Saturday, May 17, 2014

Artemisia ‘Powis Castle’ AGM

Written by Dr John Twibell

The story behind this well known Artemisia cultivar and its synonyms. 

 'Powis Castle' is undoubtedly the best known Artemisia cultivar in the UK, if not the world. It is a short 18" (45cm), strongly and characteristically scented, silver form intermediate between typical Mediterranean Artemisia arborescens and typical A. absinthium. It rarely flowers in UK. It has often been reputed to be a hybrid, but I have seen similar but taller intermediate material in the middle east. Contrary to popular belief it was not bred or discovered at its namesake famous National Trust garden in Welshpool. The former Head Gardener at Powis Castle, Jim Hancock told me that he took the plant there with him when he took on the job in 1972. He had acquired the plant as a cutting around 1968 or 1969 from a Yorkshire garden open under NGS, but he couldn't remember where. The original plant has therefore been in Yorkshire since at least the late 1960s. The plant grew well on the Yew Tumps at Powis Castle and around 1974 the National Trust garden advisors John Sales and Graham Thomas decided to name it and sell it to promote the garden.

When I started to collect Artemisias the first actual cultivar that I obtained was 'Faith Raven', and it was not until I later got Powis Castle that I realised that they were indistinguishable. This was at the stage when I started to try to discriminate between plants scientifically by vapour profiling – using gas chromatography to separate and fingerprint the characteristic mix of vapours contributing to the scents of these plants. There are two different Artemisias in circulation as 'Faith Raven', the other version being a taller plant, more typical of A. arborescens, but Faith herself promoted the Powis Castle type under her epithet. The 'Faith Raven' saga is too long and complicated to discuss fully here but it includes a discontinuity, Faith having lost her plant one winter, and there may have been a mix-up when it was replaced. Arguments later developed between various horticultural friends of the Ravens as to which of the two versions deserves the name. She and her late husband (the academic and botanist John Raven) had collected several forms of A. arborescens during holidays in the 1960s which they brought back to grow in their garden. One of these plants came from Rhodes in 1968 or 1969. Faith believes this to be the Powis Castle type, but other evidence suggests that she may be wrong. If the Ravens brought the Powis Castle type plant back to the UK in the mid rather than late 1960's, they may be the source of the material that Jim Hancock took to Powis Castle.

Powis Castle type plant material was once featured as 'Brass Band' in a BBC TV Gardener's World programme in 1989 with Nigel Colborn showing how to trim it back in Geoff Hamilton's garden at Barnsdale. Geoff sent me some cuttings but couldn't remember where it had come from. The name suggested a Yorkshire origin to me and I made enquiries to see if it (or perhaps as 'Silver Band') was known amongst Yorkshire garden circles. None of these enquiries got anywhere and I think that the name was probably made up for the TV programme.

John Twibell holds a National Collections of Artemesia in his garden at Sidmouth, South Devon.


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