The Expert Guide To Biodiverse Gardens
A Wildlife Friendly, Biophilic Garden?
Biodiversity, simply as a high level concept, may be defined in three ways. The overall diversity within each species (and for our purpose that translates to encouraging individuals of a species to take up home within your garden), the diversity of different species (namely having a variety of species sharing your garden alongside you and your family), and the diversity of eco-systems (having different habitats within your garden to encourage a wider range of species).
Before looking at the finer details of the wildlife garden, I would just like to mention why nature and biodiversity should be encouraged in your garden. The truth is that in a world of climate change, pesticide overuse, and habitat loss what we do in our gardens truly matters to the world around us, and not just for the creatures and plants with which we cohabit in our gardens. Wildlife in our gardens sets a precedent that will continue to seep into the national consciousness - becoming part of national policy - providing space for wildlife across the wider landscape. Biodiverse garden design in Yorkshire, and across the rest of the UK, is therefore vitally important.
Returning to the matter at hand, the good news is that encouraging biodiverse gardens is simple. You just need a garden and a variety of plants to make a start…and then you can make improvements from there.
In a 30 year study of her sub-urban garden in Leicestershire, renowned ecologist Jennifer Owen identified at least 2,673 different species either living in her garden or just passing through (as beetles are so diverse there were 442 beetle species definitely identified). The most interesting point here though is that she didn’t specifically garden to attract wildlife - her garden was just relatively densely planted and consisted of paved spaces, a lawn, planting beds and borders, trees and shrubs, a vegetable patch, and a small pond. What was special about it? Nothing in particular - she simply recorded all the wildlife that she could record - moths, flies, worms, birds, mammals and anything else that crawled, walked, flew, or wriggled through her garden. Therefore gardens are a repository for biodiversity and all we really need to do is to make sure that the beds are full of a range of different plants.
The secret is therefore to design and plant our biodiverse gardens both for people and for nature. Key to this is selecting the right plants for your garden (based on its orientation, its soil, and its location) whether we attempt to develop a naturalistic planting style or not. This should then keep maintenance to a minimum, ensure the survival of the plants you select, and ultimately ensure your garden is somewhere in which you want to spend time. I will touch on this in more detail a little later on.
For now it is fair to say that just owning a garden and avoiding paving over it all in the false belief this makes it ‘easier’, or avoiding laying artificial turf, or avoiding using chemical poisons, will ensure that you are helping to support the natural world around you.
Wildlife friendly gardens - encouraging nature in
If time is short then there are a few ‘quick wins’ that can maximise your garden’s attractiveness to the biodiversity around.
The first is simple. Stop using pesticides, herbicides, or fungicides. Applying poisons to solve perceived problems just doesn’t stack up. Poisons don’t differentiate the wildlife you like from those species you would rather did not live in your garden and so it is essential to avoid their use wherever possible to promote biodiverse gardens. If you are growing something that requires poisons for it to survive when grown among the local wildlife then you are growing the wrong plant. Even previously acknowledged relatively benign glyphosate-based weedkillers have been shown to affect the gut bacteria of bees rendering them more susceptible to disease.
Plant selection is therefore vitally important when creating a naturalistically planted wildlife garden - and your options here are to employ a professional garden designer, to gain the plant knowledge yourself, or simply to look at what grows well in your neighbour’s gardens and select the plants that you like to form a palette of plants for your own garden (as you can be confident they will grow and thrive in your soil too)…
Of course with plants come weeds - not least because the act of planting new plants disturbs the top layers of soil and brings to the surface the seeds that may have been buried for years, allowing them to germinate. You just need to hoe these out - and this is often much easier than applying weedkiller anyway. Indeed many ‘weeds’ may swamp your plants but this is more often true in newly planted gardens, or where a garden adopts a Victorian ‘gardenesque’ style of planting (where plants are shown off as specimens with soil visible between each example). Bear in mind though that a weed is simply a plant growing where you don’t (think you) want it to grow and in many cases a garden can be improved by allowing some naturalism to be adopted in the development of a planting scheme - by selectively allowing some ‘weeds’ / wild plants to grow. It is not a case of having to weed the whole garden for the naturalistically minded gardener but rather a job of carefully editing what is there and pulling out anything that is invasive or simply in the wrong place.
Personally I am happy to live with moss in the lawn and ivy at the boundaries, although many consider these to be weeds. If moss is growing it is almost always because the ground conditions support its growth - and so if a new lawn is installed it will just lead to a year or two of moss free turf before it reappears. Similarly ivy, particularly under and amongst trees, can cover the ground to prevent other weeds and remain green throughout the dark days of winter. It still needs taming to keep it in check, and prevent more vigorous varieties scrambling into trees, but is a favourite of UK wildlife.
Finally, the mention of lawns above leads to perhaps the easiest action anyone can take to create a textured series of layers in the garden. Leave an area of grass to grow long and create your own mini-meadow. This has recently been popularised as ‘No Mow May’. The UK is ideally positioned to grow grass well (which is why grass seedlings need to be removed from flowerbeds) and many of our native invertebrate species will find shelter in longer grass - from ladybirds which eat aphids, lacewings (whose larvae eat aphids as well), to active hunters like centipedes. For a quick and naturalistic result it is also possible to lay wildflower turf which can look fantastic later in the same year it is laid.
