Can Coll – The Design

Water – catching and storing energy

I believe that if water is present within a property that catching and using it wisely is fundamental to a good permaculture design.  When water enters our system we should hold it in the landscape for the longest time possible, passing it through the greatest area available and using the path of least resistance.  This enables the water to effect the largest number of plants, re-humidify the greatest amount of soil and benefit the most life.

The first step of my design for Can Coll is to redirect the water usage as detailed below;

The plan above shows water entering the property from the river source and filling the tanks used for the household water supply.  This water comes in constantly due to the abundance of water in the valley.  The overflow of these tanks then fills the irrigation IBC via a long pipe.  The IBC then overflows into the duck tank below via an overflow pipe.  This keeps the water constantly moving, collecting nutrient from the duck tank where the ducks swim.  A grate is placed over this duck tank to also allow chickens to walk thus collecting more manurial input.  This water, with it’s new nutrients, then overflows via another pipe to the new wet system below.  It enters tank2 from a height of 2 metres where it gains more oxygen and fertilises the growing system.  Water then leaves tank2 and continues down to the Peace Pond where it provides more nutrient to another growing system  Amanda and Dino with a tranquil place to relax.  From the Peace Pond the water then rejoins the wilderness habitat having performed many more functions.

The next image is the same water flow design but with the additional possibility of adding extra growing mediums in the form of a bathtub or IBC or two or three… as there is an 8m drop in height and approximately 20m is distance between the ducktank and tank2.  Here we can add any number of contained growing mediums for food such as wild rice or fast growing green manures to use as mulch material directly onto the potato field in which they sit.  This new use of water not only utilises a previously unused resource but saves energy filling tanks by hand and adds more humidity to the landscape below, creating wildlife habitat and an interesting place for potential campers.  This adds value to their tourism business and experiential and educational value to campers.

Fig 4 – can coll base map

I have included a revised base map for context as the focus of my design is concentrated on the area around unused tanks.

Fig 3 – Can Coll Forest garden & peace pond

Description of design (not including the wet system within the tanks)

The basis of this design is to utilise the existing resource of water to provide food, medicinal plants, herbs, create wildlife habitat, boost the aesthetics of the area for guests and provide a place of beauty to relax and enjoy.

I have achieved this by making sure that the plants used are edible and medicinal or that they provide a function within the system or that they increase wildlife habitat which in turn makes the whole area more naturally resilient.  Using mostly plants that Amanda and Dino have in excess in other areas of the property I have placed them in a forest garden arrangement as Amanda had expressed some interest in perennial forest gardens.  Plants that enjoy a more moist area have been placed in front of the tanks where it enjoys more water seepage.  Some pruning is needed within the holm oak forest to the south west to allow sufficient light into the area and these logs can then be used to grow mushrooms and structurally for the benches and bridge.

The area utilises the water run off from the tank system to create a beautiful area for relaxation and guests, accessed by a new pathway cut through the bamboo grove.  The peace pond is not only a place to relax but it also provides more food in the form of lotus and trapa and is a haven for frogs who should keep check of unwanted insects.  The whole area is now surrounded with a living willow fence planted from cuttings taken from the old willow in the camping area.  The dappled shade and running water will provide the perfect area for the lookout point to the mountains in front.

Fig1 – Can coll wet system (tank retrofit)

The focus of the design is to make use of two previously unused tanks.  By using natures force to redirect water and a minimal amount of tweaking we now have two unique growing mediums.  Tank1, using the existing spring, adding soil, increasing edge and choosing appropriate plants gives us an edible bog garden.  Tank2, redirecting unused water which now contains added nutrient, sealing the plug hole, allowing the water level to rise, choosing appropriate plants and introducing a protein source has given us new edibles to work with and a unique habitat.  These microclimates are now totally unique and although they will have to find their own balance, by observing and interacting with them they will become rich sources of food and life.

