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Hardy Geraniums

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Oh, my aching muscles...

The genus Geranium

By Marty Wingate

Visit Marty's website

It is a testimony to our love of a genus when there are so many cultivars and hybrids (let alone species) that any counting up is soon dated by the next new batch of cultivars. This is surely the case with the hardy geraniums. Their qualities, including ease of cultivation, compatibility in the garden and, most assuredly, penchant for modifying their own form, give us delight and offers endless combinations in the garden.

The genus Geranium fills many needs and niches in the garden from among its 300 or so species and, again, countless cultivars. Herbaceous or evergreen, once or continuous blooming, green, variegated, chartreuse or purple-black foliage – how could there not be a geranium for your garden?

It’s unlikely that a gardener begins by saying to herself: I want to grow lots and lots of geraniums in my garden. It is more likely that she sees a fabulous plant – say, Geranium ‘Midnight Reiter’, with its deep, dark chocolate foliage – and says to herself, “I must grow that plant in my garden.” Then she sees ‘Mavis Simpson’, its cheerful pink flowers carrying on throughout late summer, and she must have it. And then it’s the almost true color of ‘Johnson’s Blue’ flowers, the double, violet flowers of G. pratense ‘Plenum Violaceum’, and the many cultivars of the bloody cranesbill, G. sanguineum, including the pure white flowers of ‘Album’, that would look wonderful planted at the base of ‘Heritage’, a peachy-pink David Austin rose.

You see what can happen.

The many species of geranium can be found widespread around the temperate regions from the Himalayas to Turkey to the Rocky Mountains. For the most part, they are accommodating of soil, and, although most need full sun, there are a few that prefer some shade.

When we speak of hardy geraniums, we mean those of the genus Geranium, not Pelargonium (the summer geraniums) or the lesser-known, cute little rock-garden plant, Erodium. Alice M. Coats, in her book “Flowers and Their Histories” (now out of print), describes how, until the 18th century, all three of the species were lumped into Geranium. Now that they are split, their respective common names, which are translations from the Greek words used for each botanical name, have tagged along: heronsbill (Erodium), storksbill (Pelargonium) and cranesbill (Geranium). The bird-associated names describe the beaklike fruits of the plants.

Pelargonium and Geranium – the two most popular “geraniums” – are easy to differentiate by noting the irregularly shaped flowers of the former and the regular, rounded five-petaled flowers of the latter. That, and the fact that Geranium grows from a basal rosette instead of a branching single stem.

Many geraniums stay in a tidy mound. For example, G. renardii keeps its domed shape, growing to about two feet wide and one foot high. Its leaf edges are shallowly lobed – almost scalloped – and the texture is thick and quilted. I find the early-summer flowers mostly unnecessary – they are white with lilac netting, and have a washed-out appearance from even a short distance. The foliage is the better part of the show, but for those pursuing more colorful selections, the cultivar ‘Whiteknights’ is more lilac-blue.

The diminutive G. dalmaticum also stays to itself in a clump. Its leaves are about one-and-a-half inches across and irregularly lobed so as to look almost shredded, much like its larger cousin, G. sanguineum. The dalmatian blooms with dainty pink flowers in early summer. Don’t let it languish under a bolder perennial; plant it at eye level in a rockery or at the edge of a path (out of danger of foot traffic).

Most geraniums have a stronger presence, and some even mingle with neighbors, helping to weave the garden into a whole. ‘Ann Folkard’, a cultivar with the rambling G. procurrens in its parentage, is an eye-catching combination of chartreuse foliage and a long succession of shocking pink flowers that have a dark eye. Because the stems trail, the leaves and flowers appear here – between the Spanish lavender (Lavandula stoechas) and Coreopsis verticillata ‘Moonbeam’ – and there, mingling with the shrubby Clematis integrifolia.

All right, all is not peaches and cream in the geranium world. There are darker stories to tell. A highly popular wildflower in Britain is the bane of many gardener’s existence in the Pacific Northwest; it is Geranium robertianum, known as stinking robert, and by many other common names, some unprintable here. It has dark red stems, ferny leaves and small pink flowers. If you avoid pulling it because of the astringent smell or because you are unaware of its insidiousness, you will have it everywhere, because its seeds are ejected, flying hither and yon around your garden. (Give me the sweet little weed G. molle any day.)

But even sneakier than stinking robert are those ornamental plants that act weedy in our gardens. In our garden, it is Geranium endressii and its dreaded cultivar, ‘Wargrave Pink’ – all the more irritating because I bought it and brought it into the garden. Without a staff of gardeners, I have little hope of getting it under control; it appears in sun or shade, grows big, blooms profusely (yes, it is that sneaky), and then sets seed before I get around to cutting it back.

Cutting back in midsummer works well for many deciduous species, because it encourages a flush of new, clean-looking foliage and often results in another set of flowers. When I cut back Geranium phaeum, known as the mourning, or black, widow, in late June, the new growth comes back with more than the characteristic dark blotches in the sinus between each lobe; a few leaves are heavily splashed with white variegation, a bright spot in the part shade that it prefers. It’s ornamental enough for me; I don’t need more flowers.

Variegation is a matter of personal taste, and one gardener’s much-loved green-and-white plant may be another’s anathema. For example, the variegated form of the evergreen geranium, Geranium maccrorhizum ‘Variegatum’. An exciting splash of interest to some, British plantsman Graham Stuart Thomas called it ugly. Although I don’t consider it ugly, I don’t need the extra adornment for this fabulous species. G. maccrorhizum grows about a foot high and three feet wide. Its large leaves (up to three inches across) are slightly felted, and shallowly and pointedly lobed. It takes shade and, once established, dry summer soil. When brushed, the foliage gives off a piney scent.

Plant G. maccrorhizum beneath a deciduous tree, and when you’re ready to cut back the flowers (magenta or, in ‘Ingwersen’s Variety’, pink), break off a stem or two to plant elsewhere (or stick in a pot to pass on to a friend). The stems root readily. There is also a white selection, ‘Album’. In cold weather, some leaves take on claret tones. It is an all-round superb plant, and a parent of the equally fine hybrid G. x cantabrigiense (along with G. dalmaticum) with its cultivars ‘Cambridge’ (pink flowers) and ‘St. Ola’ (white flowers).

The choice of hardy geraniums is legion. Bet you can’t grow just one.

Hardy geraniums you need to know

NWGN archive published February 2003

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