Thursday, July 07, 2011

The Allure of The Kalopanax

Kalopanax septemlobus, the Prickly Castor Oil tree, and a sole species in its genus is one of my favourite plants, so much so that we have several in the garden. Even now, whenever I spot some in the nurseries we visit I still find myself gravitating towards them, admiring the overall form of the plant with it's lush leaves on spiny stems, gorgeous! Mind you, I say that about a lot of plants and I have loads of other favourites too, but there is something special about the inherently unique Kalopanax.

Lush leaves....

...with prickly stems, irresistible combination!

This plant is deciduous in the winter and is apparently hardy down to minus double digits in celsius, thriving in parts of continental Northern Europe. Certainly at least it's been hardy enough in our garden. It can grow into a huge tree but is easy enough to keep juvenile by regular pollarding and pruning in the spring to keep it into a more manageable size, and as an added bonus can respond to the treatment by producing even bigger leaves in the summer. Virtually pest and disease free, it has very little special requirements apart from occasional supplemental feeding in the growing season, as well as being watered on dry spells. I do suggest though that it only gets pollarded every so often, letting a year or two pass by in between them, as well as siting on a well drained site that doesn't get waterlogged but doesn't dry out either. It prefers a full sun to a partial shade aspect.

There are several leaf forms available of essentially the same plant, at least three that I know of and possibly even more,  including ones that are 'in between' these leaf shapes. There is no reliable or standardised naming for these various leaf forms which makes sourcing rather tricky, especially if you're after a particular form.

As a fan of this plant I regard all of the leaf forms of Kalopanax as beautiful in their own right and worthy additions to the garden, but for some one leaf form would be more desirable over the others and would only go for that one. Makes sense too especially if space is limited. Some nurseries sell plants that have different variety names attached to it, while others carry on using variety names that have been used before (like the name var. maximowickzii). This is a grey area and I'm aware that at one point all of the variety names used before were deemed not valid for use, and that whatever the shape or form of the leaf this, they are all just Kalopanax septemlobus. I'm not updated if things have changed and if the older names can be officially used again (as well as new ones) but I would highly suggest that this is one of those plants that are best bought in person. You purchase if you like what you see in front of you rather than rely on whatever variety name it has.

As I've mentioned earlier I'm aware of at least three leaf forms of this plant and we have them in the garden. As a rough guide here they are using my unofficial names for them, based mainly on the general shape of the leaf and what I associate them with. The names may be unofficial but it will give you an idea on what to look for (and what's available) especially if you decide to source for one (or more!). Another thing worth noting is that juvenile leaves do vary in appearance compared to the more mature ones on the same plant, but the difference in leaf shape amongst the other forms (juvenile and mature) are still very discernible from each. Whatever leaf form they may, they are all very prickly so caress the stems with care.... or caution.

The 'Acer' leaf form
The leaves of this form remind me of Acer palmatum or Liquidambar leaves, palmate in appearance but not as deeply lobed. When in full leaf it can be easily confused as a Japanese Acer but much faster growing, and a glimpse of the spines will quickly indicate that it is definitely not. I think it's equally at home to lush planting schemes, minimal Japanese style gardens, or gardens with a general oriental theme.

Juvenile leaves
Mature leaves at the top of the plant (not to be confused with the Fatsia japonica leaves beneath)

The 'Fatsia' leaf form
The leaves of this form remind me of nothing else but the leaves of good old Fatsia japonica, with its palmate shape that are much more lobed than the previous leaf form. And the leaves are much bigger too, probably the biggest of all the forms. Also of all of them it has the most traditional 'Castor Oil' plant in appearance.

Juvenile leaf
Mature leaf
Mature leaves at the top of the plant

The 'Duckfoot' leaf form
Ok, I can't really think of many plants are called duckfoot (apart from one variety of Hedera) but with it's distinctively well dissected leaves and shape, they remind me of the webbed feet of ducks. And funny enough this unofficial name is more widely used than I thought (as an easy adjective when making enquiries on nurseries). This seems to be the most desirable of all the leaf forms, with availability constantly low hence can be tricky to find. 

Juvenile leaves
older but still juvenile leaves
Mature leaves, note that the leaves are no longer as dissected as the juvenile ones but the form and habit is still distinctive from the 'Fatsia' form
This form is supposed to be the one referred to as var. maximowickzii but the validity of this name is still hanging on a balance, although some nurseries still persist in using it. Just be careful when buying online of plants still labelled as this, you may not get a form that looks like these photos but rather get something more similar to the other ones.

A newer specimen, only planted out last year but I consider it under this same leaf form...
or could it turn out to be another variation, a fourth leaf form?? Time will tell!

Because of the confusion with the naming, it's best to buy this plant in person, so you can actually pick up the leaf form you wish to acquire. If doing so by mail order, it's worth asking for a photo of the actual plant they will sending (or stock), so you know what will be coming. If you're not that fussed, then consider it a lucky dip! After all, I think they are all lovely :-)



  1. Lordy...I've never heard of or seen this plant!!! You guys seem to get all the good ones years before us!

  2. Learnt a new word today - pollarding !

  3. It looks like a dangerous plant, those thorns are hard. We have castor oil plants growing in the marginal areas but looking like invasives. Maybe it they will be planted in pots they are lovely too, without those thorns.

