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Plant to know: Geranium macrorrhizum


I take no pride in admitting that this Plant to Know, which is one I now hope to never be without, is also one that for a time I wrote off as just another garden plant. But that’s a problem with a plant that isn’t particularly flashy and that you rarely need to visit. And in a nutshell, that’s Geranium macrorrhizum. It just does its thing and it does it well.

On its own, big-root geranium, as it’s commonly known, is completely underwhelming. Sitting in a nursery container it looks like a geranium that’s not doing much of anything. But there’s a warrior hiding under that somewhat ordinary exterior. Pair it with a few sister plants and you will create an army of plants that will create a tall groundcover (to me anything over 4 inches tall is a tall groundcover) that will shade out most nasty invaders. And this army is willing to fight this battle on nearly any turf. I grow it in full sun, which is not all that impressive, but also in dry shade, even under thirsty cedar trees, which is worthy of a plant military commendation.

Geranium macrorrhizum in the Each Little World garden
Geranium macrorrhizum and friends fill a hillside at Linda’s garden. Each Little World photo

Because of this admirable performance in almost every condition I’ve thrown it in, Geranium macrorrhizum is not just a plant you should know, it’s an all out garden all-star in my book. And I’ll fully admit that I didn’t pay it much attention until I saw it planted en masse in Linda’s garden. It’s just so damn good.

But I want to be clear about what you’re getting when you get into a relationship with this plant. You’re getting a plant that you won’t notice a lot of the time. In fact I can almost guarantee you’ll forget about it until one day you realize how tidy an otherwise messy area might look. Technically it spreads, but in my garden it doesn’t really move along until I divide it, which I can do as frequently or infrequently as I like, it seems. I got most of mine from my sister-in-law who let me dig out about 10 chunks out of her garden when she was revamping a bed. I now have it on both sides of my driveway in fairly long stretches and along the bank of the creek where it holds off advances by nasty invaders like garlic mustard weed. I’d like to bulk up its presence along the driveway (if it lined my entire long driveway that would be perfectly acceptable to me), so when I have some time I’ll do a little dividing this spring.

Geranium macrorrhizum
These bigroot geraniums grow in dry shade under cedars on the edge of my driveway, getting pummeled by snowblowers and the occasional car, but look no worse for the wear.

As for care, well, I don’t know what to tell you. Other than watering it well after planting and dividing I don’t think I do anything to it, including cutting it back. It’s sort of semi-evergreen so it never really gets too ugly, but I can’t actually recall ever pruning out any of the previous year’s dead bits. 

And at least in my yard, at the top of its list of attributes is that it is completely untouched by deer and rabbits. There aren’t a lot of plants that these garden destroyers (I’m resisting using and expletive for effect) will not even take a little nibble of, but Geranium macrorrhizum is one of them, likely because of its slightly fuzzy, scented leaves. 

geranium macrorrhizum

I suppose a fussy gardener could ask more of plant, perhaps in the way of large blooms. You won’t get that with big-root geranium. It does have small flowers that fall in the fuschia-purple realm and stick around for a long time, but I’ll admit that I had to double check the color of them. That should say more about me than it does about the plant because they are quite lovely. It’s just that my interest in this plant is far more in the foliage than the flowers (and I’m a flower lover!). And this is as good of a time as any to mention that it gets nice autumn color too.

Am I fawning a bit here? I think I am. But let me put it to you this way. Geranium macrorrhizum is the George Clooney of the plant world: Handsome but not flashy, dependable, able to act in a wide variety of roles and better in quantity. (OK, I feel like I’m stretching on that one but who wouldn’t want a whole bunch of George Clooney’s standing by to help out?)

Geranium macrorrhizum lining a path
Linda grows several hybrids that have Geranium macrorrhizum as a parent together along her shady paths in her garden. Each Little World photo

It is the parent of several hybrids, including Geranium x cantabrigiense ‘Biokovo’, which I also grow, like and recommend. But I feel something more for macrorrhizum. It’s a trusted friend that I never really have to worry about.

So put a little George Clooney in your garden. I can almost guarantee you two will have a long and loving relationship.

Plant to Know: Geranium macrorrhizum



27 Responses

  1. I use this plant to bring order to chaos. Apparently it is allelopathic, putting out some kind of chemical that inhibits the germination of seeds. Perfect! I also use it to shade the roots of young japanese maples and clematis. The complete cover it provides dissuades morning glory! A really fantastic plant, and when something else has grown larger, it is shallow rooted and easy to discontinue.

  2. I was wondering – will it do well in very heavy compacted clay soil – I live north of Atlanta, GA and just got a barren front yard with tall white oaks (so lots of shade in summer) and hardly anything as ground cover. What worries me is the soil – will it like that compacted red clay? I am planning to leave all the leaves from the oaks undisturbed to hopefully make a difference in a few years. We just got the house, and it seems whoever had it had zero interest in their yard, but was diligent with leafblowing.

  3. I had such great success with Hakonechloa All Gold thanks to you, I’d love to try geranium under my douglas fir trees. Which does better in shade? Geranium macrorrhizum or geranium biokovo in your experience? I have a shady spot under Douglas fir trees I would like to underplant. Thanks in advance!

