How gardening writer Alys Fowler set out to explore her city and ended up finding herself

But work, modern life, gardening and marriage to a penniless American artist called Holiday who suffers from cystic fibrosis kept her rooted to her home in Birmingham. However in 2014, in an attempt to at least try to scratch the adventuring itch, she spent £1000 on a fire-engine red “pack raft” – imagine a blow-up kayak that fits into a rucksack – and set out to explore the miles of canals that criss-cross England's second city, a legacy of the industrial revolution but now an urban space which has largely been re-conquered by nature.

“I wanted to write a book about urban nature,” she explains. “I was looking for a method to move around Birmingham and look at the different kinds of nature there and the canal seemed like a good way to move physically, in an interesting manner."

The result is Hidden Nature: A Voyage Of Discovery, an account of Fowler's travels through a sunken, aquatic world of massive bramble bushes, slopes colonised by feral buddleja, morel mushrooms growing on the site of old graveyards, and a profusion of other plants with names only an avid gardener like her would know: hawkweed, celandine, wood anenome, Oregan grape, Crack willow.

What she found and was able to view from her vantage point on the water was an ever-changing tableau of the bizarre, the surreal and the surprising. On one trip, she became mesmerised by a large plastic horse floating just beneath the surface. On another she was propositioned by a man on the tow path. She glared at him until he went away, safe on her boat in the middle of the canal.

She saw couples arguing, men fishing, sullen youths smoking joints. She encountered life and death – an enormous, decomposing eel; a rat so infested with maggots its mouth appeared to be moving; a floating swan, its neck snapped at an angle – and was baffled by a flotilla of coconuts that passed her once. Later she learned that in Hindu tradition a coconut thrown into the water is a mourning tradition.

“The [dead] animals and the birds were big and smelly and bloated but the fish were fascinating,” she tells me with disconcerting relish. “You know they're there but it's not until you see them dead and floating that you realise how big they are. It's quite murky water so you can't see them close up. So seeing the fish dead was always really fascinating.”

She is, she admits, “given to poking at dead things. I do have a slightly ghoulish fascination about dead things, it's true. I find compost and things rotting really, really fascinating”.

One day, under a bridge and entirely hidden from view, she met a homeless man who had constructed a house complete with firepit, outdoor seating area and a bedroom decorated with women's handbags. She would see him regularly. Then he simply vanished.

But Fowler's title is apt in other ways and her voyage of discovery came to represent more than just an exploration of her physical surroundings. Her inner emotional life came under scrutiny too because as she paddled around the canals of Birmingham, Fowler began to realise something else: she was falling in love with a woman.

She is Charlotte, a landscape designer and now Fowler's partner but then just a casual acquaintance from her time at the BBC. She becomes an increasing presence in Hidden Nature, though, as the author struggles with the knowledge that the person she is married to is not the one she wants to be with.

“It literally happened as it did in the book,” Fowler says. “Once I'd put something down on paper I could come back to it a few days later and it was there, how I felt a few days ago. And that pattern of feeling that something was changing in me kept re-occurring. It was almost like something inside me wrote itself out and that was the moment I thought, 'I can't keep ignoring this. I have to explore why I'm coming back to this idea over and over again'.”

And while she was able to muse easily on the ability of certain plants to reproduce asexually – brambles do it and it's called apomixis – she found delving into her own sexual fluidity much more difficult.

“When you're a heterosexual, nobody makes you define yourself at all, and suddenly the moment you make a different choice …” She tails off. “Nobody asks, 'When did you know you were straight?' but everybody asks me 'When did I know I was gay?' That idea keeps playing itself out. And I was interested in that way we need to categorise and identify and [how] we put that on the natural world. So there was a strange introspective thing where here was I trying to categorise the world around me at the same time as I was struggling to categorise myself. So it was a funny whirlwind that went round in my head: I need to look at things in detail but I do not want to be looked at in detail.”

But besides Charlotte and Holiday, the two other people who figure most prominently in the book are a lesbian couple, Sarah and Ming, two of Fowler's closest friends in Birmingham. And Fowler also notes her brother's reaction when she comes out to him: he says he's been waiting 20 years to hear that news.

So was she really that surprised about what happened?

“I don't know if surprised is the right sort of term because it suggests you've been walking around not knowing yourself and somehow that's not how it felt,” she says. Instead she talks about what she calls “negative capability”, or the idea that “we all, at some points in our lives, find ourselves on one path and then go, 'Oh, I should be on that path over there'.” It isn't always about sexuality, it just happened to be in her case.

