Random sampling of Burr Oak Leaves</p> Our spring may have been the worst I can ever remember, but fall is shaping up to be extraordinary. Yesterday, towards the end of the amazing Pumpkin Festival at Chatfield I found myself wandering through the extensive windbreaks, most of which were planted twenty or more years ago by my friend Chris Hartung, who now runs an amazing nursery in Canyon City</a> with his wife, Tammy. It would be fun to walk the windbreaks with Chris and hear his stories: the trees have grown surprisingly well despite no irrigation, abundant bunnies, deer, elk and you name it in the way of herbivores. Even the "slow growing oaks" are getting some size despite the lack of irrigation! Burr Oaks (Quercus macrocarpa</em>) do not color brilliantly as most trees do in Denver: but they make up in rugged charm and wonderful leaf shape and acorn what they may lack in brilliance! Just look at the amazing variabillity in leaf color and shape in this very random sampling!</p> Burr Oaks at Chatfield</p> Denver Botanic Gardens at Chatfield is truly stunning: although the plant collections are still modest (the Visitor Center Garden--designed by Lauren and Scott Ogden, is world class, however, and large nevertheless), what makes a visit to Chatfield so gratifying right now are the wonderful vistas! The Rockies looming all along the West, the gently rolling countryside: it is our Secret Garden (although the tens of thousands of people coming to pick their pumpkins yesterday must have had an inkling! There were record crowds this year!)</p> Windrow of Burr Oaks: each one different!</p> It's great fun to stroll the windrows: every plant looks different. Some have already lost all their leaves, a few are still bright green. I wonder where the acorns were collected for these: are they from the Midwest? Or did Chris find a source from the wonderful Burrs that grow around Devil's Tower in Wyoming. On a recent visit to Gillette in early spring a few years ago, my hosts drove me up to the Devil's Tower and we walked around it (clockwise--the way you should walk around mountains of course!). This is the Westernmost colony of the tree in the northern Plains, and they were almost exactly intermediate between Gambel's and Midwestern Burr in character--some even stooling like a Gambels. The ones at Chatfield look more treeform (although still only fifteen or twenty feet tall at the max). I planted two burr oaks at my house about the same time Chris planted these and my Burrs are enormous now--one has to be over 30' tall and almost as wide and starting to take on the rugged adult form: three or four times the size and girth of these specimens: such is the power of irrigation!</p> Burr oak acorn</p> There were not a lot of acorns (the trees are yet young) and the ones I found were much smaller than the golf ball sized burr oak acorns I used to marvel at as a child in the park next to my house: those more than justified the common name "mossy cup" or "overcup oak".</p> An example of variability</p> This shows how variable the trees are: the one on the right was still mostly green, the one on the left is all brown and in the distance the burr oak is totally naked. All in proximity with what must be very comparable soil and exposure. Go figure!</p> Sprig of oak</p> For tree lovers, oaks and pines have a special resonance. If you've ever been lucky enough to see the massive burr oaks throughout the Midwest--all the way to the East Coast actually. Although I associate them especially with the magnificent oak savannahs around the Great Lakes and the rolling hills of the upper MIdwest. From a distance the white oak (Quercus alba) and burr oak look somewhat similar--but closeup the leaves and acorns are immediately distinguishable. Right now the handful of white oaks in Denver are a blazing, furious scarlet color (well worth their own blog!)--but even despite their superior fall color, it's the burr oak one finds here and there throughout our fair city. I believe the State Champion is just west of Cheesman Park--a massive creature that fills all the neighbors yards with leaves...(I know one of those neighbors and she's not to crazy about that tree)...</p> What sets this oak apart from many of Denver's street trees is its obvious drought tolerance. Chatfield's vast strings of windbreaks (so lovingly planted and cared for by Chris for years) are coming into their own: they make Chatfield a friendlier, more inviting place.. and they are teaching us a lot about the adaptability and variability of plants we should be planting more: the survivors!</p>
