National Tree Week 2019 – Day 7/8: The dichotomy of the Prickly Castor Oil Tree


So here is an exotic, tropical-looking tree (height ~25m), often grown to give a jungly feel to a garden, that can rather surprisingly take temperatures of down to -40 deg C. Yes, it’s seriously that hardy. It’s name is Kalopanax septemlobus, otherwise known as the Prickly Castor Oil tree or Tree Aralia. It hails from Asia.


I don’t have one in the garden since it punches out large prickles along the surface of every appendage (e.g. see photo below) and I avoid thorns where possible.


This one is growing in the gardens at Wimpole Hall and once again I must confess to not really seeing the tree, for years. In fairness, this is largely because it has always looked like a simple, vicious stick with a few palmate leaves on the end. On some trees the leaves can be deeply incised and very ornamental, on others not so much. Its autumn colour is usually good too.

This summer something wonderful happened. It flowered …


and was completely covered in huge clusters of ivy-like flowers, which were completely covered in insect pollinators.

And now the tree is laden with black sticky seed heads that are proving irresistible to the birds. Last time I passed the tree there were lots of blue tits performing aerial acrobatics to get at the fruits. If you look carefully at the silhouette photo above, you can see a tit in the middle of the photo carrying off a seed, but here is another slightly better shot of one making off with a seed:


So if you can put up with those prickles, this is a useful ‘tropical’, but hardy tree with interesting features and good wildlife potential.



About Frogend_dweller

Living in the damp middle of nowhere
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4 Responses to National Tree Week 2019 – Day 7/8: The dichotomy of the Prickly Castor Oil Tree

  1. Tina says:

    I can see the bird, berry in beak, clearly–great capture. In the photo just before that one, the seed heads look like a group of exploding firecrackers, with out the BOOM and with a blue sky accompaniment.

  2. Chloris says:

    This is new to me. It might be prickly but it looks very dramatic. Great shot of the bird after the seeds.

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