Of all the problems to solve ahead of creating an award winning Chelsea Flower Show garden - this has to be one of the most unusual.

North Devon garden designers Annie Prebensen and Christina Williams are trying to fathom how to get donkey pats from Devon to SW3, one of London's swankiest postcodes for the biggest gardening event in the world.

"Fresh or dried," ponders Annie.

"I'm thinking we'll have to freeze it, " chips in Christina.

"Or in an airtight container..."

The pair, who have won Gold before at Chelsea, are creating a show garden for The Donkey Sanctuary to celebrate the charity's 50th anniversay.

The Chelsea Flower Show show garden for The Donkey Sanctuary to celebrate its 50th anniversary. The Artisan Garden highlights the plight of donkeys worldwide and how their health is vital for the prosperity of communities

Thanks to the generosity of a long-term supporter, the Sidmouth based charity is putting the plight of donkeys onto a worldwide stage and it's creating masses of excitement.

Nicola Ash, Donkey Sanctuary communications manager explained  that more than 70 staff have come forward to volunteer at the show.

"From the head vet to the dietician, they all just want to be involved, so I have had to organise a rota. It's a real celebration and it won't happen again, how many times do you get to celebrate a 50th anniversary?"

The ‘Donkeys Matter’ garden will use water as its central theme and will highlight how owning a donkey means access to clean, fresh water for some of the poorest and most vulnerable communities in the world.

And as you'd expect from the life of a working donkey, he won't actually be in the garden  - too busy out working -  but there will be lots of evidence of him living there.

Annie explained: "We have collected water bottles, harnesses and saddle blankets, visitors will be able to see the hoof prints and the donkey poo, we have even got fencing that has actually been chewed by donkeys at the Sanctuary.

Designers Annie Prebensen, left, and Christina Williams are creating a Chelsea Flower Show show garden for The Donkey Sanctuary to celebrate its 50th anniversary. The Artisan Garden highlights the plight of donkeys worldwide and how their health is vital for the prosperity of communities

"The idea is that the garden will be quite striking, the sound of the water dripping into the well will be among lots of little details that build atmosphere.

"We have even had little ceramic geckos made that will be crawling about. I like the idea that when the visitors look closely, they will discover more and more details."

The key design feature of the ‘Donkeys Matter’ garden is a path winding from bottom left to top right representing the many journeys donkeys carry out on behalf of communities where no ‘white van’ or family car can travel. The garden will also feature a shelter and a well with a dripping bucket.

In places like Namibia, Lamu, Somaliland and Ethiopia donkeys are used to collect water for whole communities. A donkey will often collect 40 – 60 litres of water at one time. The simple act of a donkey carrying water reduces the time required to access it, freeing children to get an education and women to be economically active.

It will showcase the charity's international outreach work that helps to improve the welfare for donkeys and, in turn, the communities that rely on them. 

Christina said: "People just assume that the sanctuary is just about saving donkeys from miserable lives but what's more incredible about the work that they do is that they are not trying to take these working animals away from people who rely on them but to instead help them to look after them the best they can."

The garden is one of the show's Artisan Gardens on Serpentine Walk, a series of gardens away from Main Avenue that have a more artistic or craft theme.

Under the trees, they gardens have a quieter, less showy atmosphere.

Annie said: "These gardens, in terms of scale and the materials used,  feel a little more relevant to what people can actually do in their own gardens."

The ‘Donkeys Matter’ garden measures 8x6metres and is suggestive of the dry Mediterranean. Bright vibrant flowers will bring beauty and colour to the harsh surroundings of the garden. Natural reclaimed stone and timber will be used throughout, providing visual cohesion and authenticity.

Key to the planting plan is cypress, lavender and glaucus pines.

But the lavender is causing a bit of worry, explained Christina, because the RHS has banned imported lavender this year due to concerns over the spread of the Xylella fungus.

They are instead having a batch brought on by specialist growers at How Green Nursery in Sussex.

"We are worrying about them all the time, said Christina.

"To have lavender ready for Chelsea is pretty early but it is being grown in glasshouses. But we have got a back up plan if the lavender isn't in flower. You have to have a contingency plan."

Annie explained that work started on site on May 8 and from 8am to 8pm 'life is over'.

Working with contractor Frogheath Landscapes, they will create a three tier garden that becomes more rugged with every step.

Annie explained: "There will be a lot of panicking people but that's the atmosphere and actually people are very friendly and help each other out."

Christina added: "When everything's going right, you feel like you rule the world and then someone steps on a plant and everything falls into despair."

Designers Annie Prebensen, left, and Christina Williams are creating a Chelsea Flower Show show garden for The Donkey Sanctuary to celebrate its 50th anniversary. The Artisan Garden highlights the plight of donkeys worldwide and how their health is vital for the prosperity of communities

The pair know what it takes to get a show garden just right. They won Gold for their show garden for the Two Moors Festival in 2010 and won Best in Category.

They went on to design the perennial planting scheme for Walker's Pine Cottage Garden in 2013.

Annie explained how judges work to strict marking guidelines and are ruthless in expectations.

"You have to be scrupulous about detail. I remember last time rushing out the the King's Road to buy a hairbrush because we realised that the grasses we had used had to be fluffier.

"We used a paintbrush to clean the paths and around the plants because the judges will just crawl all over the garden, they notice everything."

"All we can do is hope to complete the garden as beautifully as we can and fulfill the vision for the Donkey Sanctuary. If we get that right, I'll be happy," said Annie before pausing.

"No pressure then,"  she laughs.