Wednesday, January 29, 2014

The Potted Life of a Gunnera

As I wandered down the garden the weekend before last I caught glimpse of our Gunnera tinctoria that is sited on the raised bed adjacent to our bottom patio pond. It is dormant at the moment, currently hiding underneath last years growth with its own leaves snapped and folded on to itself to protect the main crown and the smaller bud surrounding it from the worst of the winter. 


On some years we would throw in a few layers of fleece in between the crown and its own leaves just to give it some extra insulation. And sometimes we would even anchor down the folded leaves with netting fastened with tent pegs just in case the winds would uncover it especially as the leaves itself rot down through the course of the winter. This winter we haven't bothered with any of both and just relied on the leaves itself to rest on to the crown and do its thing. So far so good but then again it's been a mild winter so far.

Not a pretty sight but look at those buds!
The main crown and the smaller buds have been steadily increasing in size over the past few weeks and will continue to do so until in spring when they open up and new leaves emerge that will just get bigger and bigger through the course of the growing season. We find that the first batch of leaves that they release tend to become the biggest ones that they'll ever produce in that growing season, with the ones following them only marginally smaller.

Looking at the Gunnera has also reminded me of one of the most common questions we get asked by visitors to the garden: Is it possible to grow a large Gunnera long term in a container?


Yes of course, this one has been container grown by us at least since 2007. I can't remember anymore when exactly did we buy it, perhaps just the year before that but it did live in the garden centre where we bought it from for several years before we actually bought it. As for long term, well that's relative but with the right care a giant Gunnera can thrive in a container for years.

There are two giant Gunneras that are readily available here, G. manicata (Brazilian) and G. tinctoria (Chilean). They both get very big but apparently the former gets a touch bigger than the latter. In reality size difference between the two seems negligible so whichever you choose the care and result you'll get will likely be the same.


This plant prefers a free root run of course and keeping it in a container will curb its growth and the size of the leaves they produce to varying degrees. The bigger the container, the better and leaves they can produce can be bigger too. 

It likes a rich growing medium that is moisture retentive but not permanently waterlogged. Naturally it doesn't grow on ponds or bodies of fresh water that keeps it permanently submerged but rather on the banks wherein it can keep its 'feet' wet by being near the water whilst the rest of the plant well above it. 

So when growing on a container make sure it still has some drainage whilst at the same time conducive to retaining extra moisture which it needs especially in the summer. The Gunnera has an extra high moisture requirement especially in the summer but will also detest being permanently waterlogged. Generous moisture in the summer months will encourage larger leaves and vigorous growth as well as keep their leaves upright even on the warmest parts of the day. Its leaves are prone to droop down when it gets really warm and moisture supply is low and potted specimens are more prone to this, less so for those on the ground.

When we first planted ours on a wooden container it was first lined with strong plastic (compost bags) that were pierced at random places. This made the container hold more moisture but at the same time still has means for drainage of excess of it. Same principle when we transferred it later on to the raised but this time using an old pond liner.

They tolerate dappled shade up to full sun as long as their moisture supply remains constantly high which keeps the leaves from drooping. The best site for it is semi/dappled shade.


How do we maintain ours? In the spring we clear off all the remaining old leaves and give it a dose of liquid fertiliser to give it an initial boost. We also push in on to the soil some plug fertiliser as this plant is a gross feeder and responds really well with extra feeding by putting on large growth. Then it is watered generously as and when needed. As it is on a raised bed with cobble mulch to prevent soil going on to the pond, it has little access to naturally rotting organic matter hence the need to give it summer supplements to support a good display.


So if you don't have the space to have one growing on the ground and getting to gigantic proportions, it is still possible to haveone but grown in a container. It may never get as big but it can still size up enough for an impressive summer show in the garden!

Mark :-)

28 comments:

  1. If I ever lived in a moderate climate with plenty of precipication, the first plant I'd buy is a gunnera. I love everything about it. Unfortunately, our climate here in Northern California is both too hot and too arid to support gunneras. So please post lots of photos of yours throughout the year so I can enjoy it vicariously.

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    1. Will be happy to do so Gerhard :) I hope you guys get some much needed rain soon and get that current drought there broken, cross fingers!

