When I visited the Dutch capital last month, the trees were in new leaf and the very canals seemed to blossom, their houseboats decked with pots of tulips and ingenious container gardens. Later came the superb Italianate gardens of the Würzburg Rezidence; wisteria shinning up the lamp posts in medieval Rüdesheim; and the Johannisfriedhof, one of two historic "rose" cemeteries in Nuremberg, where famous citizens such as Albrecht Dürer rest among avenues of flowers.
But the highlight of our trip was a call at Limburg, where the once-in-a-decade floral extravaganza known as Floriade runs from April to October. The event is staged this year at Venlo – self-styled "region of flans, asparagus, mushrooms and beer".
To those more accustomed to Chelsea, Hampton Court or Malvern, Floriade, it must be said, is a slightly puzzling affair – a six-month World Horticultural Expo, more green Olympics than flower show, with participants from as far afield as Afghanistan, Yemen, Bolivia and Bhutan.
This lends a bombastic touch to proceedings. There's a lot of video razzmatazz and, in the manner of London's notorious Dome, quantities of showy buildings with nothing much to see in them. On the plus side, the sheer scale of the project is jaw-dropping – five themed exhibition areas set among 160 acres of lake and woodland, planted up with 1.8 million bulbs, 5,000 rose bushes, 190,000 perennials and 3,000 trees.
Floriade is first and foremost a showcase for the Dutch horticultural industry, and nowhere will you see more superb plantsmanship – perfectly grown trees and shrubs, immaculate cloud-pruning and resplendent displays of massed bulbs.
Like so many garden festivals, Floriade is also a development project. In its future guise as a business park, the lofty entrance arch (reminiscent of La Défense) will one day house "innovative sustainable agribusiness", while the carbon-neutral Villa Flora exhibition hall will become the "greenest office block in the Netherlands".
With such a vast site, it's impossible to see it all in the meagre morning that most tours allow. So be ruthless – ignore the official guides and hone in on the highlights.
The largest indoor flower exhibition in Europe, the Villa Flora definitely falls into this category. Eye-popping blooms dangle from test tubes and spill from airborne shopping baskets; flowery tops spin on carpets of moss; climbers romp up lamp posts and twist among chandeliers. In contrast, single orchids are exquisitely displayed in a white, cloister-like corridor. It's an impressive spectacle.
To help you appreciate how essential the colour green is to our wellbeing, the Living Pavilion merges inside and out, and features a dining table overflowing with herbs and a fireplace "ablaze" with flowers.
There's family fun to be had, too, in the Education zone's Bee Garden, where you can work out how successful you would be as a bee by selecting flowers on the basis of their pollen levels. Also in this area is a spectacular tropical greenhouse, designed by CenterParcs and surrounded by a maze-like bamboo garden.
In the Israeli Hidden Garden, based on the Seven Species (two grains and five fruits mentioned in the Bible), you'll find gaunt vines recalling the Jewish menorah, and stark red rocks symbolising the six points of the Star of David. These features lend the garden a seriousness and tranquillity that really set it apart.
Among the many fascinating exhibits about trees, perhaps the most intriguing is the row of trees suspended in sacks like giant hanging baskets. Ever wondered how trees arrive safely at Chelsea Flower Show? Now you know.
With sustainability a major theme, the sponsored NL garden is the place to stock up on design ideas – from inventive vertical planting schemes to a snazzy way of concealing bins, and a car port that doubles as a charging point for an electric car thanks to its solar-panel roof.
Sustenance can be found at the World Show Stage area, with its food stalls and show pavilions from all corners of the world. Highlights here include the exuberant Indonesian pavilion, a conceptual garden by Korean artist Jihae Hwang (his lavatorial garden stole the show last year at Chelsea), a traditional Chinese garden and the Spanish Pavilion, fashioned from outsize coloured pencils.
But for me, the star of the show, and an antidote to all the glitz, was a circle of fruiting trees, which were in blossom when I visited. Each corresponds to a phase of the Celtic lunar calendar and denotes a character type. I discovered my family includes a "stubborn sensitive" (fig), an "independent fighter" (cypress) and a "lusty pioneer" (ash). It's good fun and a beautiful piece of planting.
There's plenty to entertain non-gardeners, too, with a gondola ride and all kinds of bands and street theatre. And after a hectic day at Floriade, you'll be more than grateful for your luxurious ship as you float on gently down the Rhine, enjoying water meadows full of wild flowers and orchards heavy with blossom, without having to walk a single step.
Three cruises that visit Floriade
AmaWaterways offers this seven-night Vineyards of the Rhine and Moselle cruise, with a visit to Floriade, departing August 19, 2012. From £1,395pp, including entry to the show but excluding flights. (0808 223 5009; www.amawaterways.co.uk)
Scenic Tours offers a 15-day Jewels of Europe cruise from Amsterdam to Budapest, with a visit to Floriade, departing between May and September 2012. From £2,695pp, including flights and entry to the show. (0161 236 2444; www.scenictours.co.uk)
The River Cruise Line offers an eight-day Rhine In Flames cruise from Dover to Cologne, with a visit to Floriade, departing August 7 and September 4 and 10, 2012. From £859pp, including entry to the show. (0844 544 6437; www.rivercruiseline.co.uk)
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