</p> Allium</em> 'Millenium'</p> Diane Reavis, one of our long time Plant Select committee members, observed that "we don't do a lot with the summer Alliums at Denver Botanic Gardens" as the committee strolled through the Gardens the other day. That got me thinking: I used to grow lots of Allium ramosum</em> in the Rock Alpine Garden, and I know there are some wonderful forms of Allium cepa</em> that bloom right about now. But with the notable exception of this spectacular clump of Allium</em> 'Millenium' in the middle of the Water-Smart garden, we really don't have very many right now.</p> Since this has been an area of great hybridization in Europe and the East, I have a hunch our staff will incorporate far more in coming years. You can probably guess what year Mark McDonough--who hybridized this showy beast--introduced it in? It has Allium glaucum</em> ancestry, and probably some A. ramosum</em> as well. I love the way it contrasts with the Devil's Shoestrings behind it (Nolina lindheimeri</em>).</p> </p> Allium senescens</em> v. glaucum</em></p> Here is one of the parents growing in my private garden. It was taken a few years ago this is only now starting to bud up and won't be in full bloom for several weeks. These form dense tufts of swirly foliage that look like a vortex, decorative in its own right. Thrives in almost any sunny, well drained spot. I've even had it over-winter in containers!</p> </p> Allium cernuum</em></p> One of the best late onions, however, is our native nodding onion, which you might encounter almost anywhere in our mountains below treeline. In fact, it grows pretty much across the United States from coast to coast. It is enormously variable in habit, size and flower color. It's worth trying this from various populations--you will find quite a bit of variation. This one was photographed in the Rock Alpine Garden.</p>
Yucca rostrata in Yuccarama</p> There are certain floral spectacles through the gardening year at Denver Botanic Gardens that are not to be missed: when the foxtail lilies (Eremurus</em>) are all in bloom early in June, for instance, or the Iris beds much of May and June... Well, right now we have the time of Yucca blossoming--and they are truly amazing any time of day--although they seem to glow with a special luminosity in the late afternoon. Yucca rostrata</em> may be primarily Mexican in distribution, but there are many robust and happy specimens blooming right now throughout the Gardens. I believe this my favorite!</p> Forest of tree yuccas</p> Ann Frazier, a volunteer, recently scanned this historical photo, showing the largest tree yuccas at the gardens a year or two after they were planted in the late 1990's. I blogged about these recently</a>...but it's worth revisiting these now that the flowering season is here...</p> Same yuccas taken today, July 2, 2013!</p> Do look back at the previous picture and see how dramatically these have grown in the last decade: I never cease to be amazed that Chihuahuan desert plants growing over 1000 kilometers south of here at lower elevations have the genetic tolerance to our severe winters! These have shown less frost damage than some of our native plants over that time! These were donated to us by Mountain States Nursery for testing and display, and I recall as Dan Johnson placed these thinking they would be the most expensive annuals we ever planted! I was wrong, obviously....By the way, the largest yucca in this planting is Yucca faxoniana</em>, and the more slender ones are Yucca thompsoniana</em>--both from the Chihuahuan desert in Texas and Mexico with roughly the same range as Yucca rostrata</em>.</p> Denver Botanic Gardens has a remarkable collection of many dozens of accessions of cold hardy yuccas that are located in many of our gardens. Now is a wonderful time to look at these--I have discussed a few of them in yet another one of my blogs you can find by clicking here.</a> And another one here</a>! As you might have guessed, I like yuccas! I end my little disquisition with a tribute to our ubiquitous, overlooked and sometimes maligned Yucca glauca</em>: Last May I drove through vast forests of this species in the Oklahoma panhandle and was dazzled by their heavy blossoming. Among the mostly creamy or ivory flower stalks were many that were stained quite deep pink. It was a dream of Claude Barr's to find a truly red yucca: I think these are well along the way to that goal! Alas, I was unable to collect that trip--so perhaps you can be the one to locate and introduce that holy grail?</p> Red stained Yucca glauca in Oklahoma panhandle</p>