  4. Loree, I'm surprised it's not yet readily available there. Although I bet there's a few going around. The long heritage of British plant collecting has probably paved the way for a more relaxed attitude towards introducing new plants here. There have been mistakes of course (Japanese Knotweed, etc.) but it hasn't dampened the system, and it never fails to amaze me what's actually available here. If only it's that easy to do some plant shopping here and bring it across the atlantic.

    b-a-g, I still learn new things all the time.

    Andrea, tropical castor oil plants are the most stunning of the lot :)

  5. Oooh those thorns look painful. But the leaves are truly majestic, I can see why you like them. Great post, I've learnt a lot.

  6. You continually amaze me with plants which I am unfamiliar with. The Kalopanax did bring Fatsia to mind but those thorns do indeed look lethal.

  7. I have been growing Kalopanax septemlobus, for about 10 years now and love the foliage and of course the sharp prickles! You have some fabulous forms that I have never heard of – it would good to know where you get these wondrous plants from?

  8. I grew this once in my garden's infancy (read horrible soil) It barely survived the summer. I did not realize it had spiny stems. How did I miss that?
    Thanks for the info and the reason to go look up "pollard"

  9. Mark you are wealth of knowledge. Thank you. What an interesting tree. Thank goodness for google too. We have a plant here called the castor oil plant which is a declared weed. It has similar shaped leaves but isn't spiny. I was a bit confused so looked it up and it's Ricinus communis - not to be confused with your plant Kalopanax septemlobus which, as you said, is the prickly castor oil tree.

  10. Another stunning plant that I'm not familiar with. How many more do you have in your garden??? :-)

    I love being inspired, and this post is another reminder why I love your blog.

  11. This one is new to me, Very nice post! I have two castor bean plants (a red & a white) and I adore this style of shrubbery. This plant looks interesting indeed, it's thorns are intense. I'll keep my eyes pealed I guess.

  12. Thanks Martin, Alistair, the foliage is lovely and is a worthy addition to your gardens :) Just be extra careful with the prickles!

    Cheers Will! I originally got some of them from Burncoose and they do stock all three forms. Other nurseries that stock the various forms are CGF, Beeches, Duchy of Cornwall, Cross Common, Crug Farm, and Panglobal Plants.

    Nellie, I'd go on to say that a good drainage is crucial in succesfully growing this plant. I lost one before which was sited in a 'too moisture retentive soil' (clay). Give one another go :)

  13. Thanks Missy! There's still lots of new things to learn everyday, I definitely still do. I find it easier to learn about the plants I like, I don't always bother with others I'm not that fussed about. Ricinus communis is treated as a lovely annual here, can grow to a huge size in just one growing season :)

    Just a few more Gerhard :) Thanks for the lovely compliment! You must try and track down one, it'll look great in your garden!

    Hi Nat, glad you like it :) Be great if you can get hold of one, careful with the prickles though!

  14. I am unfamiliar with these plants, but I can see why you like them. I think I like the fatsia form best! I love the internet; there is so much out there in the great, wide world!

    P.S. The 'Adam' fig you featured in your prior post is amazing. I'm afraid Adam could never have covered up with the leaves growing on the little fig tree I planted this spring.

  15. I would love to find one of these for sale here in Florida, assuming it could tolerate the heat, humidity and warm nights! I like the spiny stems as much as I do the leaves. :)

  16. Hi Debs, I think between the leaf forms it's neck on neck between the 'Fatsia' and the 'Duckfoot' which is my favourite. I just like them all :) If you can get hold of an 'Adam' fig it would be a lovely addition to your garden :)

    Steve, I think they can tolerate summer heat and humidity as they also thrive in continental Europe. Hopefully you can source one soon, cross fingers! :)

  17. How amazing to have those wicked thorns with the the huge lush leaves. I can't make my mind up which leaf form I prefer - all of the above?! I didn't realise how hardy these are, I'll have to remember them if I ever need to plant up a largish partially shady space.

  18. All of the above would be great Janet :) it will be a great addition to your garden if you decide to plant one.

  19. Loree, we need to poke some of our local plant acquirers with a sharp stick until we can get one of these. It's a crime that the danger garden doesn't have one.

  20. Ryan, you and Loree should start poking very soon, and be persistent too! :) I'm still surprised it's not readily available there as it's been doing the rounds in nurseries here for years now.

  21. I love the 'Duckfoot' form and will have to hunt one out for next spring.

  22. Ha, you guys just answered the one question for me that I couldn't find an answer to about this plant. I just got a seedling of this and was hoping to pollard it to keep the juvenile idea of I could but if you guys say so, it must be possible!

    1. Yes you can pollard this plant and you'll get even bigger leaves as a result :)


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