There are several deep valleys cut into this plateau such as Lamorna on the south coast, where sufficient shelter from the weather is gained for trees to establish and grow. The shelter of these valleys and the mild climate gives Penwith a flora not seen anywhere else in the UK. Penzance's Morrab Gardens is able to grow bananas. Penwith also contains an artificial lake, Drift Reservoir, which is located approximately 3 miles west of Penzance. In addition to Penwith's status as a Heritage coastline, west Penwith, an area of 90 square kilometres, is considered an Environmentally Sensitive Area. Penwith lies within the Cornwall Area of Outstanding Natural Beauty (AONB).