A gargantuan truck fills the driveway of Tori Amos’s Cornwall home. The surrounding countryside is tranquil – verdant hills, stone farm buildings, golden crops swaying in the late August sun – but a throng of activity greets us at the home/recording studio Amos shares with her producer husband, Mark Hawley. The van and attending crew, she says, curled up on the sofa in her library, are here to collect one of her beloved Bösendorfer pianos for an impending European tour. “She’s being put in her case,” explains Amos. “Hopefully with a nice blanket.”

Amos was raised in Maryland, a Led Zeppelin-loving daughter of a minister, and self-taught pianist who would jilt both church and conservatoire to forge her own sound in the 90s: wildly original, taboo-busting piano pop. She cut through grunge’s squall, playing two, sometimes three, piano keyboards simultaneously, while wearing 7in stilettos. Her music is celebrated enough to warrant the occasional benevolent ribbing – the animated series Bob’s Burgers recently had an Amos-esque woman using lyrics about an oil spill as a metaphor for her vagina – and has been an indelible influence on today’s musicians, acknowledged by Taylor Swift, Perfume Genius and Annie “St Vincent” Clark.

Native Invader, released this week, is Amos’s 15th studio album, some 25 years on from her solo debut Little Earthquakes. She is feeling “fortunate, blessed” about this benchmark. “But writing is still nerve-racking, mostly because I’m waiting for the muses to turn up.” She has jump-started the process in previous years; a penchant for hallucinogens, for example, is well documented. “Oh, I haven’t done those in a while,” says the 54-year-old. “I’m leaving that to the youth now.”

Those 18-hour-long ayahuasca trips could be heavy going, says Amos, but nothing tested her creativity quite like the menopause. “That’s the harshest teacher I’ve met; harsher than fame. I was in the thick of it during [her 2014 album] Unrepentant Geraldines. But I’m on the other side of it now,” she smiles. “I can see possibilities again.” The “muses” saved her, but they took an age to show up. “And when they weren’t there, I was a stranger to myself.”

It was a trip through the Great Smoky Mountains, her late Cherokee grandfather’s ancestral lands, last autumn that grounded her. Trekking through the Appalachian sub-range (a stretch that bridges North Carolina and Tennessee), she imagined her “Poppa” as a boy, treading those same routes. “In that moment, we shared something; seeds were planted. I didn’t recognise them at the time, though. It was very humbling.”

Up the Creek (audio only)

Poppa’s influence runs deep on Native Invader, peaking in the urgent thrum of the album’s standout single, Up the Creek. When she was a girl, Poppa taught her about songlines – the sacred navigational paths of the indigenous folk. “We’d take walks. He’d smoke his pipe, tell me his people’s stories. There was no fanfare to it. I just drank it all in, like a weed.”

Lineage and land, then, are dovetailing influences on this album. Resilience, too, the environmental kind – climate change hangs heavy – and the psychological, both in the face of Trump-era chaos. In the US last year, while working on a song for the Netflix teen drama Audrie & Daisy, Amos experienced the poison he has spread first-hand. “I remember flying into Florida and sitting next to a woman who chanted, ‘Lock her up!’ the whole way there. Oh! Such hate,” she says. “After that, I began to see the polarities; people unfriending family members on Facebook …”

The schisms bore an unsettling similarity to Poppa’s accounts of post-civil war life, gleaned from his mother, Little Margaret, a formidable, tomahawk-wielding matriarch who had evaded the forced relocation of Native Americans by means of taking refuge in the Smokies. “I remember Poppa telling me how cousins would fight cousins, how some families still hadn’t healed, a hundred or so years later. The similarities terrified me. I cocooned myself there for a minute, and the muses weren’t coming.”

In January, Amos’s 88-year-old mother, Mary Ellen, had a stroke, “and everything changed”. Before the attack, which has left Mary unable to speak and requiring round-the-clock care, mother and daughter had spoken often. About the election? “About everything.” Doctors say it’s difficult to assess the damage, “but I believe she’s still with us,” says Amos gently. “She remembers songs, certain hymns, the Beatles’ Penny Lane. She was, is, such a believer that all things can be healed by taking a walk; that all the answers are there, in nature. To see Mary under attack from this stroke, and to see America herself, Lady Liberty, under attack – it’s a terrible parallel.”