I have chosen all but a few native plants due to the concern of aquatic invasive species.  These should attract beneficial insects, birds and mammals to the system.  We have stacked functions by using vertical space to utilise the wall.  The relative location of this provides more habitat for insects, some of which will perish to become food.  Bat boxes have been added to control possible mozzies and the bat poo will be a useful addition.  Stick piles, burrows, logs and rocks all provide extra habitat.  Nitrogen fixing plants such as azolla should exploit gaps on the water surface which in turn can be scooped out and applied to the forest garden and plants around.

fig2 – can coll tank profile view

aquatic Species Choice

Here you can find details of the plants that I have decided to use.  I have tried to find examples that are native to or have been naturalised in Spain with the exception of a few that I consider worthwhile and which I have found no example of them being too much of a problem.  I have stated as many properties that I know of for each plant demonstrating that they all have multiple uses.  Lots of the information came from the Plants for a Future website and I take no responsibility for any of the edible or medicinal information given.  The following plants are either native or naturalised in Spain (information taken from

Broadleaf Arrowhead or Duck Potato – Sagittaria latifolia

A perennial emergent growing to 1.2m high.  Hardy to -20c and not frost tender. Needs some sun and likes to grow in wet conditions up to 12cm deep.

Edible root raw or cooked. Excellent when roasted, the texture is somewhat like potatoes with a taste like sweet chestnuts. The tubers can be eaten raw but they are rather bitter (especially the skin). It is best to remove this skin after the tubers have been cooked. The tubers can also be dried and ground into a powder, this powder can be used as a gruel or mixed with cereal flours and used to make bread. The N. American Indians would slice the boiled roots into thin sections and then string them on ropes to dry in much the same way as apples. The egg-shaped tubers are 4 – 5cm long and are borne on the ends of slender roots, often 30cm deep in the soil and some distance from the parent plant. The tubers are best harvested in the late summer as the leaves die down. They cannot be harvested by pulling out the plant since the tops break off easily, leaving the tubers in the ground.

Medicinally the poultice of the leaves has been used to stop milk production. A tea made from the roots is used as a digestive.A poultice of the roots is used in the treatment of wounds and sores.  Native or naturalised in Spain.

Duckweed – Lemna minor

A perennial floating spreader hardy to Zone 4 and not frost tender.  Requires a sunny position in still water that is rich in nitrates and lime. Duckweed can be a troublesome pond weed though it is easily controlled by simply scooping it out which makes an excellent addition to the compost heap or as mulch material. The growing plant is a good food source for fish and birds, as well as providing cover for creatures in the pond. It over-winters in temperate areas by means of resting buds which sink to the bottom of the pond in the late autumn and rise again in the spring.  Leaves can be eaten and the whole plant is alterative, antipruritic, antiscorbutic, astringent, depurative, diuretic, febrifuge and soporific. It is used in the treatment of colds, measles, oedema and difficulty in urination. It is applied externally in the treatment of skin diseases and is used as a wash for ophthalmia.  Native or naturalised in Spain.

Azolla –  Azolla filiculoides

A fast growing floating spreader hardy to zone 7 and non frost tender.  This plant fixes nitrogen and is of great benefit to surrounding plants and can also be taken out of the water and used as a rich mulch.  It prefers slow moving water and grows well in semi shade.  It’s used in conjunction with wild rice for it’s nutrient rich biomass but also to block light of other competing plants.  Results have shown that wild rice does very well with azolla.  Native or naturalised in Spain.

Water mint – Mentha aquatica

A marginal edge perennial hardy to zone 6 and non frost tender.  Grows up to 80cm tall and spreads vigorously.  It can grow in the shade and likes full sun and will grow in water up to 15cm deep.  The flowers are especially attractive to bees and butterflies and a good pest confuser and ground cover.  Edible leaves raw or cooked.  A strong distinctive peppermint-like fragrance and used as a flavouring in salads or cooked foods. A herb tea is made from the leaves.  The leaves are anodyne, antiseptic, antispasmodic, astringent, carminative, cholagogue, diaphoretic, emetic, refrigerant, stimulant, stomachic, tonic and vasodilator. A tea made from the leaves has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments. It is also used as a mouth-wash and a gargle for treating sore throats, ulcers, bad breath. The leaves are harvested as the plant comes into flower and can be dried for later use. The essential oil in the leaves is antiseptic, though it is toxic in large doses.  It is also used as a repellent.  Native or naturalised in Spain.