Succulent sculptures at entrance to cactus and succulent greenhouse, Gothenburg botanic garden. The Swedes have a great sense of humor. I have been lucky to visit many of the world's great gardens: I shall never forget an April visit to Savill Gardens: millions of daffodils in bloom and me (just like Wordsworth's poem!). Royal botanic gardens Edinburgh on a perfect spring day. And I have now visited Gothenburg botanic garden again--after nearly 20 years absence. Many of my plant addicted friends agree with me that this may have the finest collections of Temperate plants on earth, grown to perfection and displayed with great artistry. Gothenburg ROCKS! And I'm here at the perfect time for their mind boggling bulb displays...a tiny fraction of which I shall share here with you... Anemone nemorosa coming into full bloom in woods all over Sweden: floral symbol of Gothenburg botanic garden...(sublime!) Before I do that I thought I should show you the wood anemone that is blooming by the million everywhere in Sweden right now: these were taken at Gothenburg: this is the floral symbol of that garden. Not bad, eh? I think Denver Botanic Garden should have a floral symbol...the Pasqueflower, perhaps? Easter daisy? Let's hope we pick as wisely! Carl Skottsberg, first director of Gothenburg Botanic Garden: a great botanist and visionary leader Gothenburg has had more than its share of brilliant leaders, starting with the first (who is honored on this medallion in the administrative building). Per Wendelbo, who led the garden in the middle of the last Century, is credited for really elevating its collections and stature--he was Norwegian by birth, and died tragically in a traffic accident in middle age. He picked out Henrik Zetterlund as horticulturist, who has been the guiding spirit of the garden ever since--and whom I will honor in my next blog--showing him in his native habitat in Götene where he has a weekend home.... Tanacetum leontopodium, a wooly composite from alpine heights in Central Asia--one of thousands of fabulous plants blooming right now at Gothenburg An alpine daisy, challenging to grow outdoors in Sweden, grown to perfection in one of the many alpine houses. Mats Havström, curator of Herbaceous collections took Sunday off to show us around behind the scenes: one of many young talents who are maintaining the momentum of Per Wendelbo's dream. One of the many talented young staff in the Dionysia house, showing a group of us around last weekend. Iris linifolia, a rare Central Asian Juno iris grown to perfection in one of the bulb greenhouses ("behind the scenes"). I doubt you would find a FRACTION of the plants in this botanic gardens' collections anywhere in America--public or private. I am a big fan of Juno iris--and Gothenburg has one of the best collections along with Kew. We grow these outdoors, however: Gothenburg is generous and has shared many bulbs with us over the years. It is possible that some plants in your garden trace indirectly to them as well! Iris graeberiana x magnifica, at height of bloom in the public bulb display I was charmed by this hybrid juno--which I suspect would grow gangbusters in our xeriscapes. Anemone biflora in its dazxzling scarlet phase--in the public alpine house display I have admired this bulb in books for decades: what a treat to see it in "the chlorophyll" (plant equivalent of "in the flesh") Androsace (Douglasia) idahoensis--a very rare native American alpine grown to perfection in the backup alpine collections. Don't look for this anywhere in American public gardens--you will not find it. There are literally hundreds of American wildflowers growing throughout Gothenburg, a distressing number of which are NOT being grown by American botanic gardens. Sometimes we forget that botanic gardens should be about plants (ahem!) instead of distractions...but I am getting on my soap box. Sorry! Primula renifolia, the rarest primrose in the Vernales section, recently introduced from Caucasian cliffs by Gothenburg staff. They would not be thrilled that I'm showing this a big past peak of bloom--but this is a plant of great pride: the most unusual of its section and a spectacular new garden plant. They should be proud. The public is flocking to visit the bulb collections, although the day was blustery... Their garden is loved by the citizenry. And botanic garden afficianodos around the world make pilgrimage to Gothenburg: our Mecca! One of many dozens of species of Fritillary blooming now--all meticulously labeled. Some of us are proud to be Frit Freaks--although many in the genus are chequered brown and green and invisible to ordinary folk. Too bad for them! Rare Asiatic saxifrages in the porophyllum section, some still unnamed after decades in cultivation. You will not find these at your local Wallmart, incidentally... More treasures...ho hum..... Most of the dionysias were finished blooming (their flowers trimmed off to prevent rot)--but Dionysia khuzistanica still glowed in the Dionysia house. Just a tiny fraction of the treasures in a few of the many glass houses--and there are acres of rhododendrons, trees, perennial borders, and a rock garden with hundreds of vertical feet of relief--it would take an encyclopaedia to show it all: you must simply make Gothenburg a destination...but don't expect to see it all--especially not in just a single day!</p> "...And haply then That future country lost its gloom; More lovely in that world than this, Immaculate the white lily grows, And perfected we walk in bliss."</p> Hortus Paradisi</em>, William Bell Scott</p> More pictures from Gothenburg this week on this blog....</p>
