Laidback Gardener Top Pick: Armenian Cranesbill

A Neglected Perennial That Puts On Quite a Show!

I had read about this plant in various books, which is where I used to get my information in the days before Internet. However, the Armenian cranesbill* (Geranium psilostemon) didn’t strike me as being all that garden-worthy.

*Cranesbill: one of the common names for a geranium (Geranium spp.).

First, it didn’t appear hardy enough for my needs. I saw mentions of hardiness zones 5 or 6, whereas I live in the much colder zone 3. Plus, it was said to be a bit unruly looking.

And at any rate, it’s not like there was a shortage of geraniums to try. There are more than 400 species and probably as many cultivars, enough to fill a few dozen home gardens!

So, I mentally bookmarked Armenian cranesbill as, “interesting, but not for me.” I never thought I would buy this plant.

An Accidental Discovery

Then one day, I noticed an unknown geranium growing in one of my beds. It kept getting bigger and bigger, then actually very large. Soon it was covered in multitudes of magenta flowers. But what was it?

Now, I confess to sometimes losing track of my plantings. But at least the name should have been in my file. But I couldn’t find any geranium, current or past, that I had grown that even came close to what I was seeing. For a few years, I simply called it “the giant geranium” or “geranium X.”

It was during a trip to Scotland that I saw the same plant … with an identification tag. It turns out that my giant was Geranium psilostemon*. And it has since become one of my favorite perennials.

*The epithet psilostemon means “with smooth stamens.” (One has to wonder at taxonomists. They see a plant nearly the size of a small car, covered with hundreds of brilliant blooms and clearly not a run-of-the-mill geranium, yet the most striking feature they note is that the plant has “smooth stamens.”)

How Plants Get Around

How did this plant end up in my garden?

Well, I figured it probably hitchhiked a ride in, coming in as a “stowaway” in another plant’s pot. And that is, in fact, quite a common occurrence in my garden. Indeed, I often pick a specific nursery plant because an unknown plant was sharing its pot. I’ve found some great garden plants that way … but also some terrible weeds!

And my fears for the plant’s lack of hardiness proved unfounded. Whoever suggested originally zones 5 or 6 was probably assuming that Armenia has a fairly mild climate, so the plant must be tender. But they were clearly way off. True enough, the southern part of Armenia is subtropical, but its northern part is temperate, with winter temperatures down to -35?F (-37?C) in some areas. Given the way this plant seems to love cool summers, I’d guess it is originally from that area.

I’ve been growing Armenian cranesbill for over 20 years and can confirm that it’s long-lived and fully hardy in USDA zone 3 (AgCan zone 4).

Description

Armenian cranesbill is indeed a giant among perennial geraniums. Indeed, it’s probably the tallest of them all. In cool summer climates, it reaches up to 5 feet (1.5 m) in height; in regions with hot summers, it remains smaller, usually around 3 feet (90 cm).

It produces a basal rosette of deeply lobed, rather large, heart-shaped leaves 6 to 8 inches (15 to 20 cm) in diamet. But you won’t see the bigger leaves at its base for very long. Quickly in the spring, it produces a host of slender, slightly intertwined stems. They carry at regular intervals small leaves cut like a maple leaf. And of course, countless bright magenta flowers with a contrasting black eye.

In cooler climates, the plant flowers throughout much of the growing season, from late spring until frost. In my own garden, it’s one of the longest-flowering perennials: more than five months. Flowering, curiously, can last only 2 to 4 weeks in regions where hot, dry summers are the norm.

An Up and Down Plant

The plant forms a huge, fairly amorphous mound. Not that flops completely to the ground, but it’s not all that sturdy. If there is no torrential rain, it will hold up quite well, but after a thorough soaking, you might find your 3 foot (90 cm) plant is down to only 2 feet (60 cm). Then as it dries out, it rises back up, until more rain pushes it back down. So, expect a mass of greenery and bloom that inflates and deflates repeatedly. Like a lung … or bread dough!

This cranesbill continues blooming into fall. This is true even when the leaves begin to turn red with the onset of cool nights.

Culture

Armenian cranesbill adapts well to garden conditions.

It grows best in partial shade in regions with hot summers, in full sun in regions with cool summers. As for soil, any well-drained soil is perfect. In very rich soils, its stems are a little weaker; it seems to prefer ordinary garden soils to ones that are abundantly fertilized.

Good soil humidity at all times helps maintain abundant flowering, so . . . water as needed! Don‘t wait until the plant wilts.

Propagation

This geranium can be propagated by division in spring or fall or by stem cuttings throughout the growing season. The species comes true from seed and will self-sow to a certain degree. Maybe too much so in some locations. If so, thick mulch will dampen its ardor.

