Rock garden examples to include different types of garden feature for the display of alpines, rock garden, scree garden, troughs; and the materials to include suitable types of stone, hypertufa, artificial rocks, Pulhamite; artificial stone troughs.


Ideally constructed to imitate a natural out-crop of stone, exposed by the erosion/weathering of soil on a bank;

Uses: Can be drawn on in design to use or deal with a bank. Can be a major feature in its own right; Provide a planting area for rock garden/alpine plants (hobby/interest); Often built in conjunction with a water feature (pools, water falls, streams); (Other ways of providing for growing alpines: raised beds, sinks and troughs, alpine houses/frames).

Ideally sloping; Sunny aspect (south) not over-hung with trees or shaded by buildings; Soil naturally light (sandy to loam); Free draining. No wet spots at the bottom of the slope (might need drainage); Free from pernicious weeds (bind weed, couch, and ground elder); Not in a wind tunnel; Ideally with irrigation water available.

Materials: Natural: Local sedimentary stone (Portland & Purbeck – limestone, Shaftesbury – sandstone (green sand)). These have lines of strata; Look natural in the area (cohesive); Cheaper to purchase and transport; (The use of Westmorland limestone pavement is ACTIVELY discouraged).

Man-Made: Cast concrete or tufa:

Rogers “Hollowrock”: Building:

Start at the bottom with lines of stone to form a line of rock with the lines of strata horizontal and running from stone to stone; Move up the bank, producing planting ledges; All stones to be bedded in well for safety; No air pockets; Ideally do some planting as you build. Hazards and Risks: Weight of stones, back injury, pinched fingers; Stones wobbling or being slippery if walked on.





HYPERTUFA Hypertufa is an anthropic rock made from various aggregates bonded together using Portland cement. Hypertufa is intended as a manufactured substitute for natural tufa, which is a slowly precipitated limestone rock; being very porous, it is favorable for plant growth.


Pulhamite was a patented anthropic rock material invented by James Pulham (1820–98) of the firm James Pulham and Son of Broxbourne in Hertfordshire.

Pulhamite, which usually looked like gritty sandstone, was used to join natural rocks together or crafted to simulate natural stone features. It was so realistic that it fooled some geologists of the era.[1] The recipe went to the grave with him.[2] Modern analysis of surviving original Pulhamite have shown it to be a blend of sand, Portland cement and clinker sculpted over a core of rubble and crushed bricks.[3]

Water features to include: open water (raised and wildlife ponds, rills) and self-contained features (fountains, pebble ponds) and materials to include puddled clay, butyl liner, drilled natural stones, metal, glass and plastic, wood and brick for raised ponds.


Feature in own right; Enhance other features (rock gardens); Water brings sound and light reflection into the garden; Provides for growing aquatic plants or keeping fish.

Materials: Natural: Pond building/puddling clay; Water courses/natural stone, pebbles, boulders.

Man Made: Butyl rubber, plastic, fibre glass, concrete blocks and bricks.

Hazards and Risks: Drowning; Use safe water features, e.g., bubble fountain; Grille in water; Have in clear sight, not hidden; Electrocution; Have any pumps/lights professionally installed (Part P Planning Act); Be careful when using electrical equipment close to water, e.g., dropping hedge cutter in pool.


The ultimate water feature guide Create sound and movement in your garden with a fountain, wildlife pool or rill Attractive pond in a small garden giving a natural appearance by a grass edge and backdrop of moisture loving shrubs and perennials Want instant interest? Just add water Photo: GAP Photos/Graham Strong By Bunny Guinness6:00AM GMT 01 Mar 2015 To my mind, water is the son et lumiere of the garden. It adds sound and light and also brings in life. Water features are brilliant for increasing the enjoyment of gardens – but only if they work properly.

I first consulted Nick Roberts of Fountains Direct more than 30 years ago on a complex series of formal cascades for a client and quickly realised that a water feature engineer (although his wife calls him “the plumber”) could save a lot of floundering. I asked Nick, who installed the Fountain Court at Somerset House, about the pitfalls that most of us encounter when we get creative with water for our own gardens.

•View Britain’s best water features.


His first piece of advice is that it is important to design something you can live with and afford. A simple, informal wildlife pool can be stunning. It does not necessarily need fountains, sculptures or added glitz. You may not require or want the water to be gin-clear and can tolerate the odd few days in a hot, early spring when it may look like pea soup. Even so, you need the liner to hold water and you shouldn’t have to see it. EPDM (ethylene propylene diene monomer) liners (1mm thick) are now thought to be superior to butyl. I, like Nick, would always lay them over an underlay and then put another layer of underlay on the top for added protection. The underlay quickly takes on the sludgy colour of algae and disappears under a layer of pebbles or poor subsoil (rich soil encourages algal growth).

