Pennard Castle ivy removal project

Dense ivy growth on the north wall is a cause for concern for the Scheduled Monument condition and the rare plants it supports. The Gower AONB team at Swansea Council has been supporting Pennard Golf Club to tackle this issue.

In 2021 Black Mountains Archaeology were instructed to undertake a 3D photogrammetric survey of the Castle. The photogrammetric survey provided a detailed record of the condition of the Castle and formed the basis for the application made to Cadw to obtain consent for the work.

The stunning 3D photogrammetric survey output can be viewed and explored online by visiting: https://tinyurl.com/35jwpnsp, or by viewing the YouTube video.

The scale of ivy incursion into the structure of the wall is far greater than anticipated. As such, herbicide treatment would have limited effectiveness and the dying stems could cause the structure to become unstable.

Instead, some areas of stonework will be temporarily deconstructed so that the ivy can be physically removed. Each stone must be replaced in the exact location from where it was taken, and the lime mortar replaced like-for-like.

Other considerations:

• Lime mortar can only be used when it's not too cold, hot, wet, or dry - so the best time to reconstruct will be autumn, spring and early summer.
• The works will require significant scaffolding to be able to safely carry out the work, and getting this to the site from the road is a logistical challenge.
• Two rare plants grow on the Castle: yellow whitlowgrass Draba aizoides has its only UK location on the south Gower cliffs and Pennard Castle, and Bristol Channel hawkweed Hieracium eustonomhas an extremely limited UK distribution restricted to a handful of sites in South Wales and North Devon.

Although the removal of the ivy will benefit these two plants in the long-term, by reducing competition for resource, steps must be taken to make sure that the populations on the Castle are not decimated in the process.

With support from Celtic Wildflowers a mitigation strategy has been developed that aims to not only secure the existing rare plant populations but will hopefully give them a boost. Seed from both plants has been collected and is being germinated and grown-on by Celtic Wildflowers in their nursery. During reconstruction, little pockets will be created in the new lime mortar and planted with the nursery grown plants.

Where necessary, all works are being undertaken with ecological and archaeological supervision, and a Scheduled Monument Consent to protect and conserve these important features.

It is anticipated that works will be completed by March 2025.