Spring has come early at Scotland's most exotic garden. Sandra Dick finds Logan Botanic Garden in Wigtownshire is marking its 50th anniversary by bursting into life weeks ahead of time.

Warmed by the Gulf Stream and protected from winter’s blast, the exotic plants of Logan Botanic Garden have always defied the harshest Scottish weather to blossom and flourish against the odds.

Just 14 miles south of Stranraer, it’s where the tree ferns’ dainty fronds dance in the breeze, giant rhubarb leaves bigger than beach umbrellas create a tunnel to walk through and palm trees that could have come straight from a Californian boulevard thrive all year round.

They can cope with the sprinkling of morning frost that’s left some plants sparkling under the winter sun, says Logan’s curator Richard Baines. Instead, weeks of mild winter weather have taken a toll, creating confusion that has seen some plants burst into life and blossom weeks earlier than normal.

“Lots of flowers, including some of the garden’s camellia, are in full flower already,” he says. “That’s a lot earlier than normal.”

One variety in particular, Mary Christian, with rich, glossy, dark green foliage and flowers of dazzling bright pink petals that hug a bouquet of delicate yellow stamen, has erupted in colour several weeks earlier than normal.

“It’s in full flower at the moment and normally that wouldn’t happen [for a few weeks yet],” adds Baines.

An early spring seemed on the cards as far back as mid-December when he spotted the first snowdrops carpeting the garden’s woodland area – nearly two weeks earlier than expected.

Throughout winter, the temperature at Logan hasn’t dipped below -3.5˚c. Apart from a couple of stormy days which claimed a handful of victims, there’s been little to send Logan’s exotic residents into a terribly deep sleep.

“I walked the garden over Christmas and counted 25 different plants in flower,” Baines says. “They are definitely ahead of where they should be.

“One member of staff has been here for over 40 years and remembers ‘proper’ winters, when the whole place used to be cold and covered in frost.

“But now we can grow plants which are fairly tender and can take just a little frost and they are doing fine outside.”

For gardeners across Scotland keeping watch for the first tentative green sprout of a crocus or bluebell, this subtle shift is not great news.

A mild winter and early spring play havoc with the natural cycle of garden insects. Ladybirds may emerge from hibernation early and ready to feast on aphids only to find the cupboard bare, while a sudden cold snap could be disastrous for fragile flora.

“There can be opportunity,” adds Baines. “Milder winters mean we can grow a wider range of plants. But the opposite is that in the last two decades you have probably had more pests and disease entering the world of horticulture than in the last two centuries.

“Sudden oak death is pretty prominent, and one or two pests are much more prevalent because of the mild conditions.”

It’s a clear sign – if any were needed – of the battle faced by the natural world, one element of which was highlighted earlier this month when scientists warned that a global scientific review of insects had indicated they could become extinct within a century.

The study, by University of Sydney, found 41% of all insect species are in decline. Their loss, it warned, would spark a “catastrophic collapse” in the world’s ecosystems.

“Quite often there’s a lot of mention of birds, animals and insects, but no mention of plants,” he says, pointing out the risk to plants if there’s no insects to pollinate. “It’s always the cuddly, furry things that get the mention, but there’s a whole ecosystem out there. When one part of the ecosystem falls down, there’s a knock-on effect.”

But even if everything in the global garden isn’t terribly rosy, there’s much at Logan – one of four botanical gardens across Scotland that come under the umbrella of the Royal Botanic Garden Edinburgh – that is, at least, blooming.

Last year, more than 25,000 visitors made the journey to the Rhins of Galloway on Scotland’s southwestern tip – closer, as the crow flies, to the Isle of Man than it is to Glasgow, and further south than Newcastle.

There they breathed in the scent from more than 35 species of New Zealand and Australian eucalyptus at the garden’s Tasmanian Creek, marvelled at 150-year-old tree ferns that tower four metres tall, and the curious “filo pastry tree”, Polylepis australis, which sheds layers of its bark in a bid to capture warm air and protect itself from the cool breezes of its native Andes mountains.

In spring and summer, the mountain rhododendrons compete for attention with exotic blooms from the Canary Islands, Australia, South Africa and Chile; the 15 species of palms – some over 100 years old – evoke beach life in sunny climes rather than the southwestern tip of Scotland.

There are more than 80 species of wild flora – foxgloves, irises and wild grasses – carpeting the ground, lilies thrive on the walled garden’s pond and the carbon-neutral Victorian-style greenhouse contains South American gems rarely seen in the UK.

Where else could you find a driveway stretching a quarter-of-a-mile that’s lined with 400 cabbage plants?

“People are blown away by the exoticness of the place, it’s like an island with sea on both sides,” says Baines, who was so enchanted by Logan as a child that he went on to study horticulture and follow in the footsteps of famous plant explorers like George Forrest, trekking to foreign lands in search of rare specimens.

Later this year, Logan will be the focus for a series of celebrations to mark 50 years since it was handed to the nation.

Its roots stretch much further – the McDouall family was granted lands in the area by John Balliol in the late 13th century and built a castle. Destroyed in the 16th century, a small stump remains within Logan’s walled garden.

Fascination with exotic plants erupted in the 18th century, fuelled by explorers who ventured around the world in search of unusual species. The McDouall family’s fascination with what it found and its estate’s mild climate were a perfect match.

Soon the first eucalyptus trees in Scotland were planted in the grounds, and peat bogs dug into terraces to nurture primulas.

The estate was gifted to the nation in November 1969 and passed to the Royal Botanic Garden Edinburgh. Now, as well as being the area’s prime tourist attraction, it’s a base for horticultural study and conservation.

New plants are arriving all the time. Later this year, Baines is heading on a plant expedition to Vietnam, in search of new species and to help secure the future of others.

“Plants are disappearing very quickly there through the impact of man,” he explains.

“Many of these plants are very small and very fragile. A good example is a rhododendron called Kanehirae from north Vietnam.

"We did a survey five years ago and found the plant at Logan was the only one left in world.

"We propagated it, and circulated it around other botanic gardens.

“It’s not possible to undo what’s been done to its native habitat,” he adds. “But we can use our expertise so it’s not the end.”