A wildlife pond can be an affordable and stunning way to add water (GAP Photos/Graham Strong)

To have a good pH balance with no algal outbreaks, ideally the pond needs an area of 400 sq m with a depth of 1.5m in places. My own pool is nothing like that, just 30 sq m. Generally it is well behaved, except in some early warm springs when we get blanket weed. Then I rush out and add barley straw extract (Aga Group) to control it.

Ideally, two-thirds of the water surface should be covered with floating plants (water lily, water soldier, frogbit) while three-quarters of the sides should be planted with marginal and emergent plants (water forget-me-not, flowering rush, marsh marigold). Weigh down bunches of submergent plants (such as spiked water milfoil) and throw them in. If the liner shows in places, coir sausages pre-planted with marginal plants are a quick fix (Verdant Solutions). These “natural ponds” never need cleaning. If the sludge gets pongy, add some AquaBio (calcium sulphate) in late summer from the Aga Group. Slowly the pond will become more healthy.

With any pool, if you want it crystal clear and to be able to see the fish all the time then you need a filtration system. That is, unless it’s just 200-300 litres and you are happy to drain it every couple of months, clean it and refill.

A filtration system is needed for crystal clear water (Alamy)

Nick says the Oase self-cleaning drum filters, which are either gravity-fed or pumped, are the best for amateurs. These must be installed outside the pool. He also reckons that if you put a fountain in a pool, it must look good when it is switched off. I agree, as elaborate figures pouring vases look strange when they are not working. A favourite of his is a Kadai fire bowl that sits in the centre of a circular pool and gently trickles over.

“If you want carp,” he says, “remember they dig up and remove everything, so the filter system has to be very sophisticated.” Generally, fish are not helpful for water clarity and it is easier to leave them out, though you will probably find, as with my father’s pool, that they just arrive. Five carp wafted in, probably as eggs on ducks’ feet.

I love rills in gardens. They can snake through in an informal fashion or can be used to add to the formality. Nick points out that the common problem with these is that the catchment tank (usually underground) is too small. It has to cater for the volume of water in the rill, plus that in the recirculating pipe and the volume of water required to cover the pump in the tank. Nick did one recently that was 90 metres long with a fall of 1:100. To create added movement in the water they put small triangular blocks on opposing sides of the rill every few metres so the water gave an attractive criss-cross pattern as it flowed through.

Rills can add a formal feel in a garden (Dariusz Gora / Alamy)

Water features lose water through evaporation far faster than is often thought. Nick has recently installed a polished black granite block, 1.3m wide and 600mm high, which has water trickling over it into an underground tank and back to the top again. It is in a windy site and so loses a copious amount for many months of the year. Automatic top-up units are now commonplace, using a solenoid valve. A sensor sits on the water line and triggers the pump to start. This usually costs about £600 to £700, but, by law, it cannot fill from the mains supply. It has to be from a “category five supply”, and installing the extra tank capacity might well cost £3,000 to £4,000. Filling with a hose is not such a bad idea!

Stainless-steel water walls were all the rage a few years ago. Quickly, inexpensive kits from China and elsewhere came on to the market. As Nick points out, you do get what you pay for with these. If you go for a budget version, site it so that any flaws are not obvious. As long as you don’t mind replacing elements such as the pump after a while, all is fine. It might well give you a lot of pleasure for not a lot of outlay.

As to Nick’s own garden, what does he have as his showpiece? Nick has a bubbling millstone (as does the Prince of Wales on his terrace at Highgrove). His firm sells them in kit form, a metre-diameter stone with a central thick foamy fountain jet that sits on a grating over a tank complete with an Oase pump (Nick wouldn’t have any other: remember, it’s a five-year guarantee if you fill in the form, otherwise only two) and LED lighting.

Millstones can make a strong garden feature (John Glover / Alamy)

“It may sound like the cobbler’s shoes,” says Nick. “But it runs from six to eight each day and I’ve cleaned it out twice and replaced the pump once in 20 years.”

