When is a wildflower not a wildflower…

On July 2nd, BBC News published an article with this headline: Why are England’s roadsides blooming?. The article goes on to explain that “the UK has lost 97% of its wildflower meadows in less than a century”, and that “roadside verges are particularly hard hit”. Both statements stem from a campaign by the charity Plantlife, started in 2013 to raise awareness on these often overlooked habitats. One of the aims of the campaign has been to encourage private landowners and councils to change their management practices (“cut less, cut later”) in order to allow wildflowers to re-establish.

Yet the first photo used to illustrate the article is a multicoloured sea of plants that are growing in the wrong place. I can spot non-natives, such as golden tickseed (Coreopsis tinctoria) and California poppy (Eschscholzia californica), both annuals from North America; and Ammi majus, an umbellifer from Egypt. I can also see native poppy (Papaver rhoeas) and native larkspur Delphinium ajacis, both arable weeds that grow naturally on disturbed ground and agricultural fields, not in grassy roadside verges.

On a closer look, one notices that half of the pictures that illustrate the article have been provided by a commercial company called Pictorial Meadows, which sells a variety of seed mixes (annual, perennial, mixes for roof gardens, Mediterranean meadow etc). Pictorial MeadowsTM (a trademarked concept) was founded by Nigel Dunnett, a Professor of Planting Design and Urban Horticulture at Sheffield University. Although the company prides itself in its knowledge of “meadow ecology”, the aim is to offer “naturalistic but idealized meadow like landscapes that establish relatively rapidly, actually perform and thrive in normal conditions and provide delight for a very long period.”

This sounds wonderful, doesn’t it? As a horticultural feature, sown mixes are certainly a success. Offering an array of colours and textures, long lasting, requiring little maintenance…

So, what’s the problem with sown wildflower meadows?

  1. They often contain non-native plants

Many “wildflower” mixes contain seeds of non-native plant species. Is this really an issue? After all, 70% of plants grown in UK gardens originate from abroad.

There’s no need to be pedantic about “natives”. Many species (around 150) in the British flora that would be considered as native are actually “archaeophytes” (ancient introductions), that were imported before 1500 AD.

archaeophytes
Poppies? Cornflowers? Annual mercury? Red deadnettle? All ancient introductions to the UK.

Of course, we know that some plants imported into the UK for ornamental purposes, such as Japanese knotweed and Himalayan balsam, are now terrible pests. But among the non-natives imported to Britain, only a very small proportion become a long-term problem. Williamson’s (1992, 1993) suggests that out of the 10% of non‐natives imported into a region and that escape into the wild, only 10% of these establish, and out of the 10% of established species, 10% become invasive.

The risk of North American or African species escaping seed mixes and becoming a problem in the wild is (probably) not a strong enough argument. This does not mean it is a vain one. Unfortunately, the impact of naturalised plants on ecosystems can sometimes only be seen and understood after decades, when it becomes harder to fight the invasion.

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Verbena bonariensis, a favourite of perennial “meadows”…and a future invasive?
  1. Seeds of “native” plants are sometimes sourced from abroad

Certain wildflower mixes appear to be more virtuous, offering a selection of UK native species. Yet the seeds can be sourced from abroad, often from Southern Europe, and this is not always mentioned on the label.

Some may argue that in these times of climate change, bringing in genetic material from plants growing abroad in different conditions (drier soil, hotter summers, other pests & diseases) could help improve the adaptability of native species. As this article explains, this is partly true. With climate change, exceptions to ‘local is best’ may increase.

However, bringing in non-local seeds poses several risks:

  • it can “pollute” the genetic diversity of the local population. If crosses happen between plants of foreign provenance and local plants of the same species, this can, over a period of time, lead to the reduction or even the loss of locally adapted genes. This can cause non visible changes (eg a decrease in resistance to a local pest) or visible changes (eg a slight modification of the flower colour can make the plant less attractive to pollinators).
  • it can affect the interactions at ecosystem level. For example, the amount of cyanogenic compounds (chemicals produced by plants to avoid being eaten) contained in leaves of white clover increases with the latitude. Plants from Southern Europe grown in the UK might therefore suffer more from herbivory than local plants. Non-native genotypes can also have a slightly different flowering time, which can affect the local insect population.
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A seed packet of “Wild Flowers”, all UK native or archaeophytes. But were the seeds collected in the UK?
  1. They are often short lived.

