During this hot weather period, our trees have been under stress. We ask you not to sit under our trees or enter roped off areas due to the risk of sudden limb drop. Areas including the Lower Woodland Walk, Learning Centre wildlife and picnic areas, and Copper Shelter are closed at this time.

Plant of the Month for May: a magnificent hardy cranesbill

Since way before Rosemoor became an RHS Garden, this special plant was already an established garden favourite. For more than 100 years the fabulous rich blue flowers of Geranium × magnificum have made it easy to forgive the minor shortcoming of a limited but intense flowering season.

At Rosemoor, we use Geranium × magnificum as a front of border plant in the Long Borders and as ground cover under trees and shrubs in the Rock Gully and in Lady Anne’s Garden. It is very easy-going and will grow at any aspect except perhaps north facing and in any soil except waterlogged, so it should be easy to find a spot for it in almost any garden.

G. × magnificum is an excellent plant to use for foliage contrast with, for example Sedum (Herbstfreude Group) 'Herbstfreude' as we have done on the Long Border. If you want a bit of formality, team with neatly cut spheres of yellow leaved Lonicera nitida 'Baggesen's Gold' for an attractive combination of colour and form.

We love the versatility of this geranium. In cottage garden-style planting, try growing it in association with early flowering roses, other hardy geraniums, cardoons, lupins, and poppies. For a waterside scheme, irises will make good foliage contrast and the lighter blue flowers of; for example, Siberian iris 'Cambridge' would make a fine combination.

In a shady area, flowering will not be as prolific but foliage will be reliable; the large, dissected dark green leaves turn shades of pink and yellow in the autumn. Plant with other shade-loving plants such as Geranium phaeum, ferns, Pulmonaria, Tricyrtis and Epimedium as we have done in the Rock Gully and Drive beds.

Here’s something to consider: Geranium × magnificum, along with some of the other plants we’ve mentioned, are on sale in our Plant Centre, so it would be easy to select a pleasing combination to suit your tastes in one visit. If you do, let us know what you choose and how you get on.  

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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.