The Wollemi Pine was thought to have died out millions of years ago
What is believed to be the world's most northerly grove of a Jurassic tree has so far survived freezing temperatures.
Wollemi Pine - thought to have died out two million years ago before being discovered in Australia - were planted at Inverewe Garden last June.
National Trust for Scotland gardener Kevin Ball said the Highlands site had experienced its coldest temperatures in more than 30 years.
He said -7C was the lowest recorded at the garden so far this winter.
Mr Ball added: "The Wollemi Pine was only discovered in 1994, so we're learning about it all the time.
"However, evidence at the moment suggests it can tolerate the cold more effectively than its Australian origins would suggest and can survive temperatures as low as -12C.
"Wollemi Pine can live up to 1,000 years and we're hoping this will be the case for our sturdy little saplings."
The trees at Inverewe were cultivated from those found to have survived in a single isolated grove in Australia.
The discovery of the pine in 1994 caused a scientific sensation, and prompted the Australian government to protect the site where it was growing.
Park ranger David Noble found the trees in the Blue Mountains, west of Sydney.
The species was thought to have been extinct for at least two million years. The only previously known examples were fossils which were 175 million years old.
Eight Wollemi Pines were planted at Inverewe.