Groundcover Banksias

So how about a post about plants? Fancy that. Long overdue, I know.

Our Banksia repens specimen on display at the WSNLA garden at the Northwest Flower and Garden Show seems to have generated quite a bit of attention, as people are still talking about it, as in: what a weird plant! I’ve never seen one before. I didn’t know it could grow here. You can’t grow that here. Where did they get it? Well I can answer the last question: I grew it from a seed in 2005, which came from Nindethana Seed Service.

As for the other questions, well, here’s what I know: certainly not everything. There are six species of groundcover Banksia that spread in this rather bizarre fashion of completely prostrate and sometimes underground stem growth, big leathery leaves sticking up from the ground, and flowers that also appear to arise from the ground itself, sometimes out ahead of the foliage. These are B. repens, B. blechnifolia (the foliage of which really does resemble a Blechnum fern), B. gardneri, B. goodii, B. chamaephyton, and B. petiolaris. All of these are native to Western Australia, which has a similar climate to ours in that summers are dry and winters are relatively wet, but it is somewhat warmer year-round. Nevertheless some of them seem to have impressive (considering their Western Australian origin) frost tolerance. B. blechnifolia has survived unharmed down to the upper teens in a Grants Pass, Oregon Garden, where summer temperatures are probably very close to what it is accustomed to in the wild. In this same garden, B. repens survived 12°F in the December 2009 freeze with only a bucket over it for protection, which I consider to be quite impressive. This species is generally regarded as less hardy than B. blechnifolia in Australia, but who knows?

And that is about all we know, as the other species have not been tried in the Northwest that I know of. In other words, quite a bit of experimentation remains to be done with them to find out just what they can tolerate. I’m not really planning on any of them to be hardy enough for general use by normal people; rather, they’re fun subjects for the adventurous gardener with the perfect sheltered corner and excellent drainage. They have a reputation for not handling wet summers too well, so it’s “no summer water, please” once established. Imagine one creeping along a raised gravel bed at the corner of a driveway… or on the west side of a house with a stone foundation… hmm…

A few other groundcover Banksias that might be considered more “conventional” in habit (i.e. branches above ground) are also known. These tend to be forms of species that generally grow upright, but are also known as prostrate or low-growing plants in a few restricted parts of their range in the wild: B. media, B. spinulosa, B. integrifolia, B. serrata, and probably a few others. I’d be surprised if there’s not a groundcover form of B. marginata out there somewhere, and I’d sure like to grow it as B. marginata is one of the hardiest species, and it is certain to be a good garden plant. (B. marginata ‘Mini Marg’ is a nice low, spreading form but as it appears to grow 2′ tall doesn’t quite qualify as a “groundcover.”) There’s a photo on the web of a nearly prostrate B. canei ‘Celia Rosser’ with commentary that it may be extinct in cultivation. If that’s true, well, what a pity.

We hope to make B. blechnifolia, B. repens, and perhaps B. gardneri available for sale over the next year or two. Stay tuned! We also have managed to procure the prostrate form of B. serrata, which is rather exciting; but I’m not sure when I’ll manage to produce any for sale.

A quick reminder: don’t forget to visit us at the Bloedel Premier Plant Sale coming up April 16 – 17. If we have been talking it up quite a bit, well so have they – in fact, they told us to “bring a lot of plants” (like we weren’t going to do that anyways?) since they are expecting a huge turnout. I guess we’ll find out! In any case, it sounds like it ought to be exciting.

Here’s a quick sampling of information about groundcover Banksias on the web. There’s lots more out there if you search. Enjoy.
Banksia repens
Banksia blechnifolia
Banksia gardneri
Banksia petiolaris
Banksia goodii
Banksia marginata ‘Mini Marg’
Banksia canei ‘Celia Rosser’


Banksia repens at UCSC Arboretum, Santa Cruz, California.

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2 Comments (+add yours?)

  1. Ryan Miller
    Apr 15, 2011 @ 10:24:33

    Very cool! I just found you via Facebook (via Paul Bonine’s facebook page). I knew about you guys before, but didn’t know you have a blog. I love groundcovers and I live Proteaceae that I can grow outside in the PNW. I’m wondering if you were the source for the Grevillea x gaudichaudi that I just got from Cistus?

    I really love the leaves and stems on that Banksia repens.

    Reply

  2. Ian
    Apr 18, 2011 @ 12:54:21

    Actually, I think they had it long before I did. In fact I think I may have gotten my second one from them after my first one croaked. Glad you enjoyed the blog. I’ll be trying a number of the hardier South African Proteaceae in the future, so stay tuned!

    Reply

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