Petasites japonicus – A star or stalker?

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Bloom closeup

Fragrant, yellow-white

Peta-what?  Yes, Petasites.  A very cool plant that you will feel is a star or a stalker in your garden.

I came across this plant by way of  neighboring gardeners, down the road a bit.  I walk by their house a few times a week.  The retired couple living there are always tending to their amazing front gardens.  Every time I see them and their gardens, I get more impressed by their dedication and plantings.

Last year, the woman of the household told me she uses Petasites leaves as an imprint in the birdbaths she makes from a concrete mix.  It is the perfect template because the leaves grow up to 2 to 3 feet in width.  And this is what made me notice the birdbath in the first place on her property.  The sheer size of the leaf is very visible on the bowl of her creations.  So I had asked her, what she was using, and at the time, she didn’t know the name of the plant but promised she would show me its growing habit next spring.

So this year, in April, as I was walking by, the homeowners came out to tell me the plant we discussed last year is now blooming in their backyard woodland area.  They explained the aggressive nature of its spreading habit, via a rhizomatous root system.   As we quickly ventured to see the blooms popping up from the ground, it was apparent how many had reproduced from the original plant.  There must have been 50 to 70 of them in the moist, shady woodland area blooming like little alien pods arising from the ground everywhere.  Fortunately, her husband, the more obsessed gardener of the two, has been serving as the body guard of this plant’s reproduction system by removing clumps every season to keep it in line.  What was once a star in their garden quickly became a stalker.

So we all know, this plant is very aggressive, but not technically invasive, thus I gladly accepted the offer to dig up two clumps to put in my container gardens at home.  Here is the photo I took that morning of the clumps.

Petasites root system

Flower clump first, then foliage arises

You see the yellow to white daisy like flowers that came up first in dense groupings, known as corymbs.  And the rhizome like root structure shoots out a leaf a few inches away.  The flowers are fragrant and kind of odd looking.   I wouldn’t classify them as pretty, but everyone’s taste is different.  And the leaves are not super pretty either, but they become dramatically large within a month or so. After a couple days of transplanting my two clumps into two large pots, the plants started to perk up as the roots took hold.

Now, let’s fast forward to June.  The following photos shows how large the leaves have grown.  And as I mentioned, they can reach up to 32” wide.  Super cool for I love foliage more than flowers – not sure why, guess it’s the way this plant’s leaves bob in the wind, reminding me of the tropics, or these in particular remind me of water lilies.  The leaves are very thin, flat and circular in shape.  If they are kissed by the sun, they will droop down and look floppy or wilted, so I pushed the pots even closer to my house facing a northern exposure and they have been super happy ever since in full shade.

Mid June Photo

Petasites

The area there stays moist and cooler too, so I haven’t had to religiously water the containers; they seem to be happy with a watering every few days.  Also, we have had some rain between our hot days so far this summer.

Leaf Above

Petasites leaf

Upon researching this plant further, it was so appropriate to discover this plant’s Genus name comes from the Greek word petasos.  This means “wide-brimmed hat.”   Of course, I thought – this does look like perfect mold or inspiration for a big showy hat for someone like Princess Kate I would say, fitting as super big flashy hat that only royalty could pull off!  So Kate, do you enjoy gardening?  I say have a hat maker fashion your latest hat statement with Petasites as your inspiration!  Or just grow it in a container as I have done.  Okay, the mind is running away here.  Okay, guess a birdbath will do.

Back to the containers…this plant is a star in my book for containers in the shade or by a water feature.  It grows quickly, is showy, and has no serious disease or insect problems.  But on the downside, it must be kept in check if grown in the ground.  And the leaves are only a plain green, but the veins are slightly pinkish and depending on your point of view, very cool.

On a cultural note, the plant enjoys consistently moist to wet soils in part shade to full shade.  So if you have a full shade location, this plant rocks!  The container can be sunken in mud even, if you want to have a water garden effect.  As I said, the circular shape of the leaves remind me of a water lily.

Early June Photo

June photo

Petasites japonicus is known as butterbur – because, as I read further, the leaves were apparently once used to wrap butter in hot weather. (Hmm, interesting, I thought.)  This plant is also referred to as fuki or sweet coltsfoot.  The petioles (stalk of the leaves) are eaten as a vegetable called fuki in Japan.  In fact, its native range is Korea, China, and Japan where it is found growing on wet stream banks in wooded areas.  The stalks grow long and support the leaves above.  I think the stalks look a bit like rhubarb stalks or stems.  Maybe they are in the same family.  This would require more research.