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  2. Beautiful specimen and relatively easy to maintain. What colour inflorescence does your plant produce? I am trying to work out the physical differences between manicata and tinctoria but once I get it I will forget and repeat the process in another few years :-)

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    1. Don, from what I can remember G.manicata has got bigger,fatter inflorescence that looks more 'open' has a colour from green to light pink. G.tinctoria is smaller, more slender and compact and flowers are dark pink to brick red which ours have. I hope that info is right!

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  3. Good to know that these will thrive in pots! They are such huge and interesting plants!

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    1. They are Peter! You have to add one to your garden, no excuses :)

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  4. Mine has been ill treated for years. I think it gets too wet in the winter and not wet enough in the summer. I may buy a new one and start again, using a very large pot with the bottom cut out! I remember when you built the 'prequel' pond!! Have I known you that long???

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    1. We think so Libby :)) well worth trying another one and hopefully it will do well this time!

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  5. Where was that last shot taken? It looks about the size of the one I've been admiring in the display garden at Joy Creek Nursery. I killed one (maybe too much shade) but am ready to try again. My friend who sells them suggested burying a kiddie wading pool in the planting hole. After reading this, I'm guessing a few holes should be punctured in that plastic pool for drainage.

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    1. Ohh I can't remember where exactly that photo was taken Ricki but it is in one of the valley gardens in Cornwall. Well worth trying again and a buried kiddie pool sounds like a great idea, and yes a few puncture holes would be needed.

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  6. I love Gunneras, and yours is beautiful! I have one growing in a hole in the ground that was lined with pierced plastic, but it has been steadily declining, and I'm not sure why or what to do. I may dig it up this year if it's still alive and put it in a container.

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    1. Thanks Alison! A bit of a puzzle there as to why yours has declined, perhaps a few gashes are needed on its plastic lining? I hope it's still alive and might do better in a container. Or perhaps just replace the one on the ground with a new one.

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  7. This is a very good post! I would never dreamed I could grow gunner in a pot. Maybe there is a gunner in my future!

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    1. We definitely could see a gunner in your garden future Debs :)

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  8. Gunneras have an almost mythical quality about them. I've coveted one since I first saw it but it's water requirements make it a difficult plant to grow in southern California, especially when we're so often beset with dry Santa Ana winds.

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    1. They do have that look Kris, helping imbibe either (or both) a mythical or even a jurassic look to its surroundings despite being not that old a plant. They can be tricky to grow in warmer areas indeed.

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  9. That is absolutely gorgeous. The size of the leaves in that last picture made my jaw drop!

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    1. Large specimens are a sight to behold in person Amy, very dramatic and good fun to walk underneath its canopy!

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  10. Like you I was recently out in the garden looking at my Gunnera, folding back the layers of leaves (some of it's own and more from the Tetrapanax next to it). That's when I realized what a fool I'd been! I didn't give it any extra protection during our cold week! It's growing in a large stock tank so also is above ground, increasing it's susceptibility to the chill. Looks like I'll be buying a new Gunnera this spring.

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    1. Don't give up hope on it just yet Loree, it's a tough plant and it could have well sailed through the cold spell with just the leaves as protection. If not, oh well, well worth trying again with another one. Gunnera complements your garden well :)

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  11. Nice idea. I have manicata in the ground but like the idea of one in a pot near the house too. Thanks for the tip! D

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  12. Very nice looking plant. Obviously huge leaves if planted in the ground. Like it's looks but think it is a great one in containers where size would be a little more constricted.
    Cher Sunray Gardens

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    1. It'll get big on the ground indeed Cher provided adequate moisture too. Not as much when in a pot but the growth you can attain from it is still impressive :)

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  13. Very useful information! I'm waiting to see if mine survived the winter. I love the look of your potted Gunnera. Containers are so helpful when there is no space in the ground!

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    1. Indeed Tatyana, and I hope yours have survived the winter, cross fingers!

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  14. I love gunnera, magnificently primitive looking plants. There is a "grove" of them just down the road from su growing alongside a stream with the willows, they are magnificent in summer, and seem to get enough shelted that they just shrug off even the really cold weather we had last year.Never thought about growing one in a pot, I suspect I would get distracted at the crucial moment and let it get parched!

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  15. What a gorgeous plant and I am amazed at how big the leaves get! I'm with Gerhard, please post photos as it grows.

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