Hardy geraniums are not my favourite plants. They can be easy to grow, reliable, flower for ages and are very useful. But they are a bit like potatoes (I apologise for being anything but enthusiastic about spuds while being in Ireland) – they are essential but I can’t really get very excited about them and would rather have something else on the plate. But even I eat spuds sometimes and so I always have a few geraniums here and there. Now there are lots of good geraniums and they make good ground cover. And there are a few stars such as the exceptionally good ‘Rozanne’ which is a plant that every garden should have for its large blue flowers month after month.

But, despite those gorgeous flowers, my favourite geranium is a bit less trendy and has never had anything like the publicity and accolades. Geranium pyrenaicum is a European native that is found over much of the continent and even in southern England. The mauve flowers are produced over many months and it is known as the hedge cranesbill. It is not known if it is truly native to the UK because it was not known there till 1762. There are different colour forms and the white ‘Summer Snow’ should be a winner but I will never grow it again. It has one good feature that all white-flowered plants should have – it drops its petals before they turn brown, but somehow the small size of the flowers seems more of a problem when the flowers are white and it seeds like crazy. It is easy to mix with other plants but I just can’t take to it.

But the bright lilac purple flowers of ‘Bill Wallis’ are a different matter entirely. First, that colour. It is gloriously cheerful and bright without being too strident. The flowers are about 1cm across. As they age they can become slightly more blue and as the sun sets the colour intensifies and seems to glow each evening.

It is a perennial, but shortlived, and it sets prolific seed. In theory this means it can be invasive but I rarely find that it is a nuisance*. It will flower in the first year from seed if sown in spring.

It is also hardy and will grow in sun or shade and in any soil – clay or sandy, moist or dry. You may find it seeds into gravel or in walls. Another big plus is that deer and rabbits seem to leave this alone. And I have rarely found mildew on it.

The leaves are rounded and form a low rosette at first and then many-branched stems thrust up to 45cm high. In the second year flowers start to open in April and the plant can keep on flowering till October. By then there will be dead stems of course but they can be sheared off and more will pop up. Sometimes plants flower themselves to death but the seeds are flung around and will produce more seedlings. The seeds germinate over an extended period and some will germinate in summer or autumn while others will wait till spring – handy if you want them, annoying if you are trying to get rid of it!

All geraniums are sociable and enjoy nuzzling around other plants in the border and this one is no exception. It is usually about 30cm high and 45cm across but, if it has a willing neighbour it will hitch a ride and get up to 60cm in height. Because it seeds, it will soon create some exciting and unplanned colour combinations but they all work! Seeded into a clump of yellow day lilies it adds zing and it is  perfect under pink roses, through lavender or over blue or yellow hostas – the list is endless.

Because of its straggly habit when in flower, you probably won’t find this in garden centres but seeds are widely available and offer the best way to get this friendly little plant in your own garden.

Geoff’s rating

10/10

Garden rating

9/10

* I never find this plant seeds so much that it is a nuisance but some people do so I just want to warn you.

geranium pyrenaicum bill wallis