While perennial meadows offer a mid to long term option, many “wildflower” seed mixes are annuals. Although there will be a degree of self-sowing in year 2, one will often notice that a few species have become dominant. The colour scheme, which is often a strong selling point of the “wildflower” mixes is then lost. As a result, most annual meadows have to be sown again every year. This requires soil preparation and rotovating, which have less than ideal carbon costs. In addition to the human effort needed and the cost of purchasing seeds again and again, can this be considered as sustainable?

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A perennial non-native meadow at the Barbican centre, London
  1. Actual “wild” flowers are destroyed in order to sow wildflower mixes

Many people do not realise that in order to sow wildflower mixes, the ground has to be “prepared” ie laid bare. Although mechanical work is an option, councils and landowners often use glyphosate (Roundup) to clear any existing vegetation.

A good example with this golf club, posting photos of “prep work” in April for seed sowing:

I am not proposing a debate on glyphosate as it isn’t the point here, but isn’t it just sad that we have to kill plants in order to sow others? Of course, this is normal practice in agriculture before sowing crops. But “wildflower” mixes are usually sown in parks and gardens. A lawn left to grow will get covered in flowers on its own, as shown in the tweet below. No seed packets to buy, no soil preparation needed.

  1. They might not support as many invertebrates

Seed providers usually advertise their packets as being great for bees and other pollinators, but is this true?
A study published by researchers from the RHS and Sheffield University gives the following concusions:

  • more flowers is better, whatever they are
  • native and near-native plants (such as close relatives of UK species from North America) appear to be better for pollinators than exotic plants
  • there are differences depending on the group considered. For example, hoverflies prefer native plants, honeybees near-native plants.
  • Exotic plants can extend the season & provide additional resources.

On a first glance, these conclusions would tend to be in favour of sown flower mixes, which often contain a variety of natives and non-natives.

This other study focused more particularly on sown mixes, examining the pollen and nectar yields of annual and perennial plantings. Here’s what they say:

In both annual and perennial treatments, up to 100% of nectar and pollen resources early in the year were provided by native perennial weeds, particularly Taraxacum agg., Ranunculus repens and Trifolium repens. While potentially problematic for green space managers from the point of view of public acceptance of planted meadows, and notwithstanding the pollen quality issues for some species discussed above, these weeds are favoured floral sources for bees and butterflies through spring and early summer in urban environments [51,117120] and more widely (e.g. [121124]). As managed, the mixes we used have very limited potential for provision of resources early in the year. While earlier sowing of an annual mix can result in earlier flowering when weather conditions allow earlier germination, this comes with higher risks to green space managers of meadow failure through rotting or predation of seeds or frost damage to young seedlings.

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Mean nectar sugar mass per 24h per floral unit for species in A. the annual seed mix, B. the perennial seed mix, and B. native weeds in either mix.

The authors go on to say that spring-flowering perennial plants should be added to mixes (such as wood anemone, white dead-nettle or lungwort), and that temperate woody species such as hazel,  hawthorn or cotoneaster should be considered in park settings as they can provide early season resources to insects. They also insist on the role of grasses, which contribute to the pollen provision for pollinators.

The conclusion of these studies is that although the presence of non-native species in mixes can be beneficial in late season (flower mixes are often cut late compared to native meadows), the use of these mixes comes with a fundamental problem: they flower too late to be useful to insects in early season, when resources are scarce.

  1. They give people a wrong idea of what nature should look like.

Take this example in East London. Opposite a new development along the Thames, a strip of land has been sown with a wildflower mix. There’s no denying that it looks very pretty, and that it brightens the view on a dull day. But these are all cornfield annuals such as corncockles and cornflowers, which, as the name says, would naturally grow on the edge of fields, in the countryside.