In summary, this plant serves as a vegetable, water garden plant candidate, will naturalize (so beware of this and keep it only where you can control it, like containers!), and has strange alien-like fragrant flowers in spring, and is easy to grow to huge proportions for a large, very showy, extravagant foliage display – fit for a queen …or princess!  It is hardy to zones 5 to 9 and is an herbaceous perennial.  Eventually the whole plant will reach about 3 feet tall by 5 feet wide.

If you think you would like a few, give me a call.  I know where to get them!  Cathy T

Fall Update to This Post:

October is here and I’ve begun the process of overwintering many tropical like plants from my container gardens.  This being my first experience with growing Petasites japonicus (Zones 5-9) in large containers, I started searching on the web to see if I could find any sources on how to overwinter them  in CT.  Granted, they can survive our zone and are very hardy, but they are too aggressive to grow  in the ground, thus a test in containers evolved this year.  I hope to have them return next season.

The leaves by now started to have lots of holes in them due to a slug or some other nuisance insect feasting on them recently.  Almost all the wide leaves had scattered holes in them.  As I began to cut away most of the foliage and stalks, I noticed a bulb like structure at the base of the plants, all plump and full.  “Interesting,” I thought.  “Another new feature to be curious about on this unusual and large showy foliage plant.”

Fall Photo of Base

My plan is to cover the crown of the bulb-like structures with mulch to provide some insulation, and maybe even a big blanket over the top or around the containers themselves.  Then hope for the best.  That bit of insulation will hopefully recreate the insulation of fall leaves in a forest.  And so long as the mice in my shed don’t try to eat any remnants, all should go according to plan. However, if you find or know of anyone who has tried overwintering these plants in containers in our area, please let me know.  I’d love to hear of their experience to ensure success of my trial.  Cathy T

26 thoughts on “Petasites japonicus – A star or stalker?

  1. I just bought a Pestasites Japonica varigata and will heed your advise about the invasiveness of this plant and plant it in a container! Please let me know how it overwintered : )

    • Hi Marti – Couple things – You should use a big container because it grows quite large, and likes LOTS of water. I water mine often and a lot in my containers, and it is a shade lover to part-shade. Also, although it will stay contained in the container, when it flowers – watch out so that seeds don’t go into your garden bed which can happen, and once this plant gets a foothold – it can be a real problem spreader – so use caution and be aware. You can cut the flowers off before that happens, for I enjoy the foliage more. I put my pot in the shed here in CT, and it has come back for the last four years. Basically I do nothing but roll it in there at end of fall, and take it out in May and it will already be popping out of the soil. I love this plant for the huge round showy foliage. A lot of problem plants in the garden are stars in containers – a book I should write, I speak about this in my talks! Thanks for asking. Cathy Testa

  2. What size pot are you growing this in? We have a boggy area but I don’t want to annoy the neighbors and have something like this spread into their yard. I’d love to do it in a container and lots of local stores are carrying HUGE containers lately. But what if we get one so big we can’t overwinter in our shed? Do you think it would be ok outside in zone 5 if we cover it with a bit of mulch and burlap? Or should we struggle to get it in the shed? Also how large does it get in a container? Can they get anywhere near as tall as when they’re in the ground? We have a north facing deck that these would look great on!

    • Hi Kris – A big pot is the way to go, you could leave it outside in the pot if you want because it will survive in zone 5 with a bit of mulch as you noted, or burlap – but important to note – when the plant pushes out blooms, cut them off before any chance of seeds because it will self-sow in the bed where you put the pot or nearby – and you don’t want that, they are tough to remove and will spread. It would look amazing on a north facing deck, they like lots of water so you will have to water them regularly. If you can get a big pot that can stay outdoors in the winter, that would work. I will measure the pot I have had mine in and write another comment but I think it’s at least a 22″ diameter about 24″ deep. Cathy T

  3. I’m very interested in this plant petasites japonicus….could you send me info how I could acquire one. Thanks so much I’m in Birmingham Ala and can’t find this anywhere!

