Say it with flowers. Nowhere does that more so than the RHS Chelsea Flower Show, which starts on Tuesday. The spectacle begins at the gates, as the leading floral designers Shane Connolly and Flora Starkey festoon the Bull Ring and Garden Gates respectively in celebration of the Queen’s 90th birthday.

After last year’s rally to women to submit designs for gardens, six have been selected, including the veteran Great Pavilion exhibitors Rosy Hardy, of Hardy’s Cottage Garden Plants, and Jekka McVicar, the herb supremo. Both have created gardens around curvy, flowing frameworks and, not surprisingly, both will be brimming with highly desirable flowering plants.

Jo Thompson’s communal garden for Qatari Diar, the first to enjoy a backdrop of the Royal Hospital since trees along the showground’s northern boundary were cleared to restore the view of the river for the resident pensioners, is a mass of pink and red roses underplanted with perennials in shades of chocolate and purple. And Ann-Marie Powell, who is designing the walk-through RHS Greening Grey Britain garden on Main Avenue, wants people to have to put on sunglasses to view her zingy garden.

While the ladies have opted for flower-rich designs, several of the men are tapping their inner ruggedness and have turned to landscapes for inspiration. In James Basson’s L’Occitane Garden, we can even expect to see the sun-bleached shells of a tiny snail that’s local to the Alpes-de-Haute-Provence .

Andy Sturgeon, Cleve West, Hugo Bugg and the newcomer Sam Ovens are making stylised landscapes where the look is windswept and weather-beaten — Sturgeon wants his oak to look “dusty and dirty” (hopefully, the judges will be informed that it’s intentional) — and there’s not a traditional flowerbed in sight. The familiar Chelsea grid design has also been swept aside to make way for irregular pathways through random-looking planting.

West’s Exmoor-inspired woodland garden for M&G has the most familiar palette of plants, though most of us probably wouldn’t manage to hoist the outsized boulders into our gardens.

Bugg’s garden for Royal Bank of Canada, based on wild species that grow in the rocky outcrops of northwest Jordan, is expected to be the most ambitious planting scheme seen at the show for many years. The Hortus Loci nursery scoured the world for seeds and enlisted the help of an expert grower, Marina Christopher, of Phoenix Perennial Plants, to germinate them. They have grown about 10,000 plants and expect to use 3,500.

Ovens is relying on a much smaller palette to evoke a pine-topped heathland for Cloudy Bay, which might be thinking that it’s drawn the short straw by being back to back with Diarmuid Gavin’s mechanical twirling show stopper for Harrods — though Ovens’s tranquil design, with a striking timber pavilion leading to a large pool, might be the perfect antidote to Gavin’s excess.

At recent shows, garden buildings have been out of favour, but this year some original ideas are coming through. First-timer Nick Bailey, for Winton Capital, has designed an elegant belvedere in oak and powder-coated steel that sweeps up to a 10ft-high viewing platform. Matthew Wilson’s larch and birch pavilion, in his Welcome to Yorkshire garden, has an eye-catching curved zinc roof. And the Opus glasshouse, in the Hartley Botanic garden, all sleek lines, with a bronze-toned aluminium frame, could double as a garden room.

The smaller Fresh gardens deliver the usual assortment of hard-hitting themes, which this year range from modern slavery to the regeneration of the natural world after destruction. Chelsea novice Daniel Bristow (aka Propagating Dan) says he’s not interested in themed gardens. Instead, he’s making one that’s big on novelty, with a rooftop boulder, a zig-zagging rain gutter and a new kind of neighbourly fence. There are two acoustic gardens in the Artisan category, both designed for charities and capturing the tranquil soundscape of falling water and rustling foliage.

The veteran Main Avenue designer Sarah Eberle will be darting between her ambitious Artisan floating garden for Viking Cruises, inspired by the food gardens of the Mekong delta, and the relocated Hillier exhibit in the Floral Marquee, which, at 72ft by 40ft, is bigger than most show gardens. This will be a splashy affair, with copper water chutes, gabion walls and boardwalks from which to view the 4,000 or so plants.

New exhibitors include New Covent Garden Flower Market, which is showing its cut flowers with a 10ft-high two-sided exhibit designed by Veevers Carter that promises a surprise 3D floral portrait. Expect weird and wonderful plants such as spiky purple devil shrub (Solanum atropurpureum) from Graham Blunt’s Plantbase Nursery, and blowsy clematis from Floyds.

Rhododendrons and azaleas, stars of the early Chelsea Flower Shows, but rather out of fashion of late, are in the spotlight too, as it’s the centenary of the Rhododendron Society. Millais Nurseries is creating an exhibit of rhododendrons through the ages — and, confident that we’ll be wowed by the scented blooms, it is introducing eight varieties, including some, such as ‘Bohlken’s Snow Fire’ (white, with orange centres), that are compact enough to grow happily in a large tub.

It’s not just the showground that gets into the festival spirit: many shops in Belgravia and Chelsea will be bedecked with floral displays. There’s also the Chelsea Fringe Festival (chelseafringe.com), with many free events (see panel). So everyone can join in the fun.

Chelsea Fringe Festival
Tickets to Chelsea sell out fast but most of the events in the volunteer-run three-week Chelsea Fringe Festival, now in its fifth year and staring this weekend, are free and don’t need to be booked. Head for the Inner Temple today for drop-in workshops with head gardener Andrea Brunsendorf on how to create hand-tied posies with easy-to-grow plants (11am-3pm); immerse yourself in rare and exotic phalaenopsis and vanda orchids, and taste an orchid-based refreshment, at Belgravia’s flower boutique Neill Strain, 23 May (11am-4pm); forage and then cook your foragings at Borough Market, 27 May (11am-2pm); join a weed ID walk along Regent’s Canal, Camden (various dates). Chelsea Fringe has satellite festivals too, so check out the website to see if there’s one near where you live.