The Bloomsbury group’s habit of non-binary bed-hopping has frequently attracted more attention than the artworks they produced. But in their Vanessa Bell retrospective, the MK Gallery has steered blissfully clear of salacious tittle tattle. Thankfully, this allows one to focus on Bell’s paintings and designs rather than her complicated domestic life.

What a feast! Congratulations are due to the National Gallery for its latest blockbuster After Impressionism: Inventing Modern Art. Such a superb collection of modern masters is unlikely to be assembled again under one roof, so this is a once-in-a-lifetime, must-see exhibition.

Edgar Degas is famous for his depictions of ballet dancers. His drawings, paintings and sculptures of young girls clad in the uniform of the dance are signs of an artistic obsession that spanned a remarkable artistic career. One work in particular – a sculpture of a young ballet dancer in a rest position – cemented his reputation as a pioneering spirit, unafraid of provoking controversy in the pursuit of perfection.

“Gauguin was undoubtedly self-obsessed” begins the National Gallery’s latest dead cert blockbuster, as it cheerfully hijacks a de facto series begun next door at the National Portrait Gallery.

Soon after his death, Van Gogh’s reputation as a tragic genius was secured. Little has changed in the meantime, and he has continued to be understood as fatally unbalanced, ruled by instinct not intellect.

In the autumn of 1892 Émile Bernard wrote home to his mother that, following the summer decampment to Pont-Aven of artists visiting from Paris and further afield, there remained "some artists here, two of them talented and copying each other.

Some 50 portraits by Paul Cézanne – almost a third of all those the artist painted that have survived – are on view in this quietly sensational exhibition. Eye-opening and heart-breaking, it examines his art exclusively in the context of his portrayal of people for the first time.

Art exhibitions hardly seem comparable with battery farming, and yet just as our insatiable appetite for cheap meat gives rise to some troubling consequences, so too does the demand for definitive exhibitions that require vulnerable works of art to be shipped around the world. And so it really is a cause for celebration that an exhibition exploring Eugène Delacroix’s influence in the 50 years following his death maintains its focus, argues its case and thoroughly immerses us in his work, without actually showing us any of his best known paintings.

Painting the Modern Garden explores the interstices between nature and ourselves as revealed in the cultivation of gardens, that most delightful and frustrating of occupations, and an almost obsessive subject for many artists. About 150 paintings from the 1860s to the 1920s, gathered together from private and public collections in North America and Europe are on view, amplified by letters, plans, documents, photographs and illustrated books on horticulture.

Walking into this exhibition is a bit like walking into a great forest. The dark green walls are hung all around with paintings of trees; we look up through branches that spiral dizzyingly skyward, while the upwards sweep of vast trunks seem relentlessly, tangibly full of life. Some of these paintings verge on abstraction, the forms of tree trunks simplified and reduced to an arrangement of planes, with spatial recession represented entirely through colour.