Drought tolerant plants

Red Hot Poker flowers in the garden with sunlight

Drought tolerant plants look good and are low maintenance
Image: Peter Betts

There are lots of good reasons to grow drought tolerant plants. During hot summers the need for frequent watering is time consuming. Not to mention costly to the environment and your pocket too, should rainfall in your area fail to keep up with demand.

We asked The Sunday Gardener, Carol Bartlett, her advice on drought tolerant plants. Here are some of her all time favourites, some of which positively thrive on neglect…

Why choose drought tolerant plants?

Lavender 'Hidcote' from Thompson & Morgan

Aromatic and easy to grow, lavender is loved by pollinators
Image: Lavender ‘Hidcote’ from Thompson & Morgan

Some areas of the country are significantly drier than others. Parts of the south-east like Essex, Kent and Cambridgeshire receive as little as as 513mm of rainfall per annum. Last year, Bury St Edmunds in Suffolk recorded 49 consecutive days without rain.

London is another area of very low rainfall. The capital gets around 557mm per annum – less than Miami and Florida. In these drier parts of the UK, successful gardening is very much a case of “right plant, right place.”

Water is a precious resource, and going forward we need to continue to find ways to conserve it. Incorporating drought tolerant plants into our gardens is an important step towards helping the environment.

The good news? There are some fantastic drought tolerant plants which rarely get thirsty, require very little time and attention, and bring show-stopping structure, scent and colour to your beds and borders. Here are some of the easiest to grow.

Silver and grey leaved plants

silver/green leaves of Artemisia 'Valerie Finnis' against Nepeta 'Six Hills Giant'

Artemisia ‘Valerie Finnis’ looks beautiful against Nepeta ‘Six Hills Giant’
Image: Royal Botanic Garden Edinburgh

This group includes many of my garden favourites and these plants look great when planted together. Lavender is particularly suitable for dry ground, and there are many stylish varieties that work well as a low hedge along a path, releasing their scent as you brush past.

The shrub Artemisia has finely divided silver leaves which are also aromatic. Illustrated is Artemisia ‘valerie finnis’ whose pale silver foliage makes a fantastic combination alongside the blue flowers of Nepeta.

Perovskia, commonly known as Russian sage, has grey/green leaves and masses of spires of soft blue flowers, which the bees love. It’s a small aromatic shrub that’s easy to grow in dry conditions. Perovskia requires pruning in late April/early May. This is to keep the growth compact, cutting back to a small framework of just a few inches. It’s important not to cut the woody parts which don’t have buds, which is why pruning is often delayed until the buds appear as a guide.

Stachys Byzantina, also known as lambs ears, probably has the softest, most downy, silver leaves of any plant and is totally irresistible to the touch! Spires of grey leaves produce small mauve flowers from late June onwards. These insignificant flowers are a bee magnet – attracting bumble bees and female wool carder bees who harvest hairs from the plant’s leaves to make a nest.

The Salvia family is easy to grow in dry areas and this includes common sage, an attractive, small evergreen shrub useful for culinary purposes. Amongst the more colourful flowering varieties are Salvia x sylvestris ‘Viola Klose’ a strong violet blue; and the popular two-toned Salvia ‘lips collection’ – ‘Amethyst Lips’, ‘Hot Lips’ and ‘Cherry Lips’.

Drought resistant shrubs are a good way to provide structure and all year round interest in your planting scheme. Mediterranean shrubs like Rosemary and Santolina are ideal, as is the sun-loving Cistus which grows wild in many areas of the Med where it bakes happily in the sun. Buddleia is ideal in a dry sunny spot with the added benefit of being attractive to pollinators and butterflies. If you don’t have space for a large shrub, there are now more compact buddleia varieties too.

