Hazel Southham, journalist, broadcaster and author wonders at the vision of Augustus Smith to create and protect the heavenly corner that is Tresco Abbey Garden.

 Vision. That’s what Augustus Smith had. That’s what I think to myself as I sit at the top of Tresco’s Abbey Gardens and survey acres of flowers and trees, with the sun sparkling on the sea just beyond them.

Who, in their right mind would consider planting such a garden? I know the Victorians were enterprising types, but surely there are limits? Howling gales blow into the Scilly Isles in the winter and, as you can see from all the people wearing hats on the boats, it can be distinctly breezy in the summer too.

Wind isn’t great for plants or trees. Just picture in your mind a hawthorn tree blown into a 90-degree angle by relentless winds. Add to this that here on Scilly the wind carries sea salt inland and any plant grown hereabouts, you would think, would therefore be in for a miserable time of it. Salt burns most plants except for the astonishingly hardy ones that are adapted to cope with it and thrive on our shorelines.

But Augustus Smith, who created the gardens in the 19th century, knew a thing or two about hedges. He knew that if he was going to create the garden of his dreams – indeed if he was to protect any plant at all – he’d have to build hedges to shelter them. So he did.

The shelter belt of trees that surrounds the gardens is 200ft deep in places. Yes really, 200ft. There are an astonishing 60,000 trees growing around the gardens.

According to head gardener, Mike Nelhams, 80 per cent of the plants that grow in the world-famous gardens wouldn’t be there without the hedges.

‘The gardens wouldn’t be here without the hedges,’ he says. ‘It would always look burned and broken because of the effect of the salt.’

The wind comes up to the hedges and goes over the top of them, as they protect the plants within. Because of this, the hedges also create a micro-climate. Mike says that, within the gardens it can be 15 degrees when outside the shelter belt on the rest of the island, it is below freezing. So he can be wearing a t-shirt in the garden while other islanders are wearing their thickest winter coats and hats.

It seems extraordinary that hedging can do so much.  But all you have to do is sit still for a while in the gardens and look about you, to see just how much of a difference Augustus Smith’s hedges have made.

There are plants here from all five floral regions of the world that lie within the Mediterranean – that’s to say anything from 30 degrees to 45 degrees on the map.

There are New Zealand tree ferns, echiums from South Africa, aloes, proteas and banksias. You’d have to travel half the world to see these in their original habitats. But here, on a rocky outcrop off the south coast of Britain, they are growing happily. Hedging really is a wonderful thing.