The Magic of Green Roofs

It has been three years since we planted the green roof for our new house with wildflower plug plants, which has turned out to be a fabulous success. For many, “green roof” is synonymous with “sedum roof”, p1080079we started off by colour bombing it with annuals while the slower growing perennials developed.
This sense of progression and change – like a wildflower meadow – is part of its fascination. Fortunately I can see it from my office window on the first floor! Its colours change through the season and species come and go depending on the weather. It’s much past its best now, but still lovely.

Green Roof in 2014
Green Roof in 2014
Also like a wildflower meadow, the roof serves as a wonderful habitat for all sorts of invertebrates and birds as well. Our wagtails love it, and we see different finches on it regularly too. Fingers crossed we might even have something nest on it next year!
p1080073Conditions on the roof are almost opposite to the wet clay hereabouts, so we can create diversity as well as a very different look with it. Wild Thyme and Scabious (pictured) do very well on it, for example, which we would never see normally here. There are some areas where the growing substrate is evidently more fertile than in others and the moisture retention in the substrate also varies, which gives diversity to the flora and flora within the roof too. Some areas still have a lot of bare earth, whereas others have almost tussocky grass.
p1080085It can be pretty hostile for the plants on the roof, which means I don’t need to do much more than weed it a couple of times a year. Things don’t grow to great size, and annual weeds generally don’t survive at all. In the first year I watered it a couple of times but now I don’t bother. I’ve just sown some Yellow Rattle this year to keep the grasses down a bit in some sections, too. What’s not to like?

Yellow Rattle

Yellow Rattle, Rhinanthus minor
Yellow Rattle, Rhinanthus minor
I’m often asked about Yellow Rattle, Rhinanthus minor. It’s an attractive annual wildflower, good for bees, and which used to be common. Farmers don’t want Rattle in their meadows, however, as it parasitises grass and reduces its vigour. This makes it invaluable in establishing wildflowers in an existing sward, particularly where the grasses are vigorous and aggressive. I’ve written about it before extolling its virtues and explaining establishment.
I wanted to share some photos today,
Grass without Rattle
Grass without Rattle
however. It’s difficult to explain what grass with Rattle in it looks like; it doesn’t look sick but is much reduced in vigour. I thought a couple of pictures from one of of our meadow areas would illustrate that. This is an area
Grass with Yellow Rattle
Grass with Yellow Rattle
with relatively fertile soil and well established vigorous grasses. The grass without Rattle has already formed a thick sward up to two feet tall.
The area next to it which I seeded with Rhinanthus last autumn looks quite different. It had the same grasses and the same soil. The grass doesn’t look diseased or unhealthy – it’s just much reduced in volume and in size, to a height of about 6 inches in this case.

When is a Wildflower not a Wildflower?

I am happy to report that this year Swansea is going to be more colourful than ever, due to the council sowing over 40,000 square metres of flowers this spring. Well done Swansea Council.

Swansea roundaboutLet’s just get this straight, though. Most of the “wildflowers” they are sowing might be wildflowers, but they’re wild in places much more exotic than the principality. Like South America or California. I’m not going to get into any debate in this blog about the relative merits of this kind of planting as against using our own wildflowers – what I want to say is much more simple.

In the UK people understand “wildflowers” to be British wildflowers. Simple. Not Californian poppies or Gaillardia, but species naturally occurring here (no, I’m not going to get into the argument about how long a plant has to be here before it is “native”). I reckon they can also reasonably expect any “wildflower” seed they buy to be harvested here from plants grown here.

That’s it.

Our Specialist Seed Mixes for Solar Farms

We have supplied specialist seed mixes to over seventy solar farms or parks in the UK, most of which we have seeded too.

These are usually mixes of British native wild flowers and grasses in combination. Seed mixes like this significantly enhance biodiversity on what was typically agricultural land, and are also relatively easy and cheap to manage. This is particularly true if the sites are grazed through the winter.

They’re also – in our experience – surprisingly easy to establish. The sites we’re working on are usually low grade land, so competition from aggressive weeds is less than you might think. In any case, starved of chemical enhancement, “fertile” soils often become infertile very quickly!

The caveat to these comments on ease of management and establishment is that is that weed management has to be done promptly and pro-actively. We sometimes find that neither budget nor management system allows for this.

Solar site in Hampshire, poor calcareous soil, 6 months after seeding (freakishly good!)
Solar site in Hampshire, 6 months after seeding, poor calcareous soil. Freakishly good result, using local direct harvest mix.

There is absolutely no “one size fits all” approach, as you might think if you read the blurb on some suppliers’ websites. There’s a whole range of options, to fit budget and site specifics. We work with ecologists and developers to come up with an ecologically appropriate solution specific to an individual site, which won’t break the bank.

