread the roots well, not to cover the crowns completely, to position the baskets at the recommended planting depth for the particular species and, if after buying or receiving your plants, you are unable to deal with them promptly, do make sure that they are kept in buckets of water and never allowed to dry out.
Why does the water in my pool often turn murky; what can I do to remedy this?
There are several possibilities: if it turns brown and muddy, this will be due to bottom-living fish churning up the mud; if it turns green in summer, this is due to microscopic green algae.
Everyone's pool water turns cloudy or murky at some time or another, so don't worry unduly. With a newly planted pool, the murkiness is usually due to the presence in the water of particles of mud. These will settle out in time although it makes sense to avoid using a clayey soil for planting baskets.
Once a pool is well established, the water, which may have remained crystal clear through the winter, will suddenly turn cloudy in the early summer and periodically continue cloudy through the season. This is almost always due to the natural build-up in the pool of micro-organisms and provided a careful balance of plants, including adequate oxygenators, has been chosen, no organic matter such as manure has deliberately been introduced and leaves have not been allowed to accumulate, there really is no cause for concern. In time, clarity will return. It may be possible to hasten this by adding a chemical algicide but unless the water has become seriously green I prefer to let nature take its course. If an algicide is used, be sure to dilute it as the manufacturers direct before adding it to the water.
How can I remove the green growths that appear in my pool during the summer?
Floating, tiny pale green plants are duckweed; submerged, darker green growth like cotton wool is blanket weed. Both can only effectively be removed by netting.
The 'green growths' are the water garden equivalent of weeds. The two commonest problems are duckweed, a minute species of flowering plant with leaf-like growths which give it buoyancy, and the masses of green filamentous algae, rather like green wool, that grow below the surface and can rapidly block up a pool in some seasons. Duckweed reproduces at a prodigious rate, simply 'budding off' new plants without needing to produce seed. In moderation, duckweed is rather attractive and physically scooping it up with a net once it begins to take over really is the best that you can hope for. It is impossible to remove all of it, and even one plant left behind will soon start up the colony afresh.
The growth of filamentous alga (blanket weed or 'slime' as most people call it), is rarely controlled very satisfactorily with chemical algicides and, even then, you are faced with the problem of removing the dead material before it rots. I prefer to scoop it out regularly with a wooden rake. At least, any left behind will still be living and won't therefore decay and foul the water. Be sure not to use a sharp metal tool, however, especially in a pool with a plastic lining.
Which types of water lily should I choose to give the best colour in my pool?
There are many different varieties of water lily, varying, not only in colour, but also in vigour of growth, preferred depth of water, flowering time and length of flowering season. How many plants and which varieties you choose depend, firstly, on the size and depth your pool. In a small pool, there will very probably be room for only one or two plants, even of the less vigorous varieties.
The following variety lists should help you to choose plants suitable for your size of pool and depth of water, but remember that there are dozens of different water lily hybrids and that we can't guarantee to have any particular variety available all of the time.
V = very vigorous
Surface spread 1.5 m diam.
Water depth 30 cm - 1.5 m
M = moderately vigorous
Surface spread 1 m diam.
Water depth 20 - 60 cm
S = small
Surface spread 60 cm diam.
Water depth 15 - 45 cm.
T = tiny
Surface spread 30 cm.
Water depth 10 - 30 cm.
White varieties
alba V medium-sized flowers; needs really deep water
Marliacea albida M huge waxy flowers with yellow stamens
odorata alba S pure white flowers; strong scent
pygmaea alba T the smallest of all water lilies
Pink varieties
Colossea V very long flowering season
Marliacea carnea M white flowers with a pink tinge
Pink Opal S star-shaped flowers; strong scent
Laydekeri rosea T deep rose coloured flowers; strong scent but not the most vigorous grower
Red varieties
Conqueror V masses of flowers with white flecks; very vigorous
Escarboucle M the finest of all water lilies; crimson-red with orange stamens; very free-flowering
James Brydon S rich red with orange stamens; excellent and tolerant of some shade
Ellisiana T vivid dark red flowers contrast with dark green leaves
Yellow varieties
Col. A. J. Welch V star-shaped flowers; marbled leaves
Marliacea Chromatella M very free-flowering; a very soft yellow
Sunrise S dark green leaves and probably the largest of all flowers - up to 30 cm.
Pygmaea Helvola T marbled leaves and very soft, sulphur yellow flowers
What is a bog garden and how do I make one?
A bog garden is simply a small area of garden in which the soil is permanently wet and where plants that thrive in these conditions can be grown.
A bog garden can be constructed anywhere that water is continually available; close to a garden pool (provided it isn't a formal pool with paved edges), in a low lying hollow that doesn't dry out, and at the foot of a slope if drainage water can be suitably directed; but not, please, somewhere made wet simply by leaving a garden tap permanently dripping onto it. We have a wide range of suitable bog plants .
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