If you would prefer some fountains in paving à la Somerset House, they are not difficult, he says. The paving must be waterproof, though, so the water is collected in channels. The cones that create the fountain jets pop up through the paving and there is an underground reservoir. Pay your money and take your choice



RILL a small stream. a shallow channel cut in the surface of soil or rocks by running water. variant spelling of rille. How to Build a Rill Water Garden A rill water garden resembles an industrial water feature. Related Articles 1 Maintain Water Gardens Without Pumps 2 DIY Garden Fountains 3 Roman Style Water Features 4 Build a Japanese Garden Bridge A rill water garden offers the sensual benefits of moving water to a contemporary home and garden design through its geometric-style architectural structure. As a narrow canal, a rill water garden feature can connect two different landscape elements, such as decks or other structures. Grow trailing or creeping plants along the edges of the rill for a softening effect.

Excavation 1 Dig a trench four inches wider and four inches deeper than the desired width and length of your rill.

2 Excavate a large hole at one end of the trench for your water reservoir. The reservoir can be constructed with sand, a pond liner and concrete, or it can be a buried container, as this portion of the rill structure is concealed. The larger the reservoir, the less often it is necessary to replenish the water supply.

3 Dig a narrow, shallow trench parallel to and approximately six inches from the rill trench.

Trough 1 Line the rill trench on the bottom and sides with a 1-inch layer of builder’s sand. Also line the reservoir unless you plan to bury a water tank – a bucket, wooden barrel or other container to hold water. Smooth the sand with a wide, flat board.

2 Place a layer of pond liner on top of the sand layer.

3 Measure the length and depth of your rill trench. Using a board that is as wide as the depth of your trench, minus 3 inches, cut the board to the length of your trench plus 8 inches. If you do not have a board wide enough, use plywood.

4 Nail stakes at each end of board that are long enough to be driven into the ground and still leave 3 inches between the bottom of the attached board and the pond liner in the bottom of the rill trench. Drive the stakes into the ground outside of the rill at each end. Space the board three inches from the pond liner on the side of the rill. Make and install the same kind of form on the other side of the trench.

5 Prepare concrete mix according to the manufacturer’s instructions. Pour a 3-inch-thick layer of concrete in the bottom of the rill trench. Fill the space between the form and the pond liner on each side of the rill with concrete to complete the concrete trough.

6 Allow the concrete to cure for five to seven days before you run water into the rill. Although concrete dries to the touch within a few hours, it needs additional time to reach optimal strength and durability.

Header 1 Construct a header – a wall that prevents water from escaping from the end of the water feature – 3 to 4 inches taller than the desired water depth of your rill, using bricks and mortar at the end of the trench opposite the reservoir.

2 Leave an opening between bricks near the top of the header. Make the opening wide enough for a piece of PVC pipe with a diameter large enough to allow a water pump tubing to pass through.

3 Mix mortar according to the manufacturer’s instructions. In the opening, mortar in a piece of PVC pipe that is as wide as the depth of your header wall.

Connect the Pump 1 Attach tubing to a recirculating pump according to the manufacturer’s instructions. Put the pump in the reservoir.

2 Run the tubing through the narrow trench beside your rill and push the end of the tubing through the PVC pipe in the header.

3 Put your electrical cord through a PVC pipe and lay it in the trench. Pull the plug end of your electrical cord out at the end of the PVC pipe. Cover the trench with dirt.

4 Fill the reservoir with water. Plug in the electrical cord to an outlet. Use rocks or wooden structures of your choice to conceal the reservoir and header. Install creeping plants or trailing plants at the edges of your rill to create a water garden. Finish off the top edge of your rill trough with bricks, blocks, rocks or other decorative items as desired.

Things You Will Need Shovel Builder’s sand Pond liner Concrete mix 2 wide, flat boards 4 wooden stakes Hammer Nails PVC pipe Bricks Mortar mix Trowel Measuring tape Recirculating pump Tubing







safe use of water in the garden, gives sound and light reflection):

PUDDLING to make puddle, clay or heavy loam is chopped with a spade and mixed into a plastic state with water and sometimes coarse sand or grit to discourage excavation by moles or water voles.



Puddled clay – a traditional pool lining Using puddling clay to make a waterproof lining for a pond is rarely mentioned these days – it’s all butyl, fibreglass and concrete. But before these modern developments, clay was the only suitable material available, and if you’re doubtful of it’s success, you’ve only to look around at our canal system – originally lined with puddled clay.