Drought resistant garden favourites

Colourful drought tolerant border photographed in Oxford by The Sunday Gardener

A striking drought tolerant border in Oxford
Image: The Sunday Gardener

Creating a drought resistant border doesn’t mean settling for something dull. Amongst the group of drought tolerant plants there are some real show stoppers, such as Agapanthus. The striking blue flowers of agapanthus are always eye catching and combine beautifully with the terracotta shades of Achillea, which are also drought tolerant.

Many of my favourite perennials also happen to prefer dry soil:

Even taller, growing up to around 60cms, and a definite garden favourite is Verbena bonariensis with clusters of tiny purple flowers which are attractive to bees and butterflies. It’s not fully hardy all over the UK, but helpfully self-seeds to create new plants for next year. A mulch will help it through the winter.

This perfect drought tolerant planting combination was spotted in Oxford: Verbena bonariensis, sedum, mauve flowering asters and the grass Pennisetum, all of which will tolerate a prolonged dry spell.

Best drought resistant bedding plants

Vinca Major 'Maculata' from Thompson & Morgan

Hardy periwinkle can thrive in almost any soil, even dry shade
Image: Vinca Major ‘Maculata’ from Thompson & Morgan

Late spring is the best time to fill gaps in your borders with bedding plants and brighten up summer containers. Some bedding plants are better suited to drier areas than others, although container plants will always require watering, simply because of the growing environment.

Pelargoniums, also known as geraniums, tolerate a great deal of heat and dust. Think of holidays abroad when you see geraniums tumbling from balconies in the hot Mediterranean sun – they love it! Similarly, Gazania and Mesembryanthemum (Ice Plants) like it hot, dry and sunny, not least because they belong to a group of plants whose flowers close when the sun sets, or on cloudy days. Closing their blooms helps to conserve moisture.

Additional bedding plants for dry containers are Argyranthemum (Marguerite) and Osteospermum, both of which have daisy-like flowers. Nicotiana, dahlia, and the lovely muted tones of salvia ‘seascape’ also make good container plants.

Is it a shrub, or is it ground cover? Vinca major, (also known as periwinkle) with its attractive mauve flowers, is drought tolerant. In this combination periwinkle has been planted with ivy, which is very resistant to drought, to make a container display which will thrive on neglect. Alternatively, the 2019 Chelsea Flower Show’s ‘Plant of the Year’ first prize winner, Sedum ‘Atlantis’ is happy as ground cover and in containers. It’s also very popular with pollinators.

How to look after plants in a drought

Even drought-resistant plants will sometimes show signs of stress, and watering may become necessary.

For more efficient watering, check plants individually by testing the surrounding soil to see how dry it is. Some plants will need more water than others. Always apply water to the roots, and in the evening, when less will evaporate. Finally, applying a mulch also works wonders: it conserves water, reduces weeding and improves the look of borders.

 

Good companions in the veg plot

late summer vegetable garden with full rows and flowers in bloom

Plant vegetables, herbs and flowers together for optimum results
Image source: Irina Fischer

Companion planting is the art of growing different plants together to achieve certain benefits, such as helping with pest control, encouraging pollination or increasing crop yields. With a little thought, companion planting can also create a feast for the eyes, turning a functional veg plot to a glorious thing of colour and beauty.

We asked The Sunday Gardener, Carol Bartlett, for her advice on companion planting. Here are some of her top tips…

What is companion planting?

RHS Kitchen Garden at Harlow Carr

RHS Kitchen Garden at Harlow Carr
Image credit: Lee Beel

Companion planting has long historical roots, harking back to a time when there were no chemicals to control pests or to feed plants, and gardeners relied purely on nature. In the 1970s, when organic gardening became popular once again, companion planting enjoyed a renaissance which continues to this day.

But there’s another aspect to companion planting which is equally popular: using contrasting plants and vegetables to create an aesthetically appealing kitchen garden. This style of planting is illustrated above, in this RHS garden at Harlow Carr where the veg plot looks immaculate and is full of colour. In and amongst the vegetables are sweet peas, nasturtiums, tagetes and lavender, creating a veg plot that’s both beautiful and productive.