It is the little things that we do that can sometimes makes some of the largest differences for the biodiversity within our gardens, allowing people and nature to coexist harmoniously.
How should wildlife friendly gardens look?
Where a naturalistic style is adopted within a garden it is essential that this looks intentional - otherwise many will feel the urge to tidy it up at some point! In her article Messy Ecosystems, Orderly Frames Professor Joan Iverson Nassauer wrote about ‘Cues to Care’ - these are essentially visually treatments/cues within different areas of the garden to show that it is cared for, and the naturalistic plantings are intended and deliberate on the part of the gardener. These can range from having areas of long grass whilst keeping some areas closely mown (or sometimes just having mown pathways through longer grass areas), a selection of topiarised trees or shrubs being kept neatly clipped, or bold blocks or patterns to the planting layout, to creating different ‘rooms’ in the garden, or careful detailing of the hard landscaped areas. In essence you need to have visible signposts to show that naturalistic areas are framed by human control to ensure that the overall space does not look “messy”. These are ideas applied by designers in many gardens - a well know example being the Topiary Lawn at Great Dixter.
On a purely practical level though, there are two further actions that will instantly attract a greater variety of life to your biodiverse garden. These are to plant a tree and to install a pond.
Options with regards to tree planting need to be carefully thought through. The most important factor is to select a tree of suitable size (ultimate size that is) to fit your garden. It is then worth considering what will fit well in the space. The ideal tree for the people using the garden is one that looks good all year - with blossom in the spring, verdant green in the summer, fruits and russet leaf colour in the autumn, and a good form in the winter. Any tree will increase the biodiversity of your garden but you may also want to select a tree species that has been present in the UK for a few thousand years to maximise the number of invertebrates it will support. Your choices of tree, where space is limited, may include Sorbus aucuparia (the rowan), Malus cultivars (crabapples), or Crataegus laevigata ‘Paul’s Scarlet’ (a red blossomed hawthorn). The choice of any plant, and particularly of trees, may seem daunting but suppliers will provide advice on suitable trees, or a professional garden designer, such as Haddon Studio, can assist in making these decisions to add to your biodiverse garden.
As for water features these can vary in complexity from a waterbowl that you ensure never dries out (by topping it up regularly), to a fully planted natural pond. Whatever it looks like to you though, pondskaters and other beetles will find any body of water quickly (just like bees suddenly appear in a newly planted garden) and other creatures will then follow - from dragonflies zipping through your garden, to frogs and newts, if you’re lucky. The key points to remember with a naturalistic ground level pond though are to install it in a natural dip (where water would gather, as opposed to being on a rise, so that it looks natural), to make sure it is installed level (preventing too much liner from being visible), and to ensure that the ground below is either free draining or else has a land-drain installed (so water does not gather beneath the liner and create a bulging ‘hippo’ of liner visible at the water’s surface).
Careful planning and specific features are therefore invaluable in the creation of the naturalistic and biodiverse garden as this not only ensures that the biodiversity of your garden increases but also ensures that it remains a beautiful and relaxing place for the people who share the space to lose themselves in.
Wildlife friendly gardens - the wildlife itself
There has been a lot of interest in recent years around attracting pollinators into your garden - be they bees or hoverflies (or beetles - most people don’t try to actively attract beetles, although perhaps they should). This is obviously a good thing as pollinator numbers are declining. The bees that you are most likely to spot in your garden (the honey bee, up to 24 species of bumblebee, and 2 species of mining bees) are just a fraction of more than 250 bee species found in total across the UK. Many bees should therefore be present in, or occasionally visit, a biodiverse garden - alongside the hoverflies whose markings and behaviours mimic those of bees (and of which there are over 280 species in the UK). Their continued survival depends in no small measure on preserving their habitats and ensuring that we do not use pesticides within our gardens.
It is not just the pollinators though that we should be encouraging within a biodiverse garden. In particular, nature provides invertebrate predators to keep garden pests down to levels where they no longer munch through your favourite plants, and make pesticide use unnecessary. Ladybird larvae, parasitoid wasps, and the common wasp all prey on aphids and are a vital part of any garden eco-system. Centipedes can also play a crucial role - hunting pests at, and just below, ground level.
These invertebrates are then supported by a range of other predators from our garden birds, such as great tits and wrens munching caterpillars and aphids, to those that devour our garden molluscs (slugs and snails), such as hedgehogs and frogs. If your biodiverse garden is anything like mine then it will be full of slugs and snails. There are certain plants that simply won’t survive the deprivations of these creatures (which thrive in our damp UK climate). I have come to terms with that, they are an essential part of the ecosystem after all, and the plants in my garden are therefore those that are less palatable so that we can coexist and no chemicals (or even beer traps) are necessary. This makes gardening a great deal less stressful for both the professional gardener and the enthusiastic amateur.