  4. Pingback: Search Terms – A Look at Last Week’s | Container Crazy Cathy T

    • If you are local to my area in Connecticut, you may inquire at The Garden Barn in Vernon, CT. I remember they had some at one time, but I don’t think it is commonly carried by nurseries. You may want to ask Logee’s or perhaps Woodland Gardens as well. If you go – tell them I sent you! I don’t have any myself at this time, but my neighbor has a whole backyard of them – I should go visit him this spring to see if he can offer some up again! Cathy Tl.

    • Robert, where are you located? In CT? Try Garden Barn in Vernon, CT. I do not currently have any of my own in stock at this time, but hope to try to get some more later maybe!

  5. Hello,
    I am in the process of removing the Petasites japonicus giganteus from its location in my yard because of my concern for its invasive nature. Of course I’ve known about that, but the humungous leaves are so great that I’ve just been trying to keep a DMZ around it. I’ve enjoyed its crazy-big leaves! But it’s moved into my neighbor’s yard and, well, it’s time to go. I’ve filled three large trash barrels with the finger-thick runners (near the surface) and pencil-thick rhizomes (down 15+”), and still have as much again to go. I pay the landfill to let me take it there. (The leaves and stalks went into other barrels in addition, and can go in my compost pile). I have to dig down 15″ to get the rhizomes, and am sifting the soil, but am sure there will be some left to sprout! It’s been a HUGE amount of work and I’m only half done.
    I live in midcoast Maine, zone 5 and sometimes 4. It overwinters outside under the willow tree just fine. If it gets dry, the leaves sag, but other than that it’s quite happy here all winter with no special care or mulching.
    I have just scored a few 5 gallon plastic planter pots and now will try to put some of the plants in those and into the soil, hoping to contain the spread but still grow it, and see if that works.
    I think that the ideal location, in terms of control, would be the center of a paved cul-de-sac!!
    DO NOT, I repeat, DO NOT put this ANYWHERE where you cannot control the spread. DO NOT put it in a bog or wetland or near a waterway! This should only be planted in the ground where the owner is conscious about its spreading nature and COMMITTED to taking it out if it gets out of control OR before the owner moves away! anita@scottsnet.com

    • EXACTLY my point and I agree wholeheartedly – do not plant this if you can not become a crazed digger working tirelessly to remove it and as noted on my blog, with my warnings, I would only put in large pots and make sure the roots do not escape the pot below into soil where it will remake it’s nature to take over the ground. I put mine in pots on my deck and then store the pot in an old shed over the winter. By the way, thank you so much for sharing your input. One day a lady stopped here and showed me her “finds” at a garden sale – I said, that is Petasites, don’t plant that in the ground, it spreads. She looked at me in surprise. I said, just remember, I’m giving you a warning about this so you really understand. Put it in a pot! Cathy T.

  6. Why do you need to overwinter it moving your pots? Will tubers die if left outside during winter? Since you said it’s and aggressive spreader I would expect to leave the pot outside all year.
    I just ordered one plant that I’m planning to grow on my balcony in bright indirect light.
    I can give it protection from winter rain but not from cold, even frost sometimes. I live in the North of Italy, Near milan. USDA 8a

    • Our zone is too cold for it to survive in a pot outdoors in MOST cases, but yes, it is so aggressive, it may survive the freeze cycles of a pot but I always just put mine in the shed and it survived there – protected but still cold. GOOD Point!

    • I move some of my containers inside to protect the pot, not the plant itself if it is aggressive. For super large pots, I cover them with boards and plastic tarps to protect the pots from too much winter exposure – and the pots have not cracked thankfully! That is why – Italy – WOW!

  7. Hi, I am slowly getting crazy with tropical plants in ground and containers.
    As far as butter ur goes, is it too late to plant it now? I’m close to Seattle, have a source where I can get plants. Often I’m too eager to mother plants when waiting is needed.

  8. Hello, could you tell us what type of pot you used for your Petasites plant? I found some plants for sale at the Tripple Brook Farm website. Thanks!

    • Hi Mary, I use a big plastic outdoor pot that is about 22″ in diameter and about as deep or a bit more. I tend to like “big pots” so that is my style. Remember, it will try to grow roots out of the bottom to escape and spread so a bottom tray is helpful to place under the pot, and it is essential all pots have drain holes for appropriate drainage in container gardens.

  9. Thank you for your help! I can’t wait to grow this, but I do want to keep it from invading my garden. I bought one of the regular species and one of the ‘Giganteus’.

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