It’s fair to say that recent studies have been less than conclusive about the direct benefits of companion planting. I view it as a way to deter pests while also making my vegetable plot more attractive. In this wider context, which includes the aesthetic look of the veg plot, perhaps it’s less important to measure the direct benefits scientifically.

How companion planting works: repel and sacrifice

Closeup of orange nasturtiums and yellow chard

The combination of orange nasturtiums and yellow chard is both beautiful and strategic
Image source: Peter Turner Photography

There are two types of companion plants: some are grown because their smell repels unwanted insects, and others are grown as a sacrifice to keep the main crop insect-free.

One of the best known combinations recently receiving tentative scientific approval is planting tomatoes together with French Marigold (Tagetes patula) to reduce whitefly. Marigolds contain a substance called limonene, and scientific data confirms that tomatoes grown alongside limonene suffer less from whitefly. It’s also true that tomatoes and tagetes make a colourful planting combination!

Another good companion for tomato plants is basil. They look and taste good together, and this scented herb is said to repel pests.

Plagued by aphids? Nasturtiums make good aphid traps. The flowers secrete mustard oil which lures the insects away from brassicas and other crops. In a similar vein, some people use French marigolds as slug bait – meaning they’re used as sacrifice plants to keep your lettuce free from slugs.

Strong smelling plants, such as lavender, mint and sage are reputed to confuse and repel aphids and other unwanted insects away from many vegetables, including carrots. The combination of alliums and carrots is often recommended, but given the tenacity of the carrot fly, I personally always use a physical barrier as well. I’m happy to plant alliums and chives around my carrots, but put my faith in a sturdy barrier!

Companion planting to attract pollinators

Closeup of purple borage from the RHS

Borage is a beautiful, pollinator-friendly herb
Image source: RHS

We’re becoming ever more aware of the vital role of pollinators and bees to our food culture. Carefully chosen companion plants definitely help to attract pollinators to your vegetable plot, and the more pollination, the better the yield.

The English pot marigold, Calendula, is so easy to cultivate that it almost grows itself. Unlike the French marigold it’s of no interest to slugs, who ignore it, but pollinators like hoverflies, lacewings and ladybirds are incredibly attracted to its lovely zingy yellows and oranges. What’s more, Calendula will seed itself from year to year with no gardening attention whatsoever.

Want to increase your tomato yields? Encourage more bumble bees. In fact, bees are so essential to tomatoes that boxes of them are often imported into commercial greenhouses to work their pollinating magic. In your own greenhouse, chives are one of the best ways to attract bees and are ideal planted with tomatoes. A few pots of chives near the entrance and around your plants will welcome them in!

Another herb that’s a great friend of pollinators is borage, with its lovely delicate flowers that attract bees, butterflies, and hoverflies. But if I could grow just one plant to attract pollinators it would be oregano, beloved of all pollinating insects.

For more information about companion planting combinations, see the chart in our Companion Planting Guide. Know of any combinations we haven’t mentioned? Please leave us a comment and share your tips.

 

Starting a culinary herb garden

closeup of hands taking cuttings of basil from a white windowsill box

Grow herbs to add to your garden and kitchen.
Image: DarwelShots

Anyone can start a herb garden, no matter how little space they have available. Some people create bespoke culinary herb gardens, while others tuck these flavour-packed plants into any empty space they can find.

We asked The Sunday Gardener, Carol Bartlett, for her top tips on growing herbs at home. Here’s her sage advice…

What is a herb?

collection of harvested herbs on a brown cutting board

Grow hardy herbs in shady spots.
Image: Shutterstock

‘Herb’ is a generic term. It covers a wide group of plants that don’t necessarily share the same preferences for growing conditions. It’s true to say that, as a group, herbs mostly prefer sun – especially those of Mediterranean origin. But for those of us who don’t have sunny, south-facing gardens, there are enough herbs that tolerate semi-shade to keep a keen cook happy.