There are some guidelines which we follow, however.

1. Always, always use seed with documented UK provenance.

2. Always, always use wild species, not agricultural cultivars. Cultivars of wild flowers, like Bird’s foot trefoil, don’t last very long and don’t benefit wildlife to the same degree that the wild plants do. “Wild flower” and grass cultivars grow much faster and much bigger; they will need a lot more cutting. Buying seed mixes consisting of agricultural cultivars is a false economy.

3. If possible, use a direct harvest seed mix with local provenance. This will be more appropriate, produce better results, and – frankly – look good in terms of corporate PR. These mixes are also typically great value for money, given their high floristic content.

4. Don’t be tempted to seed at less than 30kg/Ha – 40kg is ideal. There are some folk who recommend seeding down to 20kg. This won’t give you a reliable result.

5. Always find an experienced seeding contractor (like one of ours!). Sowing wild flower seed is a very different thing to drilling wheat.

6. Try to use a minimum of 80:20 grasses to wild flowers, if your budget allows. Sometimes specifications are 90:10 or even less, which mixes are cheaper but much less effective.

7. Don’t be tempted to use commercial “bird seed” mixes. These look cheap, but have limited value to invertebrates and require regular reseeding. A traditional wild flower meadow mix will not.

8. Look at the design of the site. The width of the arrays themselves as well as the alleys between them can dictate the type of seed mix which will work best.

9. Manage expectations. Wild flower meadows aren’t built in a day. The longer they take to establish the more diverse they can end up.

10. Try to ensure the site operator follows an appropriate management regime.

Seed mixes for solar sites
Site in Oxfordshire, 18 months after seeding. Difficult, heavy soil.

Road Verges and Wildflowers

Floristic verge
Our verge, 2014
There has been a sad little story in the Press over the last couple of days about the hamlet of Owermoigne. Apparently Dorset Council have failed to mow the grass – and weeds – for eight months, although they promised to mow it seven times a year. The BBC website shows pictures of waist high grass and dock. This has meant the village has had to withdraw from a “best kept village competition”, although since the story broke the council has cut it again.

Why is this a sad little story? Firstly, if the council hadn’t mowed the bejeesus out of the village verges over the years this problem would not exist. There would be a riot of wildflowers instead of the only weeds and grasses aggressive enough to have survived this regime. Taking a “hay cut” after mid July and just keeping them tidy throughout the autumn and winter would have saved the taxpayer a small fortune too. Plantlife have been promoting proper verge management to encourage wildflowers and – who knows – it might catch on.

Secondly, if the verges of Owermoigne had been managed in a low cost wildflower friendly way over the years, you know what? I bet there’s no way the village would have won awards in the best kept village competition in 2004, 2005 and 2011. That’s the really depressing thing; it seems like we want all of our public spaces to look like the playing fields we no longer have.

A meadow in winter

We have some meadow areas in our field here. They’re now just starting their third year, and coming on nicely. We’re using them to show off some of the different seed mixes we sell, so they’d better do well!

Meadows in winterOne thing many people don’t do is to keep their meadows cut short over the winter. If you want a tussocky look with a lot of grasses – great for voles, thence raptors – that’s one thing, but for a “traditional” hay meadow look you need to cut it short. And keep it short until the spring. Your medieval farmer would have taken the hay cut then have livestock in the field for most if not all of the winter. Hooves pushed seed into the mud and the grass was nibbled low. I use a sit on mechanical sheep to achieve the same effect.

Keeping your meadow like this in winter not only makes it tidy, but also allows sunlight to reach the perennial wildflowers. These typically form low lying rosettes which aren’t harmed by cutting, even very tightly. Most over-wintering insects, eggs and larvae are unharmed too, particularly as we do leave areas around the margins which we will only cut every 3 years in rotation. Mowing also gives wildflower seeds a chance to germinate and flourish. I’m thinking particularly of Yellow Rattle, which is an early germinating annual. It’s also true that removing the cuttings will reduce fertility.

If we didn’t cut our meadow areas like this the grasses would take over and we would lose the diversity and colour wildflowers bring.

A Sense of Perspective

WildflowersI’ve just got back from an indecently long hols in France, which, yes, was lovely thank you. We did a round trip, with three days of World War One battlefields before heading down south for some sun (and fab wildflowers!), then up through Brittany after dropping our youngest off for his French exchange.

Joseph Charles Smith
Great Uncle Joe
The first leg was pretty sobering. I’d done some homework on relatives in the war before leaving; all the men of that generation in the family fought on the Western Front. I had grandfathers who somehow survived and great uncles who were killed. I won’t bore you with the details, but their individual stories are both unexceptional and moving. In particular, the odds of my father’s father surviving* were very long indeed. It’s a miracle I’m here.

