Fresh ideas from the Chelsea Flower show 2015

1 Water, whether used in rills, streams, jets, cascades, "rain curtains", formal pools, wells or natural swimming ponds, featured in most of the show gardens at the Chelsea Flower Show , although not every designer used it well. Those who did included the seasoned Japanese designer Kazuyki Isihara (artisan category) and Dan Pearson, whose Best in Show Garden, with its giant boulders, trickling streams and air of leafy tranquillity, took its inspiration from the Victorian designer Joseph Paxton's ingeniously-engineered Trout Stream at Chatsworth House, the stately home of the Duke and Duchess of Devonshire. There's a nice Irish connection to this garden, as Pearson told me that the royal ferns (Osmunda regalis) and moss used in its construction came from Lismore Castle in Co Waterford, also owned by the Devonshires. Both Pearson and Isihara's Chelsea gardens use water in a way that's musical rather than jarringly noisy.

2 Stand-out flowering plants. Long-flowering and versatile, perennial geums in shades of blood-orange and tangerine such as Prinses Juliana', "Totally Tangerine", "Fire Storm", "Flames of Passion", "Gimlet" and "Sea Breeze" were everywhere at this year's Chelsea, pepping up the planting plans of many of the best show gardens as well as the nursery stands in the Great Pavilion. Roses also made a return to many of the main avenue show gardens, including Pearson's naturalistic garden (the scarlet-thorned Rosa pteracantha and the eglantine rose, R. rubiginosa), the romantically nostalgic M&G garden (fragrant pink Bourbon "Louise Odier" and purple-flowering, shrubby "Chianti"), and the dreamily atmospheric "L'Occitane" Show Garden (shrubby, double-pink "Yolande d'Aragon" ). Other Chelsea plant stars included several exciting new introductions, such as the gorgeous American-bred Salvia "Love and Wishes", compact, starry-eyed Camassia "Maybelle" (a beauty) and long-flowering, properly perennial, Antirrhinum "Pretty in Pink".

3 Native or naturalised species more commonly seen as field boundaries, such as the lovely and yet inexplicably underrated hawthorn (Crataegus monogyna) and field maple (Acer campestre), featured as informal boundary hedges in several of the large Chelsea show gardens, where they looked right at home. Similarly, many designers successfully used these species as standalone specimen trees, including the Rich brothers in their impressive "Cloudy Bay" Show Garden. In another nod to the vernacular use of native/naturalised trees, designers such as Pearson, Andrew Wilson and Gavin McWilliam used magnificently statuesque specimens of pollarded willow, while Chris Beardshaw's garden also featured pollarded field maples to sculptural effect.

4 The British Ecological Society's "Plants and Soils Working Together" exhibit in Chelsea's Great Pavilion is timely, given that 2015 is the International Year of Soils. Using a nattily compact, mobile microscope attached to a laptop, Chelsea's visitors were encouraged to examine the complex relationship between plants and soil organisms, and how they are vital to soil health. For more details on the International Year of Soils, see fao.org/soils-2015/en/

5 One of the things that I love about the Chelsea Flower Show is that it's such a wonderful showcase for so many ingeniously designed garden products, This year I discovered the Spiral Plant Support, a light-weight coil of metal that can be easily wrapped in a supportive spiral around plant stems, perfect for those of us who dread the painstakingly laborious process of staking plants. See Babyllon Garden Products (babyllon.co.uk)

6 Another quirky garden product was unveiled by Sneeboer, the Dutch company well-known for its innovative, well- made range of tools. It has designed a transplanting trowel with a twist; neatly cut into one edge of the stainless steel blade is a bottle opener. Perfect for summer picnics in the garden (£33.30, sneeboer.com)

7 Multistemmed specimen trees have long been a classic element of many a Chelsea show garden, giving height, depth and a sculptural element to planting schemes while preserving views. However this year's Chelsea Flower Show stands out for the diversity of species used in this way, including the golden-flowered Kolreuteria paniculata "Golden Rain", Ficus carica, Crataegus prunifolia, Amelanchier lamarckii and the evergreen Osmanthus x burkwoodii. In the case of the latter, which was used by designer Marcus Barnett in his De-Stijl-inspired Telegraph garden, the trees were charmingly underplanted with the moss-like Sagina subulata.

8 Ornamentals aside, this year's show reminded gardeners of the many different uses of plants. Did you know that the common herb lovage was commonly used as a flavouring in beer, or that sweet chamomile is used to flavour alcoholic drinks such as vermouth and Benedictine? Their stories were highlighted as part of Sparsholt College's excellent "Hopcycle" exhibit in the Great Pavilion, while The Royal College of Pathologists' intriguing exhibit explores how derivatives of many different plants are used in modern-day medicine.

9 Time to loosen up. While formal topiary specimens of yew and box clipped into neatly geometric shapes will always be a feature of Chelsea gardens, this year some designers opted instead for plump, spreading mounds of the handsome evergreen shrub Pittosporum tobira instead. Others, such as Pearson, used topiaried box unconventionally, clipping it into bulging, asymmetric, organic forms.

10 Kent-based Dyson's Nursery hasn't exhibited at the Chelsea Flower Show for some time, so its return to the Great Pavilion this year was a great treat for lovers of salvias, that amazingly versatile and long-flowering genus of plants which add so much to a summer container or border. The nursery's mouthwatering Chelsea display included the daintily compact Salvia "Dyson's Joy", one of several varieties raised by William Dyson himself. For more, see dysonsalvias.com

11 Not only are they often visually unlovely, but front gardens paved over into parking spaces contribute to the problem of urban flooding and pollution. As part of its campaign to raise awareness of this issue, the RHS gave novice designer Seán Murray, winner of BBC's Great Chelsea Garden Challenge, a spot on Chelsea's main avenue this year with the brief of designing a car-friendly, biodiverse space. The resulting show garden is a thoughtful mix of permeable surfaces and plants aplenty, proving that gardens and cars can mix. See rhs.org.uk

12 The use of cutting-edge design and modern building materials. Several of this year's Chelsea show gardens shine out in this regard, including Spanish-born designer Fernando Gonzalez's "Pure Land Foundation Garden" in the Fresh category, a wonderful Gaudiesque space of fiery planting and undulating, white walls. Inspired by the work of the British-Iraqi architect Zaha-Hadid, the latter are moulded out of a versatile, resinous material known as Jesmonite, using state-of-the-art technology borrowed from the aerospace and film industry. Howard Miller's brilliant "Dark Matter Garden for the National Schools" features a covetably beautiful, giant concrete planter by Urbis Design (urbisdesign.co.uk), acid-aged steel walls and a lattice of rusted steel rods engineered into individually unique contours. Meanwhile, the Rich brothers' "Cloudy Bay Show Garden" on Chelsea's prestigious main avenue features a battery-powered, timber-and-glass garden "shack" that runs on steel rails, allowing it to be repositioned in different sections of the garden at whim. Very 21st-century . . .

13 The importance of fragrance in a garden. From the rich, heady scent of hyacinths, irises and roses in the Great Pavilion, to the aromatic L'Occitane Show Garden (above, left), nature's perfumes wafted through Chelsea's showgrounds. Yum . . .

14 The rockery's return to fashion . . . just maybe.