PLANT OF THE WEEK #84: Salvia nemorosa types (like 'Caradonna')

There are few plants more striking in the garden, right now (just pre-Christmas in the Southern Hemisphere) than the nemorosa-type salvias.  They’re powerful in shape (piercingly vertical), in floral density (creating a solid block of colour) and in hue (mostly purples, super-heated by red undertones).  In my (and many Aussie’s) current-favourite form, ‘Caradonna’ (though Matt from Antique Perennials reckons I should know better, and that there are far superior forms) even the flower stems are virtually black-purple, which, even lined with flowers are so slender that each stem appears almost thread-like, but dark and wonderfully rich.

These nemorosa-types also happen to be some of the few salvias that will overwinter for those of us in frosty areas.  All the shrubby ones, many of Mexican origin, are killed stone-dead by about frost number six, and have to be replanted in late spring each year.  But nemorosa types are entirely deciduous, overwintering as near-dormant basal rosettes, and can laugh at the worst any winter can dish up (in Australia, at least).  Over about eight to ten weeks from early spring, those basal rosettes shoot up rapidly, carrying smallish, raspy leaves, and terminate in long, emphatically vertical flowerheads that last for several weeks. 

Salvia ‘Caradonna’ on far right, becoming progressively more plum-coloured, as flowers fall, leaving reddish bracts

That is, without doubt, the least complicated, part of their life-cycle.  In human terms, that’s their delightful, trouble-free childhood.  They’re so irresistible over this period that it’s tempting to splash them around everywhere, in great sweeps.  But their troubled puberty is yet to begin.

Without any intervention, following their spectacular early-summer bloom, flowerheads brown off with virtually no Oudolfian charm. The dome of foliage thins to patchiness, and the remaining leaves often carry a bit of powdery mildew.  So to do nothing isn’t an option.  The question is what to do, and hence this post.  I’m hoping, if you’ve had any experience with these undeniably fabulous plants, that you’ll add below what YOU do, to optimise their impact in your garden.

David Glenn, at Lambley Nursery, has long spruiked the method of cutting them right to the ground after flowering, and stated by doing so he could get up to three cycles of flowering each season.  My climate doesn’t provide me with the same response, probably being a few weeks shorter by dint of my elevation and slightly lower temperatures.  Treated in this way, I reckon I’d get one and a half displays per summer.  And in any case, I not a fan of a ground-level gap in my perennial plantings at this time of year, however temporary that might be.  

My management strategy amounts to little more than a thorough dead-head, cutting back to a point where small buds where the leaf meets the stem prove that there’s growth potential.  In doing so, I’m usually able to get a second, rather reduced flowering.  It seems that the potential for regrowth and re-flowering varies enormously from one named form to another, but as far as I know no one has done any comparative studies, nor documented their results.

Salvia nemorosa in its second flowering in a planting by German designer Bettina Jaugstetter

By far the wisest insight I’ve had regarding the use of the nemorosa salvias came from German designer Bettina Jaugstetter, who in planning her large naturalistic perennials plantings, never uses them in large clumps, but dots them through the the whole planting.  In that way, they make an early summer impact spangled about, but are then cut right to the ground, leaving no noticeable gap (being individual plants), and any further flowering is considered a pure bonus. 

There’s a large range of nemorosa-type salvias available in Australia – probably more than we need, to be frank.  I admit I couldn’t see the point in the pink form named ‘Amethyst’ until I saw it used repeatedly, and as the only thing in bloom at that time of year, on a section of the High Line in New York.  The white forms remain firmly in the ‘why bother?’ category for me, but as nearly every other plant prejudice I’ve had has eventually been firmly and fatally challenged, I’m guessing this one will fall as well, in time. 

Salvia nemorosa ‘Amethyst’ on the High Line, New York

We’d so love to hear not only how you may have managed the nemerosa type salvias in your garden, but also which are your favourite varieties, and why!

Discussion

  1. In my old zone 5 perennial gardens I would always plant out ‘Wesuwe’ and East Friesland” in combination with Nepeta and Amsonia tab., or Allium “Summer Beauty”. I found Wesuwe responds to deadheading well, and if cut back by 1/2 after the early summer crescendo will reliably rebloom in autumn. East Friesland responds similarly.

  2. My favourite and go to has been ‘Tanzerin’ it’s a little more blue in it’s undertones and I actually kept the bracts left over after the flowering, I didn’t find them ugly. I agree there’s way too many varieties available which all seem very similar (that is helping me save some pennies though so I don’t have to buy them all and can just propagate the one). And I too though not much of ‘Amethyst’ and then saw it looking fab in someone’s garden! I love the nemorosa Salvias as they are frost tolerant and can survive my garden! They’re also a neat size as I don’t have a huge border and they seem quite polite in the space they command.

  3. Me Again, I had to do some research on this just to make sure I didn’t have horrible taste- re leaving the old bracts on into the winter. In Piet Ouldolf and Henk Gerritsen’s ‘Planting the Natural Garden’ they actually write in regards to ‘Tanzerin’ – “unusual are the prettily coloured flower bracts that remain on the plant long after it has finished flowering”. So maybe I don’t have bad taste! ‘Tanzerin’ certainly did keep a beautiful hue after flowering. Maybe you could try this cultivar? I definitely recommend.

  4. Caradonna is a good variety providing it is in full sun without the slightest bit of shade cast by surrounding plants otherwise it will lean or worse collapse all together. I fins that Tanzarin and Ostfreisland are by far the better nemorosa forms being sturdier and more vibrant in colour and also less prone to mildew. Amethyst is also good, Blue Hills is average at best and Snow hIlls is less so again. And you should forget all the new seed strain lines which are hitting the market as they are far from consistent in form or colour.

Leave a Comment

More Blog Posts

PLANT OF THE WEEK #25: Metapanax delavayi

Metapanax delavayi is one of my favourite members of one of my favourite families, the Araliaceae. As long as one is prepared to overlook common ivy’s (Hedera helix) propensity to be a little weedy ...

All Passion Spent (or lets say 'redirected')

I’m really missing the days of untrammelled plant acquisitiveness.  They were the glory days – that period of time when I lived in one big happy world of new and interesting plants – all of whi ...

The Burst of the Blossom Bubble

I clearly recall, as an eighteen year old in my first year of garden-love, picking up a packet of seed of stocks and reading the info on the back, telling me how many weeks to expect the seedlings to ...