Box Hedging feature in the plans of eight gardens including Charlie Albone’s ‘The Husqvarna Garden‘ but many clipped alternatives to box, such as yew and bay are also used.
Oak trees are a predominant feature being used by designers such as Cleve West. Barter said box had a "tricky future", while oaks were "under threat" from pest and disease but designers were using them in a "subliminal" message to the public about their importaance.
Barter added that peonies are a design favourite this year and roses feature prominently. Other popular flowers include alliums, achillea, foxgloves, irises, lavender and geum.
Ferns are proving popular with some designers, while others have turned to plants such as Bracken and Horsetail to add beauty to a garden.
Barter added that he hopes Jordanian and Mediterranean plants from seed grown for Hugo Bugg and James Basson "will tickle the fancy of seed merchants and bring new plants to cultivation".
He said: "Dramatically exotic peonies are set to be leading actors this year and have proved to be an interesting and exciting plant choice for designers such as Matthew Wilson and Hay Hwang. Roses are also popular, with Jo Thompson featuring the beautiful bloom. Rose-related enquiries topped our RHS advisory list this year and are much loved by gardeners.
"Pastel predominates as a colour, but there is a healthy amount of green seen in many of the gardens, with rich plantings of ferns. Ferns don’t tend to be readily stocked in plant centres, so I wonder if this will now change as people are inspired by what they see at the Show.
"A real point of interest is that so many oaks feature in plans – an iconic UK tree at a time when so much ash is suffering and oak processionary moth is moving into the countryside and tree disease Xylella fastidiosa, albeit one adapted to olives, is spreading in Europe – a subliminal concern for this tree perhaps?
"Based on our Gardening Advice service, our members may well be quite surprised to see some weeds in RHS Chelsea gardens – but everyone knows a weed is just a plant in the wrong place."
He added: "Jekka McVicar’s herbal lay for example, reminds me of some research RHS and Reading University conducted where low growing plants that are not grasses were used as permanent ‘turf’. A ley is defined as temporary pasture, often nowadays including forbs such as milfoil and chicory. Indeed why can’t gardeners grow leys as a kind of temporary lawn/wildlife/herbal border – they are often raised from seed and are low cost and wildlife friendly."
David Austin Roses launches the new English shrub rose, ‘Roald Dahl’, which is named in honour of the world’s number one storyteller and marks 100 years since his birth as part of the official Roald Dahl 100 celebrations. Appropriately the blooms are peach-coloured, acknowledging Roald’s ‘James and the Giant Peach’, which was his first literary success in 1961. The ‘Roald Dahl’ rose is a remarkably free-flowering rose with the blooms produced almost continuously.
The ‘Princess Charlotte’ chrysanthemum by Deliflor is launching in honour of the royal baby. Other new plants include Acer ‘Moonrise’ by Hillier Nurseries, hosta ‘Smiling Mouse’ by Hogarth Hostas, vibrant and deep red ‘Cherry Kiss’ by Millais Nurseries.