“I think what I struggled with,” she continues, “was this sense of having to explain this to people, people saying, 'You've hidden this thing' or 'You've denied this' or 'Does it mean the whole time you were married to your husband you were thinking about other things?' And that's not how it felt to me. I really loved being married to my husband and I very much love him as a person. It's just I found that my sexuality had shifted and I suppose the surprise in that was once I admitted it to myself, I just couldn't put the lid back on the box.”

BORN in Hampshire in 1977 to a GP father and a mother she describes as “a very staunch countryside woman” who kept chickens and trained gun dogs, Fowler enjoyed a rural childhood. She was educated at Bedales School, where Sophie Dahl was a near contemporary, and then studied horticulture, first at the Royal Botanic Gardens in Kew and later, on receipt of a Smithsonian Scholarship in 1998, at the New York Botanical Gardens in the Bronx. There she studied, soaked up ideas – and even had dinner with Quentin Crisp.

“He was in the New York phone book and he famously would go out for dinner or tea or lunch or breakfast with anyone who invited him. He said, 'If you're going to be famous, why not meet everyone?' So if you paid for his supper he'd go out to dinner with you, though actually he paid for my supper.

“He died three or four months later. That was a really interesting and wonderful experience. He was a great old man, and an amazing dinner companion.”

It was in New York in the late 1990s that she became involved in an urban garden project which re-used items found in skips or abandoned on the city streets, an encounter which would colour her thinking about the communitarian aspect of gardening and later see her described as “the punk rock gardener”. With the popularity of organic box schemes and allotments, it's an idea which has now entered the mainstream. Does she feel like she was ahead of the curve?

“You can't be ahead of the curve because there were people doing that in the 1960s and 1970s, in the 1920s,” she says. “So no, I don't feel like I was ahead of the curve. But I was incredibly grateful for places like New York and London and the people I met for allowing me to explore gardening in a community-spirited manner, which is very much around recycling and reusing and not spending too much money and just having a go … I think they broadened my world to allow me to see that gardening can happen anywhere and everywhere and it's something I believe passionately in.”

Fowler finished her education at University College London, graduating in 2002 with a degree in Society, Science and the Environment, and landed a job as a researcher on Gardener's World three years later. In 2008, she was made a presenter, helping front the programme until 2011. She currently writes a weekly gardening column for The Guardian newspaper and is the author of several books. None of her earlier books has featured inflatable kayaks, a marriage breakdown and a reversal of sexual polarity.

Fowler and Holiday are now divorced. She bought him out of the house and he moved elsewhere in the city. “He is very much getting on with his life and I'm getting on with mine,” she says simply, though in the book she writes movingly about the anguish she feels when she realises he can no longer rely on her unthinkingly during his regular bouts of hospitalisation. The “in sickness” bit of the marriage vow is no longer appropriate, and he and she both know it.

“I had a long and loving marriage and in order to leave that there was a lot of anguish,” she tells me. “I don't think it would have been healthy to have not acknowledged that, and it felt like a sudden amount of change all at once, which can be quite panicky.”

Seeing your wife leave you for another woman and then having the dissolution of your marriage written about would be difficult for anyone. The same is true to a lesser degree for the new partner. But Fowler says both Holiday and Charlotte were “incredibly generous and respectful” towards the project. “I feel very grateful to both of them for allowing me to just get on with my work. I feel there was a great artistic generosity on both of their parts in letting me write about them.”

As much as she can, Fowler repays their trust: if there were arguments, strains, tensions, they aren't dissected in print. Holiday is referred to throughout as H, Charlotte's surname is never mentioned and both he and Charlotte are rendered in a fairly opaque fashion.

“I think that's because when you tell someone a story you're only telling your version of it,” says Fowler. “Clearly Holiday's re-telling of the story and Charlotte's re-telling of the story would be different because it's their version. So I suppose to some extent the reason there isn't a great deal of detail about them is because I can only tell my version.”

In the natural world, as Fowler details in Hidden Nature, gender and sexuality are almost as fluid as they're now recognised to be in human life. And with Facebook now famously offering 70-odd gender options and some Government documents giving more than a binary choice too, it's a point that isn't lost on her. “I really like the fact that there's a huge broad spectrum for people's sexuality because for me, the more the merrier,” she says.

So given all that, how does she self-identify? She laughs. “I would very much identify right now as a lesbian. That's how I think of myself. Just a good old, ordinary lesbian.”

And whether common or garden, hedgerow or even canal-side matters little to her now.

Hidden Nature: A Voyage Of Discovery by Alys Fowler is published on Thursday (Hodder & Stoughton, £20)