Indeed, just because something eats your plants does not mean it doesn’t have a place your garden. Butterflies and moths appear from caterpillars, and caterpillars eat plants. Of course some eat nettles (and other plants we would not necessarily miss) but others will happily much through your herbaceous border. Some nibbling of our garden does therefore need to be allowed, and the benefits pays dividends in the future. Not just in the moths and butterflies which will emerge from their chrysalises but also when we discover a particularly fascinating caterpillar.
Finally here I would like to turn to the garden wildlife that lives out of sight for most of us. Worms are the backbones of the soil environment and are vital to the overall health of your garden. I am an advocate, wherever possible, of the notion of ‘no dig’ gardening - especially after you’ve had your garden professionally designed. This is where, instead of digging over the soil regularly, the gardener spreads a thick layer of mulch over the surface, suppressing the weeds that are there, and then waits for the worms to incorporate it around the roots of the plants. The worms efforts also produce tunnels that create space for roots to explore when seeking oxygen or water, physically helping your plants to thrive. This produces a healthy soil with good structure which in turn sustains plants - and even heavy clay soil will visibly improve over time. This is not to say no dig equates to no work, but by not turning the soil there will be fewer annual weed seeds brought to the surface, meaning less weeding is necessary.
Worms don’t just frequent your soil though. A healthy compost heap will be full of them. There are seemingly thousands of posts across the internet, and even a few books, that are dedicated to composting (and so I won’t repeat that information here). However for any gardener committed to increasing biodiversity in their garden, the compost heap will act to increase that biodiversity for a range of creatures, not simply worms, that are attracted to processing the waste or making the most of the warmth generated by the process (from beneficial bacteria to Common Lizards and Slow Worms…if you’re lucky).
Naturalistic planting in wildlife friendly gardens
The whole notion and understanding of what to plant where is a little complex - there are many books written about it, with new tomes every year, and I can only scratch the surface of what is possible in an article such as this. Rather than simply listing my favourite plants though I want instead to concentrate on what you should be thinking about when selecting plants, in terms of maximising biodiversity in the naturalistic garden.
The first stage of creating a planting scheme is to think about it in the same way that many designers plan their schemes - by thinking in terms of different planting layers and areas, and where they should go to create a biodiverse garden.
For example, where will the lawn be? Which areas will be planted and will they consist of mainly ground cover, herbaceous perennials, evergreen perennials, or shrubs? Obviously you can dot shrubs amongst the perennials (and vice versa) but at this stage you’re just trying to envisage how those layers will look to start with. This is a particularly useful exercise when making sure that the beds to be planted are not too small in area and will help you to create an effective tapestry of habitat types across your garden.
Trees create a particularly important focal point in your garden - not just for you but also as perches for birds checking that it is safe to come in and explore, for example. Unless you are good at visualising in 3D then the simplest way to decide where to plant your tree is to take a long cane and pop it in position and then check it from all angles, inside and out, before settling on its optimum location. This is the way that Lancelot ‘Capability’ Brown used to work on large country estates and works perfectly well today, whatever size your garden may be.
The next crucial step is to understand your soil and there are a few key points to understand before selecting plants. You need to know does your soil stay wet for most of the year, totally dry out in summer, or is it “moist but well drained” - a catch all description of plant moisture preference for plants that should do well in most gardens. This will help to select plants that should survive in your soil. Second you need to know if you have a clay soil, or a sandy soil, or a loamy soil. This is closely linked to soil moisture (clay soils stay wet longer, sandy soils drain quicker) and again is important when selecting the right plants. Thirdly you need to know if your soil is acid or alkaline. Working often in areas with a chalky - and therefore alkaline - soil I see time and again people who have planted rhododendrons or camellias (which are acid loving plants) that have subsequently turned yellow, dropped their leaves, and died. This is not what is often perceived as a lack of gardening ability but simply putting the wrong plant in the wrong place. By ensuring you understand the soil in your biodiverse garden then it is possible to select the right plants for your particular garden soil type.
Finally we come to the plants themselves. With an understanding of the soil it is then possible to check the plants we wish to select (using our own knowledge, or books, or Google, or simply checking plant labels at the garden centre) and therefore we make sure that the plants chosen are suited to our gardens. There are an amazing number of plants on the market for gardeners to buy and it is easy to get overwhelmed - the RHS Plant Finder for 2020 lists 81,000 species and varieties. When filling beds and borders though it is best not to plant a multitude of different species but instead to buy plants to plant in groups (I usually plant in groups of 3, 5 or 7) to ensure that you get an eye-catching display. You then repeat these groups across different ares of the garden - to tie the space together, making it feel both unified and showing that a clear design intent underpins the scheme that has been created. I also like to mix ornamental grasses in amongst the plants to give a wilder feel. Don’t forget to include native plants as well!
If you need help in creating your biodiverse garden then Haddon Studio can help you to design your garden, and select the right plants, to create a garden where people and wildlife can coexist…for more information on how we design for biodiversity please refer to our Biodiversity page.
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