Should you grow herbs from seeds or plants?

Pots of Rosemary, Thyme, Mint and Coriander on a windowsill

Start with plug plants for faster results.
Image: Christine Bird

Many herbs germinate readily from seed – an easy and inexpensive way to get started. Early in the year (before May), it’s best to sow on a windowsill or under glass. Simply place several seeds in a small plant pot, and cover with a light sprinkling of soil. Keep the soil warm and ensure you keep it moist.

From May onwards you can sow herb seeds directly outdoors into containers or your veg plot. It’s best to sow crops like parsley and coriander fortnightly, to ensure a regular supply. If you want to grow from seed, I suggest parsley, coriander, chives and basil – you’ll need a regular succession of these plants to keep your kitchen in business.

If you don’t have time to grow from seed, there’s a wide variety of herbs available to buy as plants for an instant, ready-made herb garden. It makes more sense to buy herb plants if you only need a few of each. I suggest buying mint, oregano, sage, rosemary, thyme and lemon balm this way to get started.

Where to plant Mediterranean herbs

Sage (Salvia officinalis) from Thompson & Morgan

Fully-hardy sage thrives outside
Image: Sage from Thompson & Morgan

Sun-loving Mediterranean herbs include thyme, rosemary, oregano and sage. They need to be planted in dry, well-drained soil and get plenty of sun to grow well. Some of them, like thyme and oregano are particularly attractive to bees and pollinators – ideal if you’re trying to attract more wildlife into your garden.

Thyme:

Different varieties of thyme are available with small, pretty flowers in white, mauve and pink. These plants look attractive in containers, and they also like to grow in small crevices in walls and paving. Because of its compact size, thyme is ideal for growing on a windowsill. It’s easy to grow and requires little maintenance except for a light trim after flowering. For culinary use, I consider Thymus Vulgaris (common Thyme) best. It has a lovely aromatic sweet flavour and easy to pick leaves.

Rosemary:

Rosemary is a larger plant that grows to somewhere between 60 cms and 1m, but it’s relatively slow growing. It’s reasonably hardy, but less so in poorly drained soils and it dislikes cold, chilling winds. If conditions aren’t ideal, there’s a tendency for the needles to brown.

The other common variety of rosemary, from the prostrate group, is not fully hardy and requires winter protection. As the name suggests, this is a trailing plant which is best grown in a container so that you can move it under glass for winter protection.

Sage:

Sage is fully hardy and happily grows outside all year round. It can look a bit battered at the beginning of the growing season but quickly picks up. Both sage and oregano do get quite large as they mature, up to around 60cms tall with an equal spread.

Oregano:

Oregano is a fully hardy perennial that benefits from being cut back in the spring.

One oregano shrub usually provides enough pickings for a family, but I always grow more to feed the wildlife. Origanum vulgare is an attractive shrub which has pretty mauve flowers that bees and butterflies just love. Mine are covered all summer with busy pollinators. Many herbs are attractive to bees and butterflies, but oregano is one of the best.

Which herbs grow in semi-shade?

Basil 'Siam Queen' from Thompson & Morgan

Grow basil on window sills if you have limited outdoor space.
Image: Basil ‘Siam Queen’ from Thompson & Morgan

Don’t have a south-facing garden? A number of culinary herbs tolerate semi-shadeparticularly chives, parsley, mint, lemon balm and coriander. As long as they’re in the sun for at least half a day (preferably morning), these herbs don’t mind living without full sun.

Chives:

Chives are very hardy – they die back over winter and regrow in the spring. They’re also another bee magnet if you want to attract wildlife into your garden.

Parsley:

This herb can be slow to germinate, but once it gets going it’s pretty tough. Planted outside, parsley produces good pickings well into the winter and tolerates frosts, and although biennial, it should be treated as an annual.