Chilean blue crocus (Tecophilaea cyanocrocus) This </strong>should get your attention: after flying from Denver to Chicago, Chicago to Copenhagen, Copenhagen to Gothenburg, Sweden--we found ourselves in Eskilsby (a village not far from the airport) where we were driven to Peter Korn's amazing garden--and this was one of the first plants greeting us our first morning! Long thought extinct in the wild (it has recently been rediscovered), the dazzling blue Chilean "crocus" (which it is not) is one of the many success stories of horticulture--where rare plants have been propagated and even used to repopulate the old habitats! In Peter Korn's bulb house Here you can see the same plant in habitat--in front of Peter--in his special greenhouse for growing bulbs. Arum korolkowii This was one of my favorites in the bulb house--an aroid from central Anatolia which I am growing as well. I hope my form is half as good as this one! Bellevalia sp. in the bulb house Dozens of bulbous irises, fritillaries, narcissi and many more bulbs were blooming: I was enchanted with this Bellevalia--a genus allied to grape hyacinths. Logs designed as beneficial insect hotel Even the practical things around Peter's garden are attractive--he uses these logs to house beneficial insects that help keep the bulb collection clean. Cottage at top of Peter Korn's garden The garden is vast: these are just a few glimpses of some of it. There are actually many dozens of plants coming into bloom--but by May it is a blaze of color. We intend to revisit in a few weeks and see the progress of color in the alpines here... View of Peter Korn's rock garden from above But the sculptural forms of the landscape are beautiful in their own right. Much of this area was covered with dense forest before Peter began to clear it for the garden. It now has the rugged look of alpine tundra. It has been carefully crafted so that alpine plants can grow here much as they would in "nature" (which this closely approximates).. Another shot of alpine tarn in Peter Korn's garden If one didn't know better, one might easily think this was a picture taken on an alpine summit! View of Peter Korn's rock garden Pathways and benches are provided throughout to make it accessible to the many visitors who come to admire the views and the throngs off alpine flowers. Peter Korn's book on his garden: soon to be published in English Peter has written a book describing the philosophy behind this garden, full of beautiful pictures of plants in the wild and in his garden. He has had this translated, and it will be published in the next few weeks... I joined the director of the Botanic Garden in Tromsö, Norway (the northernmost botanic garden in the world) and Kit Strange, horticulturist at Royal Botanic Garden, Kew to speak as part of Peter's biannual conference he organizes in the nearby village. I have some more pictures from Peter's and greater discussion at another website... This is the beginning of a several week adventure I will be sharing with members: visiting Scandinavia in springtime is a great luxury and pleasure--and soon we are headed to Germany in pursuit of even more beautiful gardens, following spring in the European heartland!</p>
Opuntia cycloides at my house last fall Since there will be no lilacs breeding out of this year's dead land (check the last paragraph of this Blog if you don't recognize the reference!) we must make lemonade out of our lemons! And succulents RULE! Several groups of plants are coming through this rather horrific winter in great form: almost all native plants, alpines and succulents--especially cacti, agaves and yuccas seem not to have been fazed at all by the catastrophic late spring frosts that have laid so many flowering trees, shrubs and bulbs low. Yuccarama (Yucca faxoniana and Y. thompsoniana) I doubt there are many visitors to Denver Botanic Gardens (and literally millions of people have walked by these) who haven't noticed the sculptural forms of Yuccas outside our maine Education building. When Dan Johnson first had these delivered over a decade ago from Mountain States Nursery--I was sure they would be the most expensive annuals we had every planted: I was wrong on both counts--they were a gift so they cost nothing. And they have been resoundingly, gloriously