Joni Mitchell has a problem. She wrote too many love songs.

This was not always a problem. Songs about love made her one of the greatest living songwriters. But when she sat down with the Alberta Ballet to create a performance on the theme of love, she was spoiled for choice, unwilling to compromise and overwhelmed by the scope of her own romantic oeuvre. She started with hundreds of her own songs, and needed about a dozen. She could not get any lower than 40, which is well beyond the time limit of any normal ballet.

"She couldn't whittle it down.... She was distraught because she tried. She worked so hard," said Jean Grand-Maître, artistic director of the Alberta Ballet, which has postponed the show that was due to open in May, replacing it with a tribute to classic Hollywood musicals. No new date is set.

"It was my mistake, because I should have said to Joni, you know, do the ballet, create it in your mind, take all the time you want, and when you're ready, let me know, and we'll put on a production. And what I did instead was give her a timeline, that we're going to premiere in May 2014, and we're going to start creating the ballet in January 2014. This timeline is what didn't work. For an artist of her profound capabilities, I should have just said to her, 'Go dream the ballet,'" he said.

Jukebox musicals based on popular music, like We Will Rock You, Mamma Mia! or Jersey Boys, are an established genre, but jukebox ballets are a rarer and newer thing. Ms. Mitchell was a pioneer of the style in 2007 when the Alberta Ballet staged The Fiddle And The Drum, a show about war in Iraq and the environment, with dance set to many of her songs. It toured all over the world.

Other shows by the Alberta Ballet followed on that success, under the guidance of Mr. Grand-Maître, with ballets set to the music of Elton John, Sarah McLachlan and k.d. lang.

But a lifetime retrospective of Canada's folk music icon, set to ballet, is even trickier. The theme of love was meant to bring focus, but it also introduced its own awkwardness, because it can mean so many different things, so many of which she has written about, from love for the child she gave up for adoption, to romantic love, to her longing for California while in Paris.

"We talked about how today in the world people seem to have lost the perception of love; there's so much aggressivity and fear and violence and miscommunication.... It would have been an exploration on the themes of love today, and how we've forgotten to love, and how love is abandoned in the modern world, and what we need to do to reconnect as people," said Mr. Grand-Maître. "At first it was a wonderful project. Who has written more profound songs on love and relationships than Joni Mitchell, and all aspects of love, from family love to love affairs?"

It also coincided with Ms. Mitchell's work with a record company on a four-disc set of remixed and re-orchestrated songs on the theme of love, he said. But when she started to pick and choose, working with Mr. Grand-Maître in both California and British Columbia, it was like trying to catch the wind.

The tentative song list, drawn from albums including Blue and Songs of a Prairie Girl, included such obvious classics as A Case Of You ["You're in my blood like holy wine..."], Both Sides Now, and The Only Joy in Town ["The Botticelli black boy / With the fuchias in his hair / Is breathing in women like oxygen / On the Spanish stairs."]

She worked on the project for a year, sequencing songs in a way that makes musical and poetic sense; editing the libretto, or script, based on her lyrics; and designing the sets, including a contemporary video installation.

But picking just a dozen songs proved too difficult, and when Ms. Mitchell's 70th birthday passed last month, it became clear the deadlines would not be met. A new one has not been set.

"There's no real failure. It's not a writer's block. It's more that the theme we're exploring, what Joni wanted to do, this ballet created and inspired by the theme of love, has for her so much meaning and it's such a rich subject that she's unable to squeeze it into 12 songs and be satisfied with it, and that's something I absolutely respect," said Mr. Grand-Maître.

"It's absolutely understandable. You have to imagine Margaret Atwood or Emily Carr - that's the stature of Joni Mitchell anyway, in my mind - and you're asking them to say [which songs to choose], and in one of the last phases of their career, everything becomes even more important, what they say and what they release as works of art. So for her, this was an extremely important project," he said. "The concept was so stunningly beautiful and so human and so touching and so real that I certainly hope it will happen one day."