Of the various herbs discussed here, parsley is the only one which can be difficult to germinate from seed. Patience and more than one sowing may be necessary, but once established, it’s robust and hardy.

Mint:

There’s a gardening ‘health warning’ attached to mint because it’s so invasive. If you want to plant mint in a border, it must be contained to prevent it from taking over, (and the same is true of tansy should you have an urge to plant it.) It’s much better to grow mint in a container to restrict its spread. A perennial plant, it’s often treated as an annual because the leaves become coarse with age.

Coriander:

Coriander grows as an annual in our climate. Because it resents transplanting, sow the seeds where you want them to grow and take care that the plants don’t dry out. Fortnightly sowing is best to provide a regular supply for your favourite recipes – and it’s best to pick the leaves before flowering.

Basil:

One of the more tricky herbs to grow in our climate is basil, despite the fact that it always looks so tempting in supermarket pots! Basil is easy to grow from seed and germinates quickly. The drawback is that it’s very temperature sensitive. It should never be placed outside until the summer is in full swing and then only in a warm sheltered spot. If it’s too cool, the plant leaves tend to yellow, and develop unappealing beige patches. Conversely, basil is ideal to grow indoors and perfect for your windowsills.

Even more tempting, and requiring the same growing conditions, Thai basil is a fantastic addition to authentic curries. Thai basil germinates easily from seed when placed in a warm spot with good drainage. It will do well all summer, but later in the year both Thai and Italian basil should be brought indoors to extend the growing season.

Growing your own herbs makes an aromatic garden display, attracts lots of bees and butterflies to your garden and gives you a wonderful fresh supply of herbs for the kitchen all the year round. What’s more, you can pick them at their best and freeze any excess if you find you have too much. Happy herb growing!

 

How to store home grown vegetables

Make the most of your home grown veg by storing it correctly
Image source: Shutterstock

There is plenty to harvest from the vegetable plot, and if you have a glut it might not be possible to eat them all at once. To enjoy vegetables throughout autumn and winter it’s vital to store them correctly. Here’s our simple guide to storing your home grown vegetables.

Keep vegetables fresher for longer

Separate bad veg to enjoy the ‘fresh from the garden’ taste for longer
Image source: Zaretskaya Svetlana

It’s important that no damaged or rotting vegetables are put into storage. Over time, damaged fruit or veg will infect any vegetables nearby, causing them to rot. This bears out the old adage ‘a bad apple spoils the bunch.’ There’s no need to waste damaged produce – if you have vegetables which are less than perfect, simply set them aside to use first.

Only place completely dry vegetables in storage. It’s best not to wash vegetables with water before they are stored. Instead, any excess dirt should be gently brushed off. Cut off any top growth from root vegetables before storage.

These general rules apply to all veg, but different vegetables dictate different methods of storage. For example, two of our favourite crops, onions and potatoes, are as different as chalk and cheese when it comes to the best methods of storing them.

How to store potatoes

Potatoes must be kept away from light
Image source: Shutterstock

It is crucial that potatoes are stored in a dark, and ideally cool place. Light causes potatoes to produce chlorophyll, which produces solanine, a natural toxin present in green potatoes which causes an upset stomach. You mustn’t eat green potatoes.

Once the potatoes have been lifted, they should be cleaned of soil and only put into storage once dry. A good storage area for potatoes – and a number of other vegetables – is in a garage because it’s a cool, frost-free space.

Potatoes store well in hessian sacks, or if these are not to hand, a box or potato sacks can be used with layers of newspaper to exclude all light and to ensure that the tubers remain dry. An ideal storage combination would be hessian or potato sacks inside a container that excludes light, left slightly open to allow air circulation.

Like many root crops, potatoes need to be kept cool. Greenhouses and conservatories are not recommended, as they tend to be too light.