perennial! And this year is no exception. They are our permanent sculptural exhibit! And they laughted at this spring's shenanigans... Opuntia engelmannii in the Rock Alpine Garden The "average person" is probably oblivious to the enormity of the damage inflicted last week by the 7F low with little snow: I think this is the greatest spring damage I have seen inflicted in my 34 springs at Denver Botanic Gardens. So I am focusing more than ever on that graceful ballet--as the opuntias all over the gardens gain color and turgidity over the next month or two and build to their spectacular bloom season: Looking at these and our rock garden and native gardens, I think...you know: they look good as ever! P.S. Afterthought: Several friends of mine have been quoting T.S. Eliot's Wasteland, which I have hyperlinked for your convenience...which many of us philologists puzzled over as youngsters in school: this long poem opened the floodgates to gnomic, mostly incomprehensible modernist "poetry" that (like Marianne Moore) I too dislike...the first sentence of which I have filched for my starter. I sort of like Eliot's most famous poem--although I hate what it has inspired subsequently. Give me Keats or Auden or Browning any day! </p>
Iris 'Katharine Hodgkin' In the last few weeks, a few crocuses here...a few snowdrops there...it's been slim pickens! But suddenly with the last few warm days the Gardens are practically exploding: each day brings dozens more flowers. I've seen the first daffodils blooming gloriously inside the Mordecai Children's Garden as well as on the parking berm. Waterlily tulips are opening up everywhere. There are Magnolias opening up around town, Cornelian cherries are at their peak and the apricots and almonds and other early Prunus</em> are teasing their first buds open. Soon we will have the whole nine-yards--Spring in her full glory parading everywhere. This magic moment, just before the figurative floodgates burst--this is perhaps the most perfect moment of the year. The garden is cleaned up and everything is shiny and promising and new. And this is the time when the glorious throng of reticulate irises are bursting into bloom here and there throughout Denver Botanic Gardens. closeup of Iris 'Katharine Hodgkin' If you grow but one reticulate iris, may I recommend 'Katharine Hodgkin'? I tell her full story elsewhere more expansively. Because she is a hybrid between two rather distinct species, she possesses what botanists call heterosis</strong></em>, or hybrid vigor. She has formed wonderful clumps in the O'Fallon Perennial Walk that are in peak form right now. Our horticulturists have planted her liberally throughout both sides of York Street, so expect her to be ever more evident in future years. If you look carefully at this closeup, you will see some streaking. Undoubtedly due to some of the genes between the two parents struggling, as it were, in the offspring (either that, or perhaps a virus. I hope it's the family squabble rather than the latter!). Here are pictures of the two parents: Iris winogradowii Surely the rarest, and one of the most mythical of all iris is this, the yellow reticulata</em> cousin from the Caucasus. Now listed in the IUCN Red Book of endangered species, this is only found in a tiny part of an alpine mountain range--only a few hundred plants persisting in nature. Fortunately, there are thousands in cultivation (you can even buy them mail order rather reasonably!). If you do choose to spend a few hundred dollars on these, be aware that this species needs a rather rich, acid soil in part shade that never dries out. This is not for the beginner! Iris histrioides 'Major' Here is the other parent: Iris histrioides</em> is only known from a few mountain summits in Turkey, but has been grown and distributed by Dutch nurseries for almost a hundred years. We have had it for over twenty years in the Rock Alpine Garden where this was photographed a few years ago. I regard this as the most sumptuous and magnificent of the reticulate species. Alas, it is hard to find nowadays in catalogs and does not always perform well in many people's gardens. So you may have to settle for one of the dozens of true Iris reticulata, </em>which are pretty wonderful as well. I am intrigued how 'Katharine Hodgkin' manages to transform the dark blue of histrioides</em> into a translucent, azure sea blue-green. The yellow qualities of winogradowii</em> are expressed through the chartreuse undertone and those wonderful golden patches. In painting, blue and yellow produce green--things are a tad more subtle and complicated in flowers. There are other hybrids gaining currency in the trade, but 'Katharine Hodgkin' seems thus far to be the most subtle combination and most readily available. I finish the blog with a glimpse of the enormous clumps of this you can find throughout the O'Fallon Perennial Walk here and there this week. I am dazzled to see how many different bulbs have been packed into this garden by previous horticulturists, and how well they have persisted despite the intense planting in this amazing garden. I know these massive clumps have inspired me to plant lots of this terrific bulb in my garden. What better way to celebrate spring as it shifts into high gear! vroom Vroom VROOOOOOOM!</p>