Wild Celery – Apium graveolens

A biennial growing to 0.6m tall, hardy to zone 6 and not frost tender.  It likes moist soil and grows ok in semi shade.  As with all Umbelliferae family it is a great beneficial insect attractor.  Leaves eaten raw or cooked. Mainly used as a flavouring in soups etc. They are toxic if consumed in large amounts. Seed as flavouring. An essential oil from the seed is also used as a flavouring. Root cooked. Wild celery has a long history of medicinal and food use. It is an aromatic bitter tonic herb that reduces blood pressure, relieves indigestion, stimulates the uterus and is anti-inflammatory. The ripe seeds, herb and root are aperient, carminative, diuretic, emmenagogue, galactogogue, nervine, stimulant and tonic. Wild celery is said to be useful in cases of hysteria, promoting restfulness and sleep and diffusing through the system a mild sustaining influence. The herb should not be prescribed for pregnant women. Seeds purchased for cultivation purposes are often dressed with a fungicide, they should not be used for medicinal purposes. The root is harvested in the autumn and can be used fresh or dried. The whole plant is harvested when fruiting and is usually liquidized to extract the juice. The seeds are harvested as they ripen and are dried for later use. An essential oil obtained from the plant has a calming effect on the central nervous system. Some of its constituents have antispasmodic, sedative and anticonvulsant actions. It has been shown to be of value in treating high blood pressure. A homeopathic remedy is made from the herb used in treating rheumatism and kidney complaints.  Native or naturalised in Spain.

Mitsuba or Japanese Parsley – Cryptotaenia japonica

An evergreen perennial growing up to 1m tall>  It likes a moist soil and can be grown in boggy conditions.  It’s very shade tolerant and can grow in full shade.  This plant is loved by slugs and although edible it can be used as a frog attractor and duck forage.  As a Umbelliferae family member it attracts a host of beneficial insects too.  Edible Leaves and stems raw or cooked. Used as a flavouring with a parsley-like flavour. Seedlings and young leaves can be used in salads. When cooking, the leaves should not be cooked for more than a couple of minutes or the flavour is destroyed. The leaves contain about 2.3% protein, 0.23% fat, 4.4% carbohydrate, 2.1% ash. Blanched stem – a celery substitute. The seed is used as a seasoning.  Medicinally used for women’s complaints. Used in the treatment of haemorrhages, colds, fevers etc. Used as a tonic for strengthening the body.  Native or naturalised in Spain.

 Hardy Passionfruit – Passiflora caerulea

A delicious edible evergreen climber hardy to zone 7 and non frost tender.  It likes a moist soil and needs some sun.  Chosen as a trellis plant on the back of the two tanks for it’s fruit, bee forage flowers and fast growing habit.  Unripe fruits can be cooked and fresh fruit can be eaten raw or made into a refreshing drink.  It seems that long hot summers are needed for good fruit which may be ideal in the Pyrenean’s sunny climate.  Using vertical space like a trellis above the bog garden and crayfish tank makes use of a space that it under utilised.  Birds are attracted as well as bees and insects who drop manure into the systems below.  The wall and the water below also create a beneficial mircoclimate where the fruit above can hopefully flourish.  It will also serve as a mini wildlife corridor connecting the wet area below to the higher area and trees above.  Native or naturalised in Spain.