The stories of these men put current worries into perspective. Is this something we have trouble doing, in everyday life as well as in politics? In a complicated and news saturated world we increasingly just respond to simplified cues suggested by the media.

It happens on the environmental front too. Dave Goulson, in his new book “A Buzz in the Meadow”, asks why we are apparently so unconcerned about collapsing insect numbers while at the same time as getting in a state about the cuddly panda, an animal with no known ecological value other than just existing.

In a similar vein, I was talking to the MD of a renewable energy firm about the abuse he has had at planning meetings. He has even had death threats, bizarrely. He runs a genuinely ethical business and is committed to community engagement, reducing fossil fuel emissions, etc etc. He was at a dinner where he sat next to a director of BAT, the cigarette makers. Out of curiosity he asked him how many threats he had had over the years. None. How weird is that? Our local town has a FB page and the size of the threads on potential nearby renewable projects dwarfs anything else on it. Apparently folk are as hostile to renewables as they are to fracking – when they’re proposed on local sites. They’re a lot more wound up about it than any other issue out there.

Come on people, let’s think about what history and science can teach us and get our sense of perspective back.

*Cpl. A.B. Mann, Machine Gun Corps (36% casualty rate), served with 51st Highland Division (25%), 1916-1918. Fought at the Somme (High Wood and Beaumont Hamel), Passchendaele (Pilckem Ridge), Arras (Roeux), Cambrai (Flesquieres), Bapaume, etc. As a completely irrelevant aside, somehow the thought of this 18 year old from Streatham fighting in the desperate circumstances of industrialized war to the skirl of the pipes makes me very opposed to Scottish independence… And talking of the pipes:

A Secret World

A secret worldThe green roof was one of the best decisions we made when building our new house. I’m a total convert. The practical advantages of having one are well known – great insulation, controls rain water run-off and long life. I have been delighted by the aesthetic delights of it, however.

We went with a wildflower green roof rather than using altogether duller sedum. It’s now a secret world, pretty much. It’s over our ground floor so we can see it from our office on the first floor, although the only way I can watch its minutiae is through my camera or binoculars from here. I can’t get up onto it except by ladder, and only do as a real treat. Most of what we’ve planted has taken, and this mini-jungle is creating its own mini-ecosystem. Solitary bees whizz about and have started nesting in the timber sitting up there which I drilled holes in. Butterflies flutter curiously, while on the ground level I can see beetles and spiders scuttling around. Tiny delights appear through my lens. a secret worldA plantain in flower or a goldfinch foraging for seed, a poppy bending under the weight of a ladybird or the purple pollen a bumblebee collects from a self seeded phacelia plant. Common plants look weirdly exotic and exciting, like the alien forest of Salad Burnet flowers above.

And unlike creating a traditional meadow on the ground it has been incredibly easy and instant. The substrate is miserly enough that any dock, nettle and thistle brought in by birds all struggle until weeded out. We didn’t plant any grass, but the plants which have arrived behave very nicely.

Who needs a garden?

What is a Wildflower Meadow?

What is a Wildflower Meadow?

Dear Habitat Aid,

What is a wildflower meadow? Every time I open a magazine and read a feature about wildflower meadows they seem to look very different. Although they look lovely, I don’t recognize many of the wildflowers I see in the pictures either. I want to have a wildflower meadow area in my garden and although I’ve read your other blog about it I’m still confused. Help!

Confused from Chiddingfold
Dear Confused from Chiddingfold
Wildflower meadow, SomersetIt is confusing. It seems to me that in the UK people understand very different things by “wildflower meadow”. At one end of the spectrum ecologists and conservationists call it semi-natural grassland. This is grassland untreated by herbicide and “unimproved” by fertilizers, but which has been altered by human activity like grazing livestock or cutting for hay. It is what you might think of as “traditional wildflower meadow”. There are 5 different types in the UK; limestone grasslands, marshy grasslands, acid grasslands, lowland meadows and pastures, and upland hay meadows. Wildflower meadow, SomersetTheir flora consists of native British grasses and wildflowers, of which they typically have between 15 and 40 species per square metre. These wildflower meadows all look quite different as their plants vary according to their locality. This variation can be very local. These three photos were taken within a month of each other, and Wildflower meadow, Somerset show different areas of the same traditional wildflower meadow around the corner from us in Somerset. It’s grazed by cows, by the way.

We’ve lost 97% of these wildflower meadows as land use has changed. Recently there has been a lot of interest in putting wildflowers back into the landscape, but in a more mannered way. Rather than trying to mimic traditional meadows, some designers are promoting meadows without grass, using native and non-native wildflowers. Nigel Dunnett calls these “pictorial meadows” and they’re very voguish. There were a lot around at the Olympic site, for example. They’re good for bees because they provide season long nectar flow, but they were orginally about visual impact.

