During this hot weather period, our trees have been under stress. Due to the risk of falling branches, we ask you not to sit under or use benches under our trees or enter roped off areas.

August plant of the month

A spectacular Mediterranean shrub with delicate late-summer flowers deserves a spot in any sunny garden

The Laboratory building provides one of the most iconic views of Wisley. Beside its central door is a large shrub that comes into its prime in late summer - Vitex agnus-castus f. latifolia otherwise known as the broad-leaved chaste tree.

It is the lavender-blue flowers that make this shrub special, popular with butterflies too. Small, tubular two-lipped and fragrant, the flowers are borne at the end of the branches in a terminal spray. It’s reminiscent of Buddleja. The leaves are palmate – like a hand – with five or seven leaflets, and these too are aromatic. It’s rather elegant and in its west-facing location it is thriving. In its native Mediterranean regions such a specimen might reach 4–8m though 2m is more likely in Britain. They aren’t too fussy about soil type but do like sun and shelter from the cold.

To demonstrate the versatility of this plant, we also grow it on Battleston Hill and in the Mixed Borders, where the flowers and foliage add grace and structure to the plantings. You might spot a pink-flowered Vitex agnus-castus ‘Rosea’ and a white-flowered form known as alba ‘Silver Spire’. They’re all beautiful, and a worthy addition to any garden.

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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.