What exactly is puddled clay? It’s clay that has had all the air pockets squeezed out of it to make a solid, immovable, watertight layer. You have to do the puddling so it is a labour intensive method, but clay is cheap and provided you are careful, you should have a trouble-free pond for years. So a small pond in the back garden shouldn’t be a problem, should it? Read on to find out, and once you realise the problems, you’ll probably want to install a a pre-formed pond liner or a sheet liner instead!

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Pros and cons of puddled clay ponds Like all construction methods, there are advantages and disadvantages to weigh up carefully. Local advice is useful because it’s specific to your area – contact your county agricultural and horticultural college (online yellow pages) for information on soils in your area and advice on clay-lined ponds.

Contact your local wildlife trust/countryside ranger service (again, use online yellow pages or your local council’s website or library) for information. They are quite likely to have created wildlife ponds from puddled clay and will be able to show you them and give tips. You may be able to join volunteers in creating a pond too, gaining valuable experience.

Advantages Low cost of materials – either your own clayey garden soil (free), or special puddling clay (cheap). Natural looking pond. An excuse for a party – invite your friends to bring their wellies to a puddling party. Disadvantages High cost of transport of puddling clay – especially over long distances. Your site may not be suitable – see next section. Essential to keep the pond full to the brim so that the clay never dries out and cracks around the edge. A clay lining is thicker than a sheet liner, so you need a bigger hole, which takes longer and creates more spoil. Time consuming to puddle the clay by foot or machine. For large-scale works you need tracked machinery to run back and forth to squash out the air – potentially expensive. Puddle clay suppliers can advise on machinery required.

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Is your site suitable for a clay pond? Puddled clay needs a firm base, so you cannot use this method on recently disturbed land, or too near the edge of a slope where soil may creep downwards or subside.

Some soils are unsuitable too. Gravelly, silty and peaty soils are affected by ground water and move. The puddle clay will also move, resulting in cracks and leaks.

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Can you use your soil to make a puddled clay pond? Take a handful of moist soil, rub it between your finger and thumb and mould it in the palm of your hand. If the soil is sticky, workable like Plasticine, stains your skin, can be smoothed and made shiny, and doesn’t crumble when released, it’s clay. This is quite likely to be found at a depth, but soil from nearer the surface may crumble when released. This is a clay loam. Dark soils are due to decomposing plant material; a gritty feel means there’s sand or gravel. Silty soils feel silky but you can’t smooth and polish them. Good garden loam feels neither sticky nor silky.

If you have really clayey soil in the garden, the action of digging may smear the sides of the hole sufficiently to keep water in. It’s worth digging a trial hole and filling it with water to see how long it remains full. The depth of topsoil will determine the final water level. Water may leak away through the topsoil, but should be retained by the subsoil.

If the soil isn’t clayey enough to hold water without help, then try smearing the sides of the hole with a thick layer of wetted soil from the spoil heap and puddling it to create a watertight liner. However, any stones or organic material present will prevent you from being able to squeeze out every last gasp of air from the clay lining.

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How much clay is in your soil? The ideal minimum clay content of a soil for a leakproof pond is 60%.

To test your soil, take a sample, let it dry out, then break it up as well as you can before adding it to a container of water. A tall straight-side container (e.g. a spaghetti jar), is best because it’s easy to see the relative amounts of each consituent. Half-fill the container with water, add the soil, then top up with water. Turn it upside down as many times as necessary to get the soil in suspension and then watch the soil settle out.

Most of the larger particles of sand will settle in about 20 minutes, with the fine clay staying in suspension for a long while and any organic matter floating to the surface. Once all the soil has settled, measure the total depth of the soil in the container, plus the amount of organic matter. Then measure the depth of clay particles (ie those that are obviously not sand).

To calculate the amount of clay:

  1. Divide the depth of clay by the total depth of all the soil and the organic matter.
  2. Multiply the answer by 100 to obtain the percentage of clay. eg. if there’s a total of 10cm of soil and organic matter, of which 2cm is clay, divide 2 by 10 (=0.2), then multiply by 100 (=20) to obtain the percentage (20%).

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Buying clay If your soil isn’t usable, look in the Yellow Pages or the online yellow pages, and other directories for clay suppliers. If they don’t supply puddle clay they’ll probably know who does.

Clay doesn’t cost much, but moving it around does. If you live in the right area, then the price of the clay plus transport could well be less than a butyl liner.

How much clay will you need? The clay lining should be at least 15cm thick, preferably 25cm thick to reduce the risk of damage by accidental prodding, vandalism, plant roots and worms. An even thicker layer is necessary for large ponds and lakes – ask the clay supplier for advice.