What is a wildflower meadow? Cornfield annuals
Cornfield Annuals
People are also unclear about the difference between annuals and perennials. When some folk think of wildflower meadows they think of flowers like poppies and cornflowers – annuals. This is a slightly different thing again as they need a different regime and don’t really constitute a “meadow”. They also have limited biodiversity value themselves, but they’re often good to combine with perennials.

I hope that’s helpful.

Nick Mann
Dear Nick,

Now I’m really confused. What kind of wildflower meadow area do I want in my garden? I want something which will look nice, is easy to manage, and brings bees and butterflies into my garden. Are “pictorial meadows” actually bettter for doing this? Help!

Hi Confused,

Don’t despair! There’s no rule about this – I want you to end up with a wildflower meadow which makes you happy.

Whichever version you go for it’s a myth that they’re difficult to establish or manage. So long as your seeds or plants are sourced from a good supplier and you follow some basic guidelines you’ll find it easy. Remember whichever type of wildflower meadow you go for will require some simple management, although much less than a lawn or border.

What are your priorities? Go for a “traditional” wildflower meadow if any of these apply:

Six Spot Burnet
Moths Like Meadows Too

1. You’re restoring or creating a meadow area in a field or paddock.

2. You want to help preserve local British wildflower populations.

3. You like the unstructured look of it.

4. Improving biodiversity generally is an important aim for you. Designer combinations of non-native and native wildflowers can provide longer nectar and pollen flow for pollinators, but a traditional wildflower meadow will give you more biodiversity generally. Native grasses, for example, provide foodplants for butterfly and moth larvae.*

I should declare my interest; these tend to be the sort of people who are our clients. It’s particularly important if you’re going down this route to source your seeds or plants carefully, by the way. You wouldn’t want to use Slovakian seed to restore a meadow in Slough.

If your aims are different, by all means look at the Pictorial Meadow solution. These can give you a more designer, impressionist look, and have a longer flowering period.

Don’t feel that wildflowers should be restricted to wildflower meadows, by the way. You can use them in formal planting schemes or rubbing shoulders with ornamentals. Contrary to popular belief many of our native wildflowers have long flowering periods and behave beautifully in a garden setting.

Good luck with your wildflower meadow, and if you’ve got any more questions just drop me an email.


*I like the look of our grasses too, and they can be helpful in improving soil structure.


I toddled off to Poundbury today on the coat tails of some local ecopreneurs, and had a fascinating time. Poundbury is Prince Charles’s homage to Hardy outside Dorchester, which I’ve often passed ferrying children to play various rugby matches. As someone building a contemporary house in their back garden you would expect me to hate it and, it’s true, I just don’t get the architecture at all, which reminds me of Trumpton (talking of which, the neoclassical fire station is particularly odd; I’m not sure even Pugh, Pugh, and Barney McGrew* would be comfortable with it). It’s had enough of a pasting on that front over the years not to dwell on it. Having lived in Zurich for a bit I’m also suspicious of the Swiss approach to community living, which this seems to be like.

Photo: J.V.Energen
Anyway, what was interesting about the visit wasn’t my (rather predictable) reservations, but the anaerobic digester, which was the main reason I was there. Needless to say, the Germans have been generating gas from decomposing waste for years, and as needless to say we’re only just starting. The new digester at Poundbury is going to be just fabulous – really inspirational – and I can’t applaud the initiative highly enough. They’re going to be making enough gas for the WHOLE of West Dorset. The site is beautifully landscaped and – oh yes – it’s not smelly either. The end byproduct, “digestate”, can be used to fertilize fields and gardens. Interestingly for me, wildflowers might be a really good high calorific input for the plant, which would be brilliant; I’m always looking for economic reasons as well as the obvious ones for restoring what ecologists call “floriferous grassland”.
I’m really impressed when I see initiatives like the Poundbury “AD” actually coming to fruition. Actually happening. The people driving it don’t just have to be just hugely enthusiastic but also very bright. They have to be endlessy patient, good communicators, backed by an organization with deep pockets and a long term view. Most of all they have to be achievers. Whichever world I’ve been involved in over the years, from uber-capitalist to local conservation charity, this is a rare cocktail indeed.
Oh, and I should also say that, buoyed by my excitement, I popped into Dorset Wines on my way out of town. Poundbury works for them, and on the evidence of their enthusiasm and their Petit Chablis, Dorset Wines rather works for me. Next time we’re playing Dorchester RFC (away) I will return…

*This Trumpton reference attests to my advanced age.