Matriarchal power – in deities, myths, archetypes – has been a perpetual touchstone in Amos’s work, and is still present; I notice a pack of tarot-like Goddess Oracle cards on her library desk. Post-menopause, she is discovering a “different kind of fertility” in her work. She is honouring Gaia, and pulling no punches when it comes to naming the would-be architects of her destruction: “Those pimps in Washington, raping the land,” she sings on Benjamin, a track on the new album.

‘You can’t beat a bully at his own games. And I’m not talking about one particular bully.’ Photograph: Jim Wileman/The Guardian

“I think mother earth is being incredibly resilient against a government that seems hell-bent on exploiting her resources,” she says. “So she is under attack, and yet, when I walk in her bounty, I don’t get the sense that she’s giving up, or defeated. I do sense that [feeling] in people though.”

She says that paranoia and fear permeated the tours for her post-9/11 album, Scarlet’s Walk, but she’d encountered the “smell, the taste” of political influence, years before, playing to piano bar lobbyist crowds in Georgetown, Washington, throughout her teens. “I was at a very impressionable age, performing for people making huge backroom decisions about the country. That was back when [Trump’s Supreme Court appointee] Neil Gorsuch’s mother was head of the Environmental Protection Agency. Iran-Contra; Weinberger – I played through all of that.”

Remaining creative in the face of the machine, she says, is vital. “You can’t beat a bully at his own games. And I’m not talking about one particular bully here; it’s energy. You have to out-create the destruction – it’s the only way.”

But first, says Amos, the US must face its shame: its crimes against the First Nations, from Andrew Jackson’s 1830 Indian Removal Act to the bulldozers that crushed the Standing Rock protests this February. “I’m not in a position to speak for First Nation people – that’s a sacred task. But, as an observer, it seems to me that, unlike Germany, we’ve never had to really face our holocaust. Until we do that, the healing can’t begin.”

In the Smokies, she encountered locals who were oblivious to the land’s fraught history and had no idea they were inhabiting sacred songline territory. The ignorance she encountered stunned her and left her meditating on her own complicated lineage: a family tree that includes both Native Americans and Confederate soldiers.

It was Amos’s physician sister, Marie Amos Dobyns, a member of the Association of American Indian Physicians, who prompted the pilgrimage. “Marie’s a big believer in championing the voiceless; I didn’t truly understand that until Mary lost hers.” Dobyns has forged deep friendships in the Native-American medicine communities over the years, says Amos, kinships she has been generous enough to share with Amos. “I call them the ‘Seattle sweat lodge sisters’. There’s nothing I’ve experienced like [sitting in a sweat lodge with them]; you feel so nurtured, so given to. But there’s a nakedness, a vulnerability, you have to bring to it in order to receive that.”

Amos on stage in Cambridge in 1993. Photograph: Rex/Shutterstock

Vulnerability – men’s, in particular – is tackled compassionately on the Native Invader song Wings: “Sometimes, big boys, they need to cry.” Is she referencing anyone in particular here? “Oh, I see it all around me: in my marriage, in my crew.” Men can spend hours gabbing in the pub, Amos says, without ever articulating their feelings. When, I wonder, did Trump last cry? Would we all be safer from the epidemic of toxic white masculinity – Charlottesville, Dylann Roof, “fire and fury” – if men could own their fragility? “Listen, we have all heard men being called a certain female body part when they cry. And we all know the real power of that body part; talk about a multitasker! Emotional vulnerability takes bravery. Great male leaders through the ages have understood this.”

Trump’s most bilious voters – the ones who invoke God’s name with white hoods and burning crosses – are anything but brave, says Amos, and definitely not true, compassionate Christians. As a former Jesus groupie, or “recovering Christian” as her Boys for Pele-era tour T-shirts touted, Amos is uniquely qualified to know. “Some of Mary’s carers, they really walk the walk. They practise their faith on a daily basis and they glow with it. Mary had – has – that glow, that containment, too. But she’s got a fight on her hands now, to stay on the planet.”

On her impending tour, how will Amos endure the miles between mother and daughter? Will she cut things short should the worst happen? “It’s day-to-day right now,” she says, after a long, heavy pause. “I’ve been doing music since I was two and a half; it’s the thing that makes sense to me.” And yet, at her peak, Amos didn’t always make sense to her critics. In the 90s, her genius was frequently couched in misogynistic backhanders by the music press: she was a “weird chick” in Q; a “Grade-A, class-one, turbo-driven fruitcake” in the NME. “And they weren’t all men, those critics,” Amos points out wryly. But she persisted, and here she is now, 15 albums in – still touring, still creating, still defiant.