PLANT OF THE WEEK #75: Echium 'Heronswood Blue'

For years – I mean decades – I’ve been trying to establish the difference between Echium fastuosum and Echium candicans.  And now it appears that the names are synonymous. Yes, that makes it much simpler, and I’m mighty glad for that.  But it also makes me grumpy that I’ve spent years trying to see the differences that so many lame references claimed to exist.  I thought I was the problem, when it was them all along. 

Echium ‘Heronswood Blue’ is a very fine, brilliantly electric-blue colour selection of this striking shrub.  Or maybe it would be more accurate to say ‘of mostly this shrub’, as there may be traces of other species in there.  Echiums are notoriously promiscuous, and no one can really quite vouch for the purity of pedigree of this, or almost any echium grown here in Australia.  Indeed, it’s this promiscuity, and also variability, that makes buying an Echium, other than one specifically named, and vegetatively propagated (and therefore a clone of its parent) such a lucky dip. They’re all worthwhile, but some are much better than others.

When your sources aren’t entirely reliable – all three plants here bought as ‘Heronswood Blue’, but only one appears to be the true clone. As you can see, all are worthwhile, but the more brilliant blue entirely eclipses the others nearby

There’s a lot to love about Echium candicans, and specifically ‘Heronswood Blue’.  It’s fast – I mean CRAZY fast – in growth, it loves poor soils, it revels in heat and dry, and in full bloom is as showy as it’s possible for any flowering shrub to be.  Of course all those remarkable qualities are going to be offset by some irritating characteristics as well (as they nearly always are in people), and Echium candicans can be very short-lived, and has a habit of collapsing rapidly and dramatically, due to what appears to be fungal attack.

Echiums candicans insists on perfect drainage.  It’s a non-negotiable.  And it’s extremely susceptible to frost, which is hardly surprising, given that it comes from the island of Madeira.  Like so many shrubs from hot, dry parts of the world, it will respond very well, initially, to the well-fed soils of gardens, but its consequent rapidity of growth will almost certainly be at the expense of its longevity.  Such plants last longest, both in actual life-span as well as in their effective contribution to the garden (not the same thing!), in low-nutrient soils that curtail their growth rate.  In most garden settings, it’s worth considering that you’ll be replacing Echium candicans on a three-to-five year basis.  It’s well worth it.

The plants themselves, even when not in bloom, can be quite striking when young and vigorous, forming a tight dome of silvery rosettes.  The density of the dome tends to thin as old flowers are deadheaded, and it some point you’re forced to consider whether your plant is past its use-by-date.

Unfortunately, Echium ‘Heronswood Blue’ doesn’t come true from seed, so summer cuttings are probably your best succession plan, or a return trip to the nursery.

Deviating for a bit away from ‘Heronswood Blue’, by far the most striking and seriously elephantine forms of echium I’ve known appear to have been hybrids between the shrubby E. candicans and the monocarpic (once flowering, followed by death), single rosetted E. pininana. They’re roughly shrubby, though not as branched as straight E. candicans, and their flowers, snaking to the ground, then rise and arch overhead, to about 2m.  E. pininana itself grows straight up, in a single tower, to up to 3m.  The best planting – by far – I’ve ever seen of this was at Winterhome garden in NZ, in which a long narrow avenue of tightly trussed Italian cypress were backed by a solid forest of equally narrow, and upright echiums. 

Echium wildprettii at Longwood, USA

Then, of course, in total breach of the single-plant-focus that this blog is supposed to follow, there’s the pinky-red Echium wildprettii.  It’s such a collectors plant here that you only ever see it in Australia as a single specimen.  A repeat planting of them, as I saw about a decade ago in the glasshouses at Longwood, in the USA, looks like something dreamt up by James Cameron for Avatar.

We’re going to visit Winterhome in April, on our amazing eight-day NZ tour.  Why not come with us?  Check our the details at


  1. I’m so glad you have mentioned this doesn’t last all that long. I get so frustrated with some plants and this is one of them. It was made for my garden in Clunes, I just knew it, or I should say the light in Clunes, for some reason a certain pink, grey blue leaves and a blue all seem to come alive in what can be a dry, harsh landscape. Of course mine died in the first frost, and since then completing a small section of the acre with well equipped plants gives me far more satisfaction than in my echium smug days. It’s the journey, at least I hope it is, as I’m not sure if I’ll ever see the finish, and certainly not with echiums. Send them my love.

  2. We have a large rural garden at Scotsburn near Ballarat on red volcanic soil, with masses of echium. I was surprised by Michael’s comment that they are very susceptible to frost. We get regular frosts and have not found this to be a problem. Self seeding was not mentioned, which can be an issue. At least that solves the problem of replacement when they do get woody and leggy after a while. But means lots of dead-heading in some areas. The honeyeaters love them. Great mixed with Euphorbia wulfenii. This year ours seem somewhat confused and have been in full flower since July and still going strong.

    1. I guess there’s frosts, and there’s frosts. Our frosts are such that we can’t with any confidence or regularity flower wisteria.
      And I appreciate your comment about self-seeding. I’ve never gardened in a place where that’s a problem, but it clearly is for Jenni in the Wimmera (comment below or above) as well.
      Another commenter on another platform made the point that they don’t like being transplanted. Funny, but you can kind of tell that at a glance, can’t you? It’s like so many of those very fast growing, dry loving shrubs/subshrubs. They’ll only move when very young.

  3. Thanks Michael for this discussion on Echium. I’ve long wanted to take the plunge and plant this beauty of the garden but have seen too many examples that I now know, were past their use by date. Now that I know this I’ll give them a go and replace them, as you suggest when necessary.

  4. Love the form of these shrubs equally. Judicious removal of low branches that rarely produce a flower spike and thinning of small side branches below the rosette-shaped growing points make these shrubs quite architectural and gnarly features in the garden.
    Very promiscuous plants courtesy of bees and throw-backs, I wish I never dropped a soft pink one into the mix years ago.
    Dead-heading prior to seed-ejection day is critical in our garden – unnoticed volunteers have been found pushing bricks apart!

    1. How long do you find they last for you, Jenni, with all of that TLC?

    2. This prompted a scrounge through photos to check how long Echiums last in our Wimmera garden.

      There are at least 3, really in their twilight years, that I can vouch are still living after 11 years. It’s most likely they are much older as the 2010 pic shows very established shrubs, possibly 3 or so years old.

      These particular shrubs receive the toughest of love; poor heavier soil, little irrigation but good drainage courtesy a sandy base… but judicious pruning. Generally, I would normally get 6-8 years if not too pampered.

      Conversely, in town 10km away where the soil is heavy and black, these plants go bonkers and grow themselves into a palliative state within 3-5 years.

  5. I was so surprised to read your comment that candicans and fastuosum are synonymous. I was propagating Echiums of both species from stock plants with distinct differences, particularly in leaf shape for a number of years at S&G.

    1. Hi Diana, that’s so interesting. I recall that both were listed on the S&G list – I’d love to know how the ID was established, or verified. Several influential sources (inc. the RHS site) list them as synonymous. Honestly, I don’t think anyone really knows what we have, or how pure the bloodlines are

  6. Love echium flowers and foliage even more. Used to have it in my garden but we are really too wet and it has succumbed to a wet winter .

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