Tiger Nut or Chufa – Cyperus esculentus

A perennial growing in wet boggy soil to 80cm and hardy to zone 8 but I would like to try in a protected environment as it has proved more hardy than originally thought.  Grown commercially in spain and actually a tuber rather than a nut.  It was first discovered 4000 years ago and comes in several sizes. Tigernuts have long been recognised for their health benefits, as they are high in fibre, proteins, and natural sugars.  Tuber eaten raw, cooked or dried and ground into a powder. They are also used in confectionery. A delicious nut-like flavour but rather chewy and with a tough skin. They taste best when dried. They can be cooked in barley water to give them a sweet flavour and then be used as a dessert nut. A refreshing beverage is made by mixing the ground tubers with water, cinnamon, sugar, vanilla and ice. The ground up tuber can also be made into a plant milk with water, wheat and sugar. An edible oil is obtained from the tuber. It is considered to be a superior oil that compares favourably with olive oil. The roasted tubers are a coffee substitute. The base of the plant can be used in salads.  Tiger nuts are regarded as a digestive tonic, having a heating and drying effect on the digestive system and alleviating flatulence. They also promote urine production and menstruation. The tubers are said to be aphrodisiac, carminative, diuretic, emmenagogue, stimulant and tonic. In Ayurvedic medicine they are used in the treatment of flatulence, indigestion, colic, diarrhoea, dysentery, debility and excessive thirst.  The tubers contain up to 30% of a non-drying oil, it is used in cooking and in making soap. It does not solidify at 0°c and stores well without going rancid. The leaves can be used for weaving hats and matting etc.  Native or naturalised in Spain.

Polypody – Polypodium vulgare

An evergreen fern growing one foot high in deep shadey moist areas.  Rich in potash, it creates an excellent ground cover.  The Root. Very sweet, it contains sugars, tannin and oils. It is used as a liquorice adulterant. The root has a unique, rather unpleasant odour and a sweet (cloying) flavour at first though it quickly becomes nauseating. The root contains 15.5% saccharose and 4.2% glucose.  Used medicinally Polypody stimulates bile secretion and is a gentle laxative. In European herbal medicine it is traditionally used as a treatment for hepatitis and jaundice and as a remedy for indigestion and loss of appetite. It should not be used externally since it can cause skin rashes. The root is alterative, anthelmintic, cholagogue, demulcent, diuretic, expectorant, pectoral, purgative, tonic. It can be used either fresh or dried and is best harvested in October or November, though it can be collected until February. The leaves can also be used but are less active. A tea made from the roots is used in the treatment of pleurisy, hives, sore throats and stomach aches and as a mild laxative for children. It was also considered of value for lung ailments and liver diseases. The poulticed root is applied to inflammations. A tea or syrup of the whole plant is anthelmintic.  Native or naturalised in Spain.

Water Milfoil – Myriophyllum spicatum

A perennial rooted floater,  spreading and used as an oxygenator.  It’s hardy to zone 6 and the buds overwinter in the bottom of water.  Edible roots and used medicinally too.  Main use is oxygenation and wildlife habitat.  Native or naturalised in Spain.

Myriad Leaf – Myriophyllum verticillatum

A perennial rooted floater,  spreading and used as an oxygenator.  It’s hardy to zone 3 and the buds overwinter in the bottom of water.  Edible roots and used medicinally too.  Main use is oxygenation and wildlife habitat.  Native or naturalised in Spain.

Golden Saxifrage – Chrysosplenium oppositifolium and Chrysosplenium alternifolium

A low growing perennial liking semi shade and moist or wet but well drained soil.  It’s hardy to zone 5 and is pollinated by flies and beetles.  Edible leaves raw or cooked used in salads and soups.  It’s creeping habit makes it a good ground cover and wildlife refuge in a bog garden.  Native or naturalised in Spain.

Flowering Rush – Butomus umbellatus

A clumping emergent perennial hardy to zone 5 and growing up to 1m tall.  It needs sun and grows in wet soil and water up to 30cm deep.  A great bee, fly and lepidoptera attractor.  Edible tuber cooked. It should be peeled and the rootlets removed. The root can also be dried and ground into a powder, it can then be used as a thickener in soups etc, or be added to cereal flours when making bread. It contains more than 50% starch.  Native or naturalised in Spain.

