In 1966, the young video artist Bruce Nauman drew a melancholy purple pastel figure sitting stiffly upright, as if boxed in, called “Seated Storage Capsule (For H.M.)”. This was Nauman’s angry response to the maligning of Henry Moore by the new generation of artists. In the postwar years, Moore’s standing as a sculptor of world importance had been rivalled only by Giacometti, but in the mid-1960s his reputation plummeted. He died wealthy and famous but his reputation has never recovered.

In Nauman’s sketch, Moore is encased in a tomb-like structure – the image wittily evokes his essential motif, shelter – to be preserved until he is relevant again. Has that time now come?

This autumn, London and Paris recreate the sculptural battleground of the mid-20th century in two historic exhibitions – Moore at Kew, the largest outdoor show of the British sculptor ever seen in the capital, and the Pompidou Centre’s L’Atelier d’Alberto Giacometti, the most comprehensive retrospective yet mounted anywhere. The comparison, when the Pompidou kicks off in October, will be fascinating. Meanwhile, the first Moore – a late, nine-metre white fibreglass “Large Reclining Figure”, with what looks like a pair of outsize jaws snapping at the nipples of its inclining torso – has been looming over the lake by Kew’s palm house since July. Today, the show opens with 28 works in situ across three acres of gardens.

The ambitious, spectacular installation confirms two things. First, Moore is an artist for whom landscape is not just an important backdrop but also an essential component of every piece, with the spaces between, in and around his figures breathing as part of the whole. Second, he is a quintessential English romantic, which is why his oeuvre appears at its most coherent and impressive in this Utopian outdoor setting. Here his work interacts with the organic forms – stones, trees, rocks, pools of water – that inform its structure.

The point is underlined by Kew’s array of carved literary inscriptions dotted through the gardens, from Edmund Spenser to D.H. Lawrence, which celebrate the pastoral vein across five centuries of English culture. This is where Moore belongs, physically and intellectually. The sculptures should stay here long-term, their effects changing with the light and the seasons as if they have taken root in the earth.

For Moore is about nothing if not roots. Security, the enfolding warmth of home, maternal nurturing are sculpted into every undulating curve and swelling contour of his work, as palpable in abstractions such as the massive “Double Oval” and “Hill Arches” here as in the iconic “Draped Reclining Mother and Baby” and “Mother and Child: Blocked Seat”. So many pieces in Kew – “Large Two Forms”, “Reclining Connected Forms”, “Knife Edge Two Piece” – are in two parts, with one element sheltering the other. “Upright Interior/Exterior Form”, of which a large version is exhibited surrounded by trees, was, Moore said, “based on this idea of one form being protected by another ... I suppose in my mind was also the mother-and-child idea and of birth and the child in embryo”.

The abundance and rural harmony conveyed in Moore’s roundness, fullness and calm solidity – nothing ever implies movement – are key differences from Giacometti, whose angst-ridden, isolated, skeletal individuals represent by contrast deracinated urban man: shivering, hungry, trembling into anonymity and non-existence. The comparison is illuminating because both artists, born three years apart – Moore in 1898, Giacometti in 1901 – emerged out of encounters with primitivism and surrealism, which each twisted into personal expressiveness: Giacometti to European existentialism, Moore to an optimistic humanism that is also a typical English mid-century compromise with abstraction.

With influences from paleolithic sculpture and American Indian totems – the inspiration for the series of “Upright Motives” here – to Picasso and Gaudier-Brzeska, Moore pushed the human body to semi-abstraction only to reanimate the figurative impulse. His fluidity and rhythm come from contrasts of shell and core, interior and exterior, vessel and hollow. By turning the body inside out, piercing it with holes which “can have as much shape meaning as a solid mass”, rotating it around a hollow case, he suggested not fragmentation or psychological collapse but vitality and the triumph of the human figure as art’s inevitable subject.

Parallels between organic and human forms underscore this elemental strength: hollows in his figures, for example, evoked for him “the mysterious fascination of caves in hillsides and cliffs”. The oneness of man and nature was his overarching theme, which Kew’s long vistas show to advantage. Moore’s supine women – “Three Piece Reclining Figure: Draped”, “Reclining Figure: Arch Leg” – suggest hill and dale as much as breast and buttock when viewed from a distance; they and bulging Picasso-like primitivist sculptures such as “Seated Woman” are Moore’s earth goddesses.