Storing alliums: leeks, onions and garlic

Plaiting garlic and onions is a practical and attractive storage method
Image source: Mattis Kaminer

Onions and garlic need to be kept dry and stored in the light. Traditionally, onions are lifted and left resting on the soil for a few days to dry, which is all very well if your harvest coincides with a dry spell. Since our weather is often capricious, it’s best to lay out onions and garlic to dry indoors or under glass. This usually takes up to a week.

Onions and garlic can be strung together or woven into decorative plaits and stored. Once the top growth has dried out it will plait easily. Start with the large onions or garlic bulbs and plait in descending size ending with the smallest. If there is not enough top growth, weave in raffia to make more to plait with.

Although onion plaits and strings look decorative in the kitchen, it’s not an ideal storage area as it can be humid. Onions and garlic are best stored in a cool, dry environment such as a porch, conservatory, or greenhouse. Onions and garlic can also be stored in string bags or nets.

Leeks, although members of the Allium family, are different again. Leeks are best left in the ground over winter and dug up as and when required. Traditional varieties such as ‘Musselburgh’ will withstand winter and can be harvested from December to March.

Parsnips are another crop which can be left in the ground until needed, and their flavour is reputed to be better after hard frost.

Not so for carrot and beetroots, which need to be lifted in autumn before the weather turns wet and cold. There are traditional methods for storing root crops in sand and compost, but it is easier to put them in hessian sacks or string nets, and store in a cool dark place.

Turnips and Swede can be left in the ground but if your plot is wet, (and also bearing in mind the difficulties of lifting vegetables from frozen ground), both crops can be lifted and stored in the same way.

Storing peas and beans

Enjoy your petit pois for longer by freezing a glut
Image source: Thompson & Morgan

In the centuries up to our modern times, large estate houses had areas of cellars and rooms dedicated for storage to feed the family and estate workers through the winter. Today, we have freezers. Freezing is the only way to store French, runner, and broad beans, and peas including varieties such as mange tout.

These vegetables need to be prepared and blanched in boiling water for two minutes. After two minutes, drain and plunge them into ice cold water to stop them from cooking any further, and bag up into the freezer. This way you can enjoy your home-grown peas or beans with Sunday lunch for weeks to come.

How to ripen green tomatoes

Ripen green tomatoes indoors if it’s getting too cold
Image source: Thompson & Morgan

Tomatoes, especially when in the greenhouse, will keep ripening until late in the season depending on the autumn weather. If you have a glut of green tomatoes at the end of the growing season, there is no need to resort to green chutney. Tomatoes will ripen indoors and be perfectly edible.

Cut good sized tomatoes on the vine as soon as the temperature begins to cool and bring indoors into the warm. Make sure the fruits you put out to ripen are all without blemish and in good condition. Lay out the vines on newspaper, ideally in a conservatory or on a warm south facing windowsill. The majority will continue to ripen over October and early November.

Whatever type of crop you are storing over winter, it is a good idea to check on them from time to time. Remove any damaged vegetables to ensure they continue to store well.

How green is your pond?

frog-on-leafpad-pond

Ponds are great way to attract wildlife to your garden.
Image source: Svetlana Foote

A pond will attract a variety of wildlife into the garden such as frogs, damselflies, dragonflies, water boatman and pond skaters. Many different types of birds will visit for a bath and a dip; I even had a kingfisher dive in for a fish.

But what should you do if your pond looks like a bowl of green soup? The good news is that this can be fixed. Here’s how.

A natural water balance

Don’t despair if your pond looks like pea soup.
Image source: Carol Bartlett

The cause of this greening is algae. Usually a pond is fairly clear over winter until spring arrives and the ecology starts to change. As temperature and sunlight levels increase, the water warms up, blooms of algae appear, and your pond turns green.

For algae to thrive in your pond it needs sun, minerals and nutrients to feed on. The key to maintaining clear water is to create an ecological balance which reduces these elements, in turn, inhibiting the algae.