Pennywort – Hydrocotyle vulgaris

A marginal spreading perennial ground cover hardy to zone 6 and not frost tender.  Likes partial shade and is a beneficial insect attractor with edible leaves cooked tastes like carrot but should not be consumed in large quantities.  Native or naturalised in Spain.

Friar’s Cowl – Arisarum vulgare

A perennial growing in full shade hardy to zone 7 and non frost tender.  It likes a moist soil with a leafy mulch (forest floor).  Used as a ground cover for shady places and insect attractor.  Edible root – cooked. The acrid juice should first be removed by thorough and repeated washing leaving behind a nutritious and innoxious residue. Thorough drying or cooking will also destroy any harmful elements of this root. The root is frequently used as an emergency food in times of scarcity, it is about the size of a walnut. One report suggests that the leaves might be edible. If they are they must be well cooked first.  Native or naturalised in Spain.

Galingale – Cyperus longus

An evergreen clumping emergent perennial growing up to 1m high and hardy to zone 7.  It needs half sun and wet soil and likes to grow in water up to 30cm deep. Edible tuber used as a spice in soups, pies and sweets. Galingale was one of the favourite spices of the medieval kitchen and was an ingredient of ‘pokerounce’, a kind of medieval cinnamon toast.  The leaves are used in basketry and for weaving hats, matting etc. The root and stem have the scent of violets and are used in perfumery. The aroma becomes more pronounced when the root has been dried and left to age. A fibre obtained from the plant is used in paper making.  A great looking plant and good wildlife attractor.  Native or naturalised in Spain.

Native Watercress – Sisymbrium crassifolium

A perennial growing to 60cm liking wet soils with semi shade.  Edible leaves and young stems – cooked have a cabbage-like flavour.  Native or naturalised in Spain.

Bulrush or Wood Clubrush – Scirpus sylvaticus 

A clumping emergent perennial hardy to zone 7 and non frost tender. Grows well in boggy clay soil and also likes shallow waters.  Known to be a very beneficial wildlife plant.  Edible root  raw or cooked. Rich in starch.  The sweet roots are eaten raw in mid summer. The bruised young roots, when boiled in water, furnish a sweet syrup. The rhizomes are 3 – 10mm in diameter. Young shoots cooked. The tender base of the stem is eaten raw in salads. The pollen is used in soups or mixed with flour and used in making bread. It is rich in protein. The root is astringent and diuretic. The stem pith is haemostatic. A poultice of the stem pith has been placed under a dressing in order to stop wounds bleeding. he stems are used in weaving and basket making. They are used to make good quality mats for use on the floor, for sleeping on and for making temporary partitions. The stems are pulled off the plant rather than cut to ensure the maximum length of stem.  This plant is also used as a bank stabiliser and water purifier.

Small Reed Mace – Typha angustifolia

An emergent perennial growing up to 3m tall and hardy to zone 3.  It likes some sun and grows in wet soil but preferable water up to 15cm deep.  Particularly noted for attracting wildlife including dragonflies and birds.  Has millions of good reasons to grow it apart from that it takes over small areas.  I am just including it here for information.  Read more


The following plants are not native to Spain although they may be found in the country already.  I consider these plants of useful benefit to the system but would welcome any feedback on their invasiveness.