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Cornfield annuals along the Thames in London…wrong plants at the wrong place

About 100 meters further down the Thames Path, this is what natural vegetation (not all native!) looks like. Brambles, red valerian, sea aster, hedge mustard, wall barley, common mallow, sea plantain…

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Now, people were gushing about how pretty the sown flowers looked, and posting pictures on Instagram. Nobody was casting a glance on the wild flower patch, even though it was almost as colourful.

And this, more than the ecological downsides, is what makes me so sad about the popularity of wildflower mixes.

One study has shown that people find the most colourful meadows more attractive, and that they imagine them to be the most species-rich. Yet natural landscapes which incorporate a significant proportion of green (27% of flower coverage) are thought to be the most restorative, the ones that produce the most health benefits.

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A restorative landscape?

To me, these sown annual meadows are the Victorian flower bedding of the 21st century. Sown annually, providing interest in summer and vivid colours, they are not sustainable, require intensive labour and don’t provide the same ecosystem services as native vegetation.

We have become so disconnected from nature that we cannot see the beauty, the normality in letting our parks, our lawns and roadsides fill with flowers and sweeping grasses. We say we love nature, but we only seem to like it when it is managed.

This lady for example, was reported to the Council by her neighbour, for not cutting her grass (which is home to orchids and a large variety of wildflowers).

Liz Humphreys tweet

The BBC article, and several others posted since, have created a debate on Twitter, between partisans of wildflower meadows, and people who think they are atrocious human creations. This has led to heated exchanges of arguments.

Personally, I don’t like violence, I don’t think it is constructive. But I feel that the popularity of these sown meadows has grown thanks to good marketing, rather than scientific evidence. And as a scientist, this bothers me.

Even then, surely, the benefits of sown wildflower mixes outweigh the inconvenients? They require less mowing, they are good for insects, they bring green into cities and make people feel happy.

I don’t dispute that. However, I find it such a shame that, in one of the most “nature depleted” countries in Europe, companies have seized the opportunity to reinvent an image of nature that fitted their commercial objectives. Instead of placing us within the ecosystem (whether it is an urban or rural one), we are once again conquering it. By using cornfield annuals along the Thames, WE decide what WE THINK nature looks like.

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How different?

I am not saying that all mixes should be banned! I DO think they are useful in certain circumstances, where no native vegetation is present, in temporary landscapes where quick effect is needed, in raised beds etc.

Here are my suggestions to anyone who’s thinking about planting one:

  1. If possible, let natural vegetation regenerate. It may take a few years to attain a result which you feel can be aesthetically pleasing.
  2. If not possible, use a mix of perennial and annual native species, of UK provenance
  3. If the use of a seed mix is necessary, try to choose one appropriate to the local setting
  4. If people complain about the lack of flowers, the fact that it looks neglected, teach them what wildflowers really look like!

9 Comments

  1. Yes, as a local government conservation officer I always push back against the use of these seed mixes. Let’s see what is in the sward already and how we can enhance that. This well written blog will inform my future conversations about this issue.

  2. Thank you for your impressively researched, clear, thoughtful, and heartfelt post. My Twitter feed is buzzing with opinions around the issues you raise.
    As an amateur botanist and entomologist, I agree with you completely. But I’m also a hands-on volunteer at an urban nature reserve in York (https://stnicks.org.uk/) that used to be a landfill site. St Nicks is also helping local communities to biodiversify their species-poor meadows. Sometimes it helps just to turf-strip and sow some archaeophyte cornfield annuals, just for impact. Even though we know grassland ecology is complicated. (How to make a proper NVC MG5 from scratch, anyone?)
    So… compromises must be made. Many people do seem to have recently realized how beautiful and ecologically important grasslands can be. Fantastic! Maybe we should ease off a little about what they sow, and what a “wildflower meadow” should look like. Get them sowing, even rubbish commercial seed-mixes from “The Man”. And then gently, but authoratively, explain things.
    Sean

  3. Reblogged this on Walks, rides and what's there and commented:
    As very much an amateur botanist, who loves rather than knows flowers I have been wary of this wildflower mixes.

    This is cloear on the Broughton bypass in Lancashire.

    To me it is more important to encourage present verges with restricted mowing

  4. This is what I have been saying for years. There is something completely different about wildflowers growing naturally and far more pleasing. An excellent article.

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