Location, location, location...(some thoughts on zone denial etc.)

Alpine House, Kew in 2010

Kew is generally acknowledged as the greatest botanic garden on Planet Earth: its glorious history, unbelievable herbarium and vast grounds full of treasures will ensure that in perpetuity. I have always thought that the Alpine House at Kew (here shown in its current sleek manifestation) represents the institution's unique and vital plant collections, however, and others (not as rock gardeny as me) have agreed. It would take several thousand blogs to properly treat this treasure trove, but I'd like to examine a few plants here and their location (comparing these to Denver), which I think will help illuminate a few perplexing issues: plant hardiness, invasiveness and zonal denial chief among these...

Inside the alpine house

An overview of one of the many mini-gardens that fill the structure--each and every plant has a story to tell (most of these plants are grown in pots and swapped in and out at their peak show periods--maintaining a breathtaking show through the entire gardening year)...



Salvia daghestanica in the Kew Alpine House

One of the first plants I noticed on entering the Kew alpine house was this lovely specimen of a lovely Salvia first collected by Henrik Zetterlund in southern Russia which has become a beloved Plant Select star performer in Denver. Friends throughout Europe have told me that this wonderful salvia is essentially impossible to grow in a garden: below you can see how it performs in typical xeriscape conditions in Denver: location, location, location!

Salvia daghestanica in Denver

It produces a few more blossoms in our intensely sunny steppe climate as well you notice!



Puya cf. caerulea outside the alpine house
Look below



Closeup of the Puya blossom

 
 Before you start to feel as though Denver is more congenial for growing things than England, consider the puyas: Kew boasts several vast mounds of puyas growing unprotected at the fringes of their rock garden--this would almost certainly perish with the first hard frosts we experience in Denver (Kew is Zone 8--some years barely experiencing frost at all)...location, location, location.l

Boy, would I love to grow this Puya outdoors here: I guess we'll have to settle for agaves and yuccas (although I did see puyas growing very high indeed in the Andes once...)



Scarlet bugler penstemons (left) and Apache plume (far right)

I was amazed to see large masses of our native Penstemon barbatus (which usually grows in relatively dry parts of the American West) thriving in open beds at Kew--and not far from these a very handsome large specimen of Apache Plume (the white mound on the right of the picture): Fallugia paradoxa is even more xeric in its distribution: both of these seem to find Kew's location to be just fine, thank you. Go figure!



Myrtle spurge Euphobia myrsinites

One of the most surprising "treasures" I saw at Kew was this ancient, gnarly, bonsai-like spurge--a plant which is classed as a noxious weed in Colorado! I have seen this Euphorbia lovingly displayed at many European botanic gardens. Euphorbias present some fascinating issues I have discussed elsewhere...how can a plant that is pestiferous in Denver be a treasured alpine house denizen in England? Location, location, location!

I am coining the term "charismatic nega-flora" for plants like this which have inspired a veritable witch-hunt like zeal while the much nastier (but less attractive) Euphorbia esula causes far more trouble in meadows and median strips around Denver (I have pictures to prove this contention). There is a contemptible streak of puritanism in the noxious weed movement that focuses unduly on plants with ornamental merit. If you are reincarnated as a weed--hope that you are homely and you are apt to escape the weed-mongers scythe altogether!



Teucrium chamaepitys in the rock garden at Kew

 Another shocker for me was seeing this rather charming yellow flowered ajuga featured prominently in the Kew rock garden: for me this is an almost uncontrollable weed I remove by the wheelbarrow load from my home gardens. I don't think it was much a problem in cooler England where this may not set as much seed..


Araucaria araucana

 It is entirely possible that seed from very lofty populations of monkey puzzle trees might be induced to survive in Denver--in an extremely protected microclimate perhaps. I have seen a healthy specimen at Willard Bay Gardens in Utah...but we are not apt to have immense, graceful and obviously very happy araucarias in our parks as they do in the lawns at Kew. Location, location, location!



Delosperma cooperi in a glasshouse at Kew

But Delosperma cooperi, grown by the tens of thousands across Denver in just about any soil or exposure, encrusted for months on end with a solid mat of rosy purple flowers was represented at the Royal Botanic Gardens by this rather halting individual in a glasshouse. Location, location, location!

(I like to have the last say!)...

Euphorbs: mixed messages...

Exhibit number one: Euphorbia cyparissius 'Fen's Ruby'--a plant I brought back from a March visit to Chanticleer many years ago. I wouldn't want to be without this plant, and it is likely I shan't ever be without it (it is determined to stay put)...although it was recently removed from the Rock Alpine Garden for its unbridled exuberance...but between a wall and a rock or along a path, I find it is relatively easy to subdue. The Euphorbia clan is decidedly a mixed bag. Some are irrepressible weeds, others are rare as hens teeth. It's the weeds I'm concerned with....

Exibit two...Euphorbia nicaensis: looks just a tad weedy doesn't it? In my experience, it sees little and spreads modestly from the root...been waiting for a seedling to commandeer...In another garden perhaps it is a thug. For me, it is a prize. Although it has the typical chartreuse charms of the genus, I find its form to be pleasing and it has fall color to boot. Alas, it is has a local look-alike:

The picture above and the closeup below are of Euphorbia esula, one of the worst weeds of the northern Midwest and Rocky Mountain area...growing contentedly in a container provided by the city of Aurora. I could have posted pictures of this from all over Denver as well. Despite the fact that this is an undeniable noxious weed, little seems to be done to eliminate it in the Denver metropolitan area.

 Instead, the dreaded "donkey spurge" of the Mediterranean is the Metro areas culprit (an undeniable pest in the foothills, but hardly a problem in metro Denver gardens where homeowners love it). I do not seem to have a good picture of the much maligned Euphorbia myrsinites, which I have a grudging fondness for (and all kids seem to love it too, by the way: it is so quaintly reptilian). I am concerned that there is insufficient warning to homeowners (upon whose doors a rather threatening citation is being hung as I type this) that they are very likely to suffer severe lesions and burns removing the offending weed unless they take great precautions to protect their skin (let's not even talk about eyes--it can cause blindness)...
Why, prithee, is the rather attractive Euphorbia myrsinites being targeted instead of the much more invasive Euphorbia esula? Could there not possibly be that puritanical environmental extremists might have a hangup about ornamentals? Euphorbia myrsinites occupies a fraction of the range that Euphorbia esula has usurped in Colorado. Euphorbia esula causes devastating damage to range land and cattle: I believe this is a great example of the misplaced priorities and myopia that have so often hampered and compromised the environmental movement. Time and again they target horticulture rather than the real culprits that operate on a colossal, industrial scale. Let's begin by getting the damn E. esula out of the Metro area first! But then you couldn't hang warnings on doors--you'd have to actually go out and weed.

To end on a slightly more positive note...the above is a wonderful dwarf Euphobia capitulata from the Balkans, a plant I have loved for more years than I can say...why? it is so tiny, and so modest in its charms. Euphorbias are an acquired taste.

One of the largest genera of flowering plants, it is enormously polymorphic in foliage, stem and blossom. I end with my favorite of all Euphorbia, the succulent clump former of the high Drakensberg, Euphorbia clavarioides var. truncata. I took the picture above on an enchanting March day on Ben McDhui in the East Cape fourteen years ago. I doubt this shall be targeted by the weed police in the immediate future (thank Heavens!)--my two little clumps are not quite fifty cent piece in size yet...but just you wait, Enry Iggins!