Hybrids (see below) are sterile and therefore won’t give rise to spontaneous seedlings. If you’re worried about the plant escaping, you could safely use those.

Uses

This huge geranium is well suited to mixed beds, especially in the English cottage style, and also forest edges.

Associations

It is in the nature of this plant to mingle with others. If you plant it with plants that are shorter, it could cover them and cut off their light supply, eventually smothering them. In fact, it manages to control most weeds on its own! But with sturdy, large-sized plants of a somewhat dominating nature, such as yellow loosestrife (Lysimachia punctata), Griffith’s spurge (Euphorbia griffithii) or tree mallow (Malva thuringiaca, formerly Lavatera thuringiaca), you can create beautiful no-care gardens. Let them duke it out on their own at first. Then, after a few years of push and pull, they usually settle in an arrangement with both sharing the same space!

Armenian cranesbill is especially very attractive when you combine it with rigidly upright plants, such as ‘Karl Foerster’ feather reed grass (Calamagrostis × acutiflorus ‘Karl Foerster’), Fine Line buckthorn (Frangula alnus [syn. Rhamnus frangula] ‘Ron Williams’ Fine Line™), and Siberian irises (Iris sibirica). They contrast beautifully with its mounded silhouette, as would just about any medium-sized shrub.

Problems

First, some good news: there are few insect or disease problems with this plant and it is fairly deer and rabbit resistant.

Control freaks probably won’t like Armenian cranesbill. It grows too quickly, is in pretty much constant movement and it’s very hard to stake unobtrusively. When you insert stakes here and there, the plant always looks like a tent you’re trying to take down.

This is why I recommend letting Armenian cranesbill grow naturally. Place it in an informal setting and just let it do its thing. If a stem gets in your way, of course, you can cut if back. If a stem flops onto the lawn, mow it. Just go with the flow.

If you want to see your Armenian cranebill reach its maximum height, plant it among shrubs that can support it rather than staking it. It will look much more natural that way.

Other Armenian Cranesbills

This plant crosses quite readily with other geraniums and has produced a handful of hybrids. They usually inherit the nonstop bloom and magenta flower with a dark eye that so characterizes the species. The hybrids all tend to be shorter, denser plants than the species, sometimes even suited to formal gardens.

The following 6 cultivars are sterile and don’t produce viable seeds.

G. ‘Ann Folkard’ (G. procurrens × G. psilostemon) is the most famous of the G. psilostemon hybrids. Without being a creeping plant exactly, its long stems do spread in all directions, blending in with the surrounding plants: a charming effect in an English cottage garden, but one perhaps less desirable in a more formal flower bed. It also looks great in a large rock garden.

The leaves give the plant extra color, since they are chartreuse yellow in the spring and lime green in summer. The flowers have the same color as those of its parent, i.e. magenta with a black center. And the bloom is also long-lasting. This cultivar requires good winter protection to survive in hardiness zone 3 (I just let snow build up on it), but is hardy in zones 4 to 9. 18 inches (45 cm) × 18 to 26 inches (45 to 70 cm).

G. ‘Anne Thompson’ (G. procurrens × G. psilostemon) is a sister to ‘Ann Folkard’ and has the same colors (green-yellow foliage, magenta flowers), but its habit is more upright. 2 feet × 2 feet (60 cm × 60 cm). Hardiness zones 4 to 9 (zone 3 under snow cover).

G. ‘Bressingham Flair’ (G. endressii × G. psilostemon) is said to be a more compact variety of Armenian cranesbill and also even more floriferous (but is that even possible?) The flowers are a bit paler and somewhat smaller. 24 inches × 16 inches (60 cm × 40 cm). Hardiness zones 3b to 9.

G. ‘Dragon Heart’ (G. procurrens × G. psilostemon): another ‘Ann Folkard’ sibling. Its flowers, the same bright magenta color as the others, are almost twice as large, providing excellent coverage. The effect of a golden carpet heavily smeared with magenta is very successful. 24 inches × 20 inches (60 cm × 50 cm). Hardiness zones 4 to 9 (zone 3 under snow cover).

G. ‘Ivan’ (G. psilostemon × G. oxonianum): This is a compact, spreading variety with extra large flowers of the same magenta coloration with black centers as the others. Like a shorter and more compact Armenian cranesbill. 12 to 20 inches × 12 to 20 inches (30 to 50 × 30 to 50 cm). Hardiness zones 4 to 9.

G. ‘Patricia’ (G. endressii × G. psilostemon) produces the same magenta-colored, black-eyed flowers as the other G. psilostemon hybrids, but they’re much larger. The large dark green leaves measure 20 inches (25 cm) in diameter and the plant grows with great vigor. 24 to 30 inches × 32 inches (60 to 75 cm × 80 cm). Hardiness zones 4b through 9.