Sharing surrealism’s metamorphic transformations and biomorphic allusions, these nonetheless lack its instability, or surprise, or wit, or menace. Why? This exhibition focuses on the late work with which Moore altered postwar expectations about sculpture in public settings, so it does not include the more radical early carved pieces. But even on this monumental scale, it is clear that Moore was seeking an uncomplicated art of intimacy and reassurance. He grew up when constructivism, with its machine-age fantasies, and the dehumanisation of the ready-made were gaining ground. His art, via a language that assimilated modernism, was an attempt at a humanist response.

To the abstract sculptors of the following generation – David Smith, Anthony Caro – this made him the end of an era. Twenty years after his death, however, one can place him more clearly at the point he came of age as an artist, the 1920s and 30s, when his fixation on the mother-figure, with its implications about the creation of life and identity, chimed with many currents in British art and culture: Hepworth, Epstein, D.H. Lawrence, Virginia Woolf’s mother-obsessed To the Lighthouse, Melanie Klein, Aldous Huxley’s Brave New World.

Moore’s war drawings characteristically focus not on violence or terror but on crowds sheltering and slumbering in London’s underground stations, with the receding tunnels resembling the hollows of his own sculptures, and beyond that the safety of the womb.

After 1945, when his “Family Group” stood as a homage to the interiority of private life, the subdued equivalent to the memorials of heroism following the first world war, his mother figures evoked survival and recovery. Today, in an age when possibilities of genetics urge us to question anew what constitutes human identity and individuality, and apocalyptic threats have made environmentalists of us all, Moore’s big themes are pertinent again. It is time for him to come out of the storage capsule.

‘Moore at Kew’ is at the Royal Botanic Gardens, Kew, until March 30, tel +44 (0)20-8332 5655

Effigies

Moore’s initial attraction to Brancusi and modernism was the hope they offered of purging from European sculpture since the Gothic “all sorts of surface excrescences which completely concealed shape”. A century later, Gothic is back, allied with post-pop punk and neo-baroque, as a force in a contemporary sculpture whose aesthetic depends on just such surface excrescences to distort and warp. It is shown to stunning effect at Stuart Shave’s Hoxton gallery Modern Art, whose drab, deliberately unglamorous setting is transformed into a wunderkammer of weird, garish, kitsch, absurd, sculpted and painted heads, mostly made in 2007, for a new group show, Effigies.

Although Michael Raedecker’s acrylic and thread on canvas portrait diptych “Ah” – the initials refer to the subject, Adolf Hitler, treated with bathos like a useless clown – casts an eerie glance over the main room, and a highlight is a riveting skeleton-like full-length figure, half human, half angel, painted as if inside- out in red oil, by the excellent Matthew Moynahan, it is sculpture that holds the show.

With Jeff Koons – and behind him Warhol – as godfather, Edward Lipski’s tacky gold leaf, synthetic hair and gold chain “King III”, Terence Koh’s seductive/bleak 24-carat-gold-plated “The Golden Balls of My Youth”, Paloma Vargaz Weisz’s shimmering “Silverman” in carved limewood and silver, Klara Kristalova’s black-horned porcelain mask “Evil Ways”, all play out expensive fantasies of death. As striking here as he is at the current Venice Biennale, Canadian David Altmejd stands out for the painterly quality and luscious artifice of “Sarah Altmejd”, constructed from plaster, paint, Styrofoam, jewellery and glitter.

Quieter but also remarkable are two small bronzes by Ricky Swallow, Australian star of the last biennale, who here returns to the Catholic iconography of his childhood. “Last of the Unnatural Acts” features a ragged Mary Magdalene based on Donatello, paired with rock star and heroin addict John Phillips, depicted bedraggled in fur as photographed on Malibu beach for his album John the Wolfking of LA. Both explore a life of excess – asceticism or addiction – in the quest for meaning of all the flamboyant works here: over the top, fetishistic, extrovert and bizarre in the language and materials with which they confound our expectations of the human form.

‘Effigies’, Modern Art, London E2, to October 4. Tel: +44 (0)20-8980 7742