Logan Conservatory, Logan Botanic Garden

Logan Botanic Garden lies near Port Logan on the Rhins of Galloway, at the far south-western tip of Scotland. The garden grew up around the ruins of Balzieland Castle. Wikipedia dates its establishment to 1869; the Gazetteer for Scotland links that year to the marriage of Agnes Buchan-Hepburn and James McDouall, and credits Agnes with inspiring her sons to collect plants from around the world and to obtain seed from well-known plant hunters such as George Forrest.

In 1969 part of the estate was given to the nation and became part of the Royal Botanic Garden Edinburgh (RBGE), which restored and enhanced the garden.

Until then the garden had no glasshouse open to visitors. One was built in 2014: RBGE describes it as Logan's first public glasshouse and as the first public glasshouse in the UK to be heated entirely by green energy sources. It was designed to house plants too tender for the open ground even in this mild climate, and to support public engagement on plant diversity, green power and climate change. None of the sources consulted names the architect or the builder.

The conservatory borrows the vocabulary of Victorian glasshouses, and RBGE describes it as both a practical and an elegant building. The sources consulted give neither its dimensions nor details of its structure.

Its technical interest lies in its heating. Photovoltaic solar panels generate electricity, and air-source heat pumps maintain the indoor environment all year without fossil fuels. Published figures differ on the temperature kept inside: RBGE's page on Logan's environmental policy speaks of a temperate 8 °C, while Countryfile magazine and Wikipedia give 18 °C.

This energy choice makes the glasshouse a teaching tool as much as a shelter for plants: the garden says it uses the building to talk with visitors about plant diversity, green power and climate change.

The conservatory holds what RBGE calls a rarely displayed collection of South African plants, chosen because they are especially sensitive to cold. They include a collection of pelargoniums.

It complements a garden known for its exotic plants, many of them from the southern hemisphere. According to Wikipedia, Logan grows about 2,500 species, 120 of them threatened, and holds the National Plant Collections of Gunnera, Griselinia and Leptospermum. Rarities include Wollemia and Rhododendron kanehirai, which is extinct in the wild. The glasshouse therefore allows the garden to show, under cover, South African plants that even this mild coast could not protect.

Logan lies about 22 km (14 miles) south of Stranraer, near the village of Port Logan on the Rhins of Galloway. The garden covers 12 hectares and enjoys a climate softened by the Gulf Stream, which allows many southern-hemisphere plants to grow outdoors.

The conservatory stands within the garden and is seen as part of a garden visit, alongside the outdoor plantings. It is worth checking the garden's opening season on the RBGE website before travelling, as the journey from Scotland's main cities is a long one.