Reduce sunlight to the pond

Use plants to reduce the amount of sunlight that reaches the water.
Image source: Dirk Ott 

Cutting down the amount of sun on your pond will make the conditions less suitable for algae. This may seem counterintuitive since most pond plants like a good amount of sun. So to keep algae in check you’ll need to come up with a clever way to reduce the amount of sunlight to the water without shading the plants.

The answer is to cover a good part of the pond’s surface with plants that will act as a shield to the water underneath. Floating plants, submerged plants and water lilies are ideal. You should aim to cover about half of the pond’s surface.

Reduce nutrients in the pond

Scoop any fallen leaves from your pond to reduce nutrients in the water.
Image source: Sinica Kover

Algae feed on the nutrients in your pond, so reducing nutrients in the water will inhibit algae growth. Avoid constructing a pond near deciduous trees and shrubs. When leaves fall into a pond they sink to the bottom, rot down and make the water more nutrient rich. In addition they also release toxins which pollute the water and endanger pond life. If leaves do fall into the pond, it’s best to skim them off with a net and remove.

It may be tempting to use ordinary compost when planting into a pond, but it’s full of nutrients. It’s better to use sterile aquatic compost which is free from peat and nutrients wherever possible.

There is also the thorny issue of whether to introduce fish. Fish are attractive, but they excrete, which adds nutrients to the pond and feeds the algae.

Oxygenate the water

Water Crowfoot is a good oxygenating plant.
Image source: Zoltan Major

Algae grows fast and can rapidly deplete the water of oxygen. It’s important to oxygenate the water to support the plants and wildlife which in turn keep the water clear. Submerged oxygenating plants are invaluable to the natural balance of the pond. Try things like ranunculus aquatilis (water crowfoot), hottonia palustris (water violet), potamogeton crispus (curly pondweed), and myriophyllum verticillatum (milfoil). They will also help support the algae-eating animals, such as water snails and tadpoles.

Most oxygenating plants grow well, but depending on your local conditions, you may have to try several to establish which grow best. Most are easy to control so they shouldn’t get out of hand. However, do bear in mind that some oxygenating plants are invasive. Things like parrots feather, have the potential to escape and overwhelm native plants.

A fountain or a waterfall makes a lovely water feature. They look good and serve a practical purpose – adding more oxygen to the water. Installing a waterfall or fountain will require a pump which can be combined with a filter and a UV clarifier. These also help to keep the water clearer.

If planting water lilies, remember that they don’t like being splashed, so arrange fountains accordingly.

Other tips to reduce algae in a pond

This pond has a concealed pump and filter system.
Image source: Del Boy

It’s part of the natural pond cycle that early in the season there will be an algae bloom, when the water first warms up. Then the oxygenating plants start to work, the vegetation grows and the lily pads will spread over the pond surface. Within a week or two the green bloom fades and the water becomes clear. The period of green should be limited to a couple of weeks early in the season. If it continues beyond a few weeks, here are some other things to bear in mind.

The size of a pond can affect its natural balance. A larger pond will maintain its natural balance more easily while small, shallow, under-planted ponds will heat up faster and suffer more from algae.

I have found barley straw effective, although it doesn’t seem to work for everyone. The straw decomposes in the water inhibiting the growth of algae.

A pond filter can be very helpful to remove algae. If you have a significant number of fish, a filter is essential to maintain good quality water and to ensure that fish excreta doesn’t feed the algae. It is important to buy the right size of filter for the volume of water (determined by the size and depth of the pond), and number of fish to be stocked in the pond. Specialist suppliers offer advice on this.

There are chemicals which can be added to the water, but I’m not happy to add them to a pond which is full of wildlife. It is a matter of personal choice. The sustainable way forward is to build up the ecological balance in the pond so that it naturally takes away the algae.

With a little effort, it is possible to have an algae free pond. Apart from the early spring bloom, algae is not inevitable as long as you have a few tricks up your sleeve to keep it at bay.

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