Highly strung

The standout pop star of the year is young, gifted – and plays the harp. Jude Rogers explains why Jo

One of the most blogged-about female musicians of 2010 isn't who you might expect. It isn't Lady Gaga with her avant-garde pop. It isn't Amy Winehouse, falling out of her bodice, or Madonna, parading her latest beau around town. Instead, it's a pixie-like woman who writes songs on a harp; who is influenced by West African polyrhythms, Appalachian ballads and musical modernism; and whose singing voice - "between Björk and a handbrake", according to one critic - has divided listeners since she emerged in 2004.

Her music may be as far from conventional pop as the moon is from the sun, but Joanna Newsom is the woman wowing bloggers and critics - and doing so on her own terms. Her third album, released in the UK on 1 March, comes at a moment when every new female musician who appears to be vaguely bohemian is hailed as the next Kate Bush. Such claims are ridiculous, especially when we have the 21st century's Joni Mitchell in our midst - an artist well versed in folk, world music and jazz, who has already released two genre-warping albums, and who writes lyrics and melodies that linger in the memory. Newsom, in short, is the real deal.

Until late January, the new album, Have One on Me, was only a rumour. Then two songs were streamed without fanfare on the website of her label, Drag City: one of them a four-minute song about the Garden of Eden called "'81", the other a Fleetwood Mac-flavoured, seven-minute track called "Good Intentions Paving Company". It is these teasing hints that have sent bloggers into such a frenzy.

A few weeks later came the cover photo­graphy, featuring Newsom lying, belly-down, on a fabric-swathed sofa, surrounded by knick-knacks and lampshades, peacocks and gazelles, staring fiercely into the camera like a young Cleopatra. Where others might simply have posed like this to look alluring, Newsom's gaze is a challenge, fixing us squarely in the eyes. It's a refreshing change, in a culture where our attention is often fragmented, to find a musician who demands we engage fully with her work.

Newsom's success is entwined with the folk revival of the past decade, in which young musicians have drawn inspiration from American roots music and 1960s psychedelia. Yet her music is not retro. It may be heavy with heritage, but that is combined with a uniquely progressive vision, as her upbringing attests.

Newsom was born in 1982 in Nevada City, northern California. It was a small town full of hippies who had headed upstate when the Summer of Love started to sour. There were plenty of musicians around - including the minimalist composer Terry Riley and the protest singer Utah Phillips. Supertramp's Roger Hodgson lived next door to the Newsoms. Her parents were also musical, and although their daughter has no recollection of what drew her to the Celtic harp, she was begging for one by the age of four. After two years of piano lessons at her mother's insistence, Newsom got her first harp when she was six, and started to spend hours working through musical modes and intricate rhythms.

By her teens, while her peers were lapping up grunge and hip-hop, Newsom wanted to be an experimental composer. She progressed to the pedal harp and, at the age of 18, moved to San Francisco to read composition at Mills, the liberal arts college where Steve Reich and Laurie Anderson had studied. By 2000, however, her interest in melody was at odds with a department fascinated by electronic dissonance.

While Newsom was at Mills, two events moved her: hearing a folk number by Texas Gladden, whose piercing tone liberated her own singing voice, and a meeting with the electronic composer Pauline Oliveros, who convinced her that formal tuition was not necessary. She enrolled on a creative writing course to hone her lyric-writing, influenced by Nabokov, Whitman and Cormac McCarthy. She finally left Mills in 2002.

After that, Newsom took charge of her own destiny. She made two CD-Rs of songs for her friends - 2002's Walnut Whales and 2003's Yarn and Glue. One fell into the hands of the singer-songwriter Will Oldham, who described her as "one of my favourite storytellers" in a 2003 interview. Newsom dealt in histories and mysteries, with opaque lyrics about "disembodied and dustly wings" and freight trains that "paw at the wild, wild night". Her first album proper, 2004's The Milk-Eyed Mender, which drew on folk and blues forms, was a critical success. "This is avant-garde American music for the back porch," gushed the influential website Pitchfork, while Uncut magazine likened the listening experience to "decoding a Picasso or retracing Escher".

But although these short, soft songs had their own appeal, Newsom had grander plans. While on tour in Europe and America in 2005, she previewed some longer songs that sounded more like epic poems than dainty folk mini­atures. In 2006, they came together on Ys, a 55-minute cycle of five songs, backed by lavish orchestral arrangements.

That album put Newsom, then only 24, in illustrious company. The Beach Boys collaborator Van Dyke Parks orchestrated her grand concepts, the Nirvana producer Steve Albini sat at the controls, and the cult singer-songwriter Bill Callahan (who later became her boyfriend) provided backing vocals. In interviews, Newsom compared Ys to William Faulkner's sprawling Southern Gothic novel The Sound and the Fury. It was certainly as strange and as groundbreaking as Van Morrison's Astral Weeks or Robert Wyatt's Rock Bottom.

Ys had mainstream appeal. Newsom began to sell out concert venues such as the Barbican in London in minutes, and her audience mushroomed. After full-orchestra performances in 2007, she toured a year later with a new group, the Ys Street Band, their name a nod to Bruce Springsteen. At ease with her success, she starred in a video for the pop band MGMT in 2008, and modelled the following year for Armani. Some diehard admirers attacked her for selling out, but she invested these appearances with her own strangeness, taking her peculiar art to unexpected places.

Have One on Me is the next stage of Newsom's one-woman mission. At just over two hours long, it is audacious but plays like the necessary output of a gifted musician. It also reveals a shift in her voice - now far more refined and tender in both tone and range - as well as a tilt in her songwriting towards everyday poetry.

It opens with "Easy", the story of "my man and me", and the mystifying motions of a blossoming relationship. On "Jackrabbits", she sings of a girl who "was tired of being drunk", swinging through a room "like a brace of jack­rabbits when their necks all broke". "You and Me, Bess" takes two friends along the beach to the strain of soft horns, while "Does Not Suffice" is the record's heartbreaking closer - the story of a woman packing up her "pretty dresses" and "sparkling rings" as a relationship comes to an end. "Everything that could remind you," she sings, "of how easy I was not."

“Does Not Suffice" isn't just about love. It's about an artist who will never compromise her music or her message. This is a sentiment that we should cherish. It's not every day that the outstanding female musician of our times is also one of its most challenging.

“Have One on Me" (Drag City) is released on 1 March, 2010.