Estimate the area to be lined in the same way that you would for a sheet liner. There are two ways of calculating this:

If you have already dug the hole, drape a tape measure inside from edge to edge. Measure the length and width. Multiply together to obtain the area. If you haven’t dug the hole, mark the outline and measure the length and width on the ground’s surface. Add on twice the planned depth to each measurement. Multiply the result to obtain the area. Ask the clay supplier for a quote for sufficient clay to cover this area to the required thickness.

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Planning for a clay-lined pond For any pond, the longer spent on planning, the better the result. The shape, siting and finishing of any pond are important, no less for clay.

Existing vegetation Don’t site your clay pond near trees because the roots will make digging difficult, and future growth will probably break through the clay. As a rough guide, tree roots extend as far outwards as the branches, with poplar and willow twice as far.

Also beware of other nearby vegetation that could cause problems later. A lawn leading up to the pond looks lovely, but if your lawn contains couch crass then you’ll be in trouble. Couch grass has very invasive roots (rhizomes) – you’ll spot them once you begin digging. If you have this plant, the best solution is to spray off the future pond’s surroundings with a translocated weedkiller such as Roundup, which is taken up by the leaves and transported to the roots, so will kill all the greenery that it touches.

Fish and pond plants Plan the pond depth to ensure any fish will survive winters in your area.

Also plan for plants. You can’t plant into the clay, so plan shelves at the correct depth for baskets of marginal plants. Also check on the depths that deeper water plants (such as water lilies) need to thrive.

Finishing off the pond edge The top edge of the clay lining needs protection from drying out, and from feet or rain eroding it away. So you need the edging materials to hand on the day you puddle your pond so you can protect the edge immediately.

You could use slabs, pebbles, a layer of topsoil or turves (of seed-grown grass, not meadow grass which could contain couch), or even strips of stone-faced edging liner. With these strips, you’d have to anchor the land-side of the strip and if you do this with turves or low-growing plants, ensure some of their roots can tap into soil, otherwise they will die off and the liner edge will be exposed.

Ease of topping up Hot and/or windy weather both cause evaporation, so be sure that you can easily top up the pond from a nearby water source (for example by hosepipe from a tap or rainwater butt).

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How to create a puddled clay pond Once you’ve marked out an outline, it’s time to start digging, taking care not to loosen more soil than necessary. Dig out any shelves from compacted soil – don’t attempt to build them up later from loosened soil because it won’t work.

Having double-checked that the excavation is large enough to accommodate the thickness of clay, begin lining the base with clay. Keep it wet and workable, treading the air out of it as you go. Some people make wooden implements or use the edges of planks to knead the clay with.

Once you’re satisfied that you have a sealed base, move up to the sides, never letting the material dry out. This means you’ll be sloshing around in a footbath, bucketing the water from around your feet to keep the sides wet. Keep going until you reach the lip of the pond, which must be attended to just as diligently. Have your edging material (turves, topsoil, slabs or edging liner) to hand to put in place immediately, and then fill the pond to the top.

You’ll now have an extremely murky pond containing suspended particles of clay. This will take many weeks to settle, and won’t ever settle if the clay sides become exposed, because rain will wash more particles into the water.

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Choosing plants for a puddled clay pond A mixture of floating oxygenators and plants on the shelves and edge of the pond should help the water in the new pond to become balanced.

You’re bound to get the usual pea-soup algal bloom at first, which will go once the excess nutrients are exhausted, but the murk due to suspended clay particles may remain a problem for some while. Be patient, and if the problem doesn’t resolve itself, choose one of the products sold for clearing turbid water.

At the edge of the pond, choose plants that grow in neat clumps (e.g. such as marsh marigolds, Mimulus, water avens, Primula), or spread with a shallow rooting system (e.g. creeping Jenny). Avoid reeds, sedges, watermint, yellow flag, cotton grass, bog bean and other plants that we associate with natural pools and lakes because the roots are invasive and can easily damage the clay lining.

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Maintaining a puddled clay pond Copyright (c) Alec Scaresbrook. Cracked clay means a leaking pond

Copyright (c) Alec Scaresbrook. Cracked clay means a leaking pond

We can’t emphasise enough how important it is to keep the water levels topped up – the photo shows the problems caused by evaporation. As the water level drops, the clay dries out and cracks, so when you do top up the levels, the water just leaks away.

Investigate any sudden water drop and puddle more clay into the leaking area as soon as you can. Otherwise the problem will just get worse, making it more difficult and time-consuming to repair.

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