 Watercress – Nasturtium officinale

A perennial marginal spreader hardy to zone 6 and not frost tender.  It likes clean slow moving water of about 5cm deep particularly limestone.  It needs some sun.  It’s noted as a wildlife attractor and bee forage plant as it has a rich source of pollen. Edible leaves raw or cooked. Water cress is mainly used as a garnish or as an addition to salads, the flavour is strong with a characteristic hotness. It has a reputation as a spring tonic, and this is its main season of use, though it can be harvested for most of the year and can give 10 pickings annually. The leaves are exceptionally rich in vitamins and minerals, especially iron. The seed can be sprouted and eaten in salads. A hot mustardy flavour. The seed is ground into a powder and used as a mustard. The pungency of mustard develops when cold water is added to the ground-up seed – an enzyme (myrosin) acts on a glycoside (sinigrin) to produce a sulphur compound. The reaction takes 10 – 15 minutes. Mixing with hot water or vinegar, or adding salt, inhibits the enzyme and produces a mild but bitter mustard.  Watercress is very rich in vitamins and minerals, and has long been valued as a food and medicinal plant. Considered a cleansing herb, its high content of vitamin C makes it a remedy that is particularly valuable for chronic illnesses. The leaves are antiscorbutic, depurative, diuretic, expectorant, purgative, hypoglycaemic, odontalgic, stimulant and stomachic. The plant has been used as a specific in the treatment of TB. The freshly pressed juice has been used internally and externally in the treatment of chest and kidney complaints, chronic irritations and inflammations of the skin etc. Applied externally, it has a long-standing reputation as an effective hair tonic, helping to promote the growth of thick hair. A poultice of the leaves is said to be an effective treatment for healing glandular tumours or lymphatic swellings. Some caution is advised, excessive use of the plant can lead to stomach upsets.

American Water Lotus – Nelumbo lutea

A rooted floating perennial hardy to zone 4 and loved by bees and people. It needs sun and likes to be in water up to 0.6m deep.  Edible root cooked. It is usually steeped in water prior to cooking in order to remove any bitterness. The root is rich in starch when baked it becomes sweet and mealy, somewhat like a sweet potato. The root is usually harvested in the autumn and will store for several months. Leaves and young stems cooked. Seed raw or cooked. A very agreeable taste. The seed can be dried, ground into a powder and used for making bread, thickening soups etc or can be eaten dry. The bitter tasting embryo is often removed. The half-ripe seed is said to be delicious raw or cooked, with a taste like chestnuts. The seed contains up to 19% protein. An edible oil can be extracted from the seed.

Fragrant Water Lily – Nymphaea odorata

A spreading perennial hardy to zone 5.  Enjoys plenty of sun and known to attract beneficial insects and wildlife.  It likes water at least 30cm deep.  Edible Flower buds cooked as a vegetable or pickled. Young flowers eaten raw. Leaves eaten raw or cooked. Used in soups and stews. Root boiled or roasted. Ripe seed  cooked or ground into a meal. The root is alterative, anodyne, antiseptic, astringent and demulcent. A tea made from the roots is used in the treatment of TB, chronic bronchial complaints, diarrhoea, dysentery, gastrointestinal inflammation, gonorrhoea, vaginal discharge, inflamed glands, mouth sores and to stop bleeding. A poultice made from the roots is used in the treatment of swellings, boils, tumours, inflamed skin, vaginitis etc. The roots are harvested in the autumn once the plant has died down, and are dried for later use. A complete cure of uterine cancer by a decoction and uterine injection has been recorded. A very ornamental plant, the sweetly fragrant flowers are 12cm in diameter. The flowers open in the morning, when they are at their most fragrant, and close in the afternoon.  Great for relaxing areas.

Trapa natans – Water Chestnut

A perennial rooted floater hardy to zone 5.  A water plant, growing in water up to 60cm deep. Requires a sunny position in slightly acidic water. Dislikes calcium rich water.  Edible seed raw, cooked or dried and ground into a powder. A sweet floury and agreeable flavour, similar to sweet chestnuts.  I think this should be grown as an annual and harvested and then replanted the following year.  Very tasty.  This plant is considered to be an invasive species in some areas but I believe that if it is contained with the tank that it should not be a problem.

Ideas for Implementation on the next page

One response to “Can Coll – The Design

  1. appletonpermaculture

    Wow! What a great resource! I almost can’t resist just grabbing a spade a digging a pond 😀

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