Sunday, November 17, 2013

Superior Twinspur: fact sheet!

Diascia integerrima Coral Canyon® at Colorado Springs Water Conservation garden
David Salman once told me that he thought Coral Canyon® was the best plant I ever brought back from the wild. It was chosen as a Plant Select introduction in 2000.  I might think there might be a succulent or two that might vie for that honor, but I have to say that I think this clone has more than lived up to my hopes. Alas--I don't think that many gardeners outside Colorado know this plant yet. This blog is meant to set things straight--

Diascia integerrima Coral Canyon®

This picture shows the upright habit, and delicate coral pink of this taxon. Diascia in general are well known and widely grown among keen gardeners--but most are really miffy annuals that need a great deal of cosseting--except for this one. Coral Canyon® is a landscape plant that loves to grow in full sun, in real soil, and it is a reliable perennial in Denver, given a modicum of good soil and water. Plant any one of the fifty or so Diascia that have been in cultivation in a typical garden bed, and most will poop out before midsummer, and few indeed will come back a second hear. I have had Coral Canyon® plants persist for a decade or more in an optimal spot. And I have seen it (ever so sparingly) growing around the country. The simple, sad fact is that this best of class is still essentially unknown by the great majority of keen gardeners in America: and more is the pity! The first time I grew Diascia integerrima it was the typical wild form, that grows a yard or more tall and flops. I remember Kelly Grummons of Timberline Gardens coming by in the early 1990's to Denver Botanic Gardens, admiring our large clump housed up against the then Alpine House, Kelly remarked "if we only had a compact form of this it would be a winner" (prophetic words, those...)
Diascia integerrima Coral Canyon® at City and County Building
This impressionistic tableau was planted in what had been lawn in  the Denver's City and County building (the mayor's offices) In fact, Mayor Hickenlooper was the one who mandated xeric gardens around Denver in response to the great drought of 1999-2003. We transformed a water-intensive lawn (full of nut sedge incidentally) into a formal parterre filled with drought adapted perennials--a design that became blurred as the long blooming perennials melded into this guache like vision.

Civic Center garden--overview
Same garden...from a bit further away: I love the contrast between the pink Coral Canyon® and the bright Lavender which was used to edge the beds.
Diascia integerrima Coral Canyon® at Civic Center, Closeup
The pink of twinspur lightened up the middle of the garden beds, combining wonderfully with the other tints. Twinspur incidentally refers to the two nectary bearing spurs on the back of the flower that require a specialized insect for pollination--these rarely set seed in cultivation as a consequence. Which is why Coral Canyon® is propagated asexually, and was trademarked as a consequence.
                                                                                                                                                                                                                     Dwarf Race of Diascia integerrima  growing wild on East Cape Drakensberg

A year or so after Kelly expressed a wish that a smaller form of Diascia integerrima existed, I found myself on the wonderful alpine slopes near Naude's Nek, in South Africa. here and there I saw a very small twinspur that resembled the massive clumps I'd seen on Sani Pass, for instance, only less than a foot tall...the picture above and below shows these clumps in the wild--in full bloom. I found a single capsule of seed on these that appeared to be nearly ripe--and from that capsule ultimately derives the plant we now call Coral Canyon®! The cultivar ultimately derives from the wild--so could not be patented. But the name for it could and was trademarked, hence the "registered" symbol following its name: cumbersome. But it designates that this clone is indeed Plant Select's consistent offering. And it has no peer.

Closer view of dwarf Diascia integerrima on the east
Looking at this sparse wildling it's hard to imagine that it can make such a dense mound of color that can persist for months in the garden. Or that this plant would thrive in a variety of soils and climates around the world.
If you haven't yet tried Coral Canyon®, I hope you give it a try! I doubt that given a good soil in sun that it will fail to impress you!



  1. You've knocked my socks off with this one!

  2. In my little "Collector's Corner" of the nursery I worked for in CA, I sold tons of this sweetie. The Corner carried 4" pots so it was enticing for customers to stock up on *more than just one* ... and we helped them with that, of course ;>]] Coral Canyon bloomed its silly head off for an incredibly long season ... a true winner. Really nice to read this backstory!

  3. So glad you knew about this in California, Christi--and that it did well there: how does it do on your magic island? About time we had you barefoot, Mr. McDonough (as if you haven't had me drooling over those dang Epi's of your's...)


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