  4. Love, love, love this plant, particularly the fragrance of the foliage when you brush against it. I had it in my Hamilton garden a decade ago but when we moved to Windsor I didn’t bring any with me and haven’t been able to find it since. Will have to mount an all-out search!!

  5. Can I cut this geranium back? I have a small yard in Milwaukee and it’s really taking up too much space. I don’t want to get rid of it; I just want it to be smaller.

    1. I know this is long after your question….but yes, this geranium macrorrhizum can be cut back and it will grow new leaves that are tidier. I often do it one time in the summer if I feel like it. Or, if it gets sunburned and shaggy looking, I cut it back. (Only the one in full sun has that problem.) You can also mow this…so it’s a nice plant to have at a foundation next to a mowing area…..if it gets mowed a bit on the edge, it does not care. Finally, if you have too much, just pull it apart and gift some of it, or put it in an area that needs some sprucing up.

  6. I love this geranium and want it for my new garden. Where did you get yours? It seems to be sold out everywhere and no garden center carries it in my neck o’ the woods.

    1. I ordered it from Bluestone Perennials. The plants were small when they shipped, but they’re 3x the size already (I just put them in last summer).

  7. I feel exactly the same way you do about the big root geranium…I recommend it to people all the time.

  8. Thank you for this post, even though I am viewing it two years later. I have had this geranium plant for 30 years. Moved it, moved it again, divided it and moved it again. However, I couldn’t remember it’s name. Asked several people (I live in Kansas) and no one could come up with it. Figured it was in the geranium family based on leaf and smell. You’ve described it exactly, and now I can label it on my flowerbed map!

  9. I am also a lover of this sweet plant. A sturdy ground cover, lovely pink flowers, and what I truly enjoy most is the lovely scent of the leaves when crushed.

  10. We had a one-acre garden in the middle of a forest in the UK, about 1,000ft above sea level. Both the white and pink varieties flourished, and we loved it. Fantastic ground cover, pretty if not shouting-for-attention blooms throughout the whole summer, needing no attentin other than pulling out the edges when it overflowed a path. What I really like about it is that it’s really easy to pull up so though it spreads beautifully it is not invasive. I’ve come across your page because we’re in a new house now and planting up a cleared garden, and this plant is a must for two borders: pink ground cover under a red-leaved acer, and white ground cover under a silver-leaved Russian olive tree. Glad you like it too! See a photo at

  11. Hands down the best plant for dry shade. I have swathes of it at the feet of sycamore maples, all from 2 original plants; one ‘Bevan’s Variety’ which has magenta flowers, and one ‘Ingwersen’s Variety’ which has pale pink flowers. The leaves smell wonderful and also have good autumn colour. Thanks for featuring one of my favourite plants!

  12. I have a few baby plants of the white flowered variety that I am looking forward to seeing flower. I am going to use them to replace anthing that died this winter. It is nice to have a few areas that one does not have to worry about.

  13. I planted two pint-sized containers of these about 8 years ago not really knowing much about them, but very much needing a ground cover in a “morning sunny” spot and willing to give them a try. I was overwhelmed by how well they did. They reliably popped up and flourished each season, and within 3-4 seasons, they were about 3 feet in diameter, despite the fact that I never water them or provide anything other than mulch. I have since bought several other containers for similar spots–planting four in a bed on the side of my house today, in fact. Obviously I can’t say enough good things about them and was thrilled to see your article on your experience with them.

  14. I have the ‘Album’ strain, white flowers bursting from red buds. It is gorgeous. And the leaves take on red tints in autumn too. It is taking over and it needs dividing, but there are plenty more places it can go!

  15. I lived in Wa state my whole life til now. I’m now in Idaho. In Wa I had lots of these geraniums, and loved them! I started with a pink one. It did spread here and there, which was fine with me. Then, I got some others, don’t know the names, except for Johnson Blue. The others didn’t spread, like you said, unless I divided them.
    I just today, received 9 bare root plants of these from Cottage Farms. I’m so Happy to have them! So exciting!
    Thanks for the very interesting article, sure enjoyed reading about one of my fave things!

  16. Funny you should discuss this plant today – I was just out back looking at how nicely my mine has covered our entire back hill. It is totally ignored up there aside from the continual “cuttings” that I pull to share or move to spots where nothing else will grow. It is a quiet champion in our yard. It really does deserve more respect.

  17. A friend gave me some of this in the fall – I was able to put in in a few spots and it is blooming now. I love it!

  18. I got some of this from my sister in law in Mpls, where it was growing under her coniferous trees. I have a dry slope where grass won’t grow, and I am trying to get this plant to take over. I wish it would do it faster than it is!

    1. One of the great attributes to Geranium macrorrizum is the wonderful fragrance of the leaves; brushing against them is enough to emit that spicy fragrance ( which also repels pesky wabbits and deer ).

  19. I didn’t realize that Biokovo was related to George. I have Biokovo and she is fabulous only she has more dainty leaves and flowers. I have another geranium that I have had so long and moved so many times I don’t know the name. Also a good plant. I can see why you would have a spot in your heart for George Clooney of the garden.

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