Winter is almost over, however there are still lots of options for enjoying the Gardens. Be sure to see some of the thousands of spring bulbs that are starting to bloom throughout the Gardens! The Mordecai Children’s Garden just opened for the season. If you have kids, the Children’s Garden is an obvious choice to visit because of the swaying bridge, the mini-theater, and the view of the Gardens and the Rocky Mountains from the Lookout. Even if you don’t have children, the Children’s Garden is a really great example of a large scale, green roof alpine garden. The Mordecai Children’s Garden is conveniently located across the street from our York Street location and is open March through November. If you live further south, Denver Botanic Gardens at Chatfield is another good choice. I also recommend Chatfield if you want to escape from the city for a while. Denver Botanic Gardens at Chatfield is a working farm, with over five acres dedicated to growing produce for our Community Supported Agriculture (CSA) program. The area also has significant historical interest, including the Hildebrand Ranch, the restored dairy barn and silo, and a one-room 1874 Deer Creek Schoolhouse. Our Chatfield location is at C-470 and Wadsworth. My favorite time to visit Denver Botanic Gardens is right after it snows. Everything is white and sparkly. There’s less foot traffic through the Gardens. Everything looks different under a coating of snow. Lots of shapes and textures in the Gardens keep things visually interesting. The Japanese Garden in particular is stunning in the snow. This time of year, you can even sometimes see flowers poking out from underneath the snow. Membership to Denver Botanic Gardens has great value. In addition to helping make Denver a better community, supporting children and adult education programs, supporting our research on Colorado plants, and generally helping us achieve our mission of connecting people to plants, membership gives you free access to all of these locations: York Street, Mordecai Children’s Garden and Denver Botanic Gardens at Chatfield. Kim Brokling, Membership Coordinator</em></p>
</p> </p> It's snowdrop time again! Surely, no plant is more intimately associated with winter flowering (okay, okay--Christmas roses may be!), and none have developed such an enthusiastic folowing: there are many specialty nurseries that sell dozens, even hundreds of kinds of snowdrops. Almost exactly a year ago I told the story of a snowdrop that fetched hundreds of dollars at Ebay auction. But truth be said, all snowdrops are precious this time of winter!</p> </p> Galanthus elwesii at Denver Botanic Gardens</p> The plant that now constitute our most robust colony behind the Succulent House along the Cheesman gate were originally used as "fillers" in a lobby court display: I rescued them and planted a couple dozen bulbs some twenty years ago. Each bulb has proliferated and this is now beginning to make quite a spectacle. Starting up just now (go check it out!). Here is a closeup of the commoner species that is abundant in the wild across much of Europe. I have grown this for over a half century at various homes--it spreads abundantly in Colorado as well--but believe me, this isn't a weed. You can always find homes for this plant. I remember this as a child in my parents home--just a few clumps here and there that spread to cover square yards by the time I was in college... Here you can see now Sandy Snyder (who worked at Denver Botanic Gardens for 17 years in the 1980's and 1990's) has managed to naturalize one of the tougher sorts in her sparsely watered buffalo grass in sun! Generally, they are recommended for shady spots where they get periodic irrigation, but many species are Mediterranean littoral plants that grow in areas that have no water from April to November. I suspect we could find sorts that would thrive with no supplemental irrigation. Three of many books recently published about Snowdrops: </p> </p> </p> By the way, if you Google "snowdrop" you will find a host of novels, mysteries and other books named for these winter beauties--they are obviously popular--especially in Europe. By the way, all the snowdrop monographs have glowing reviews--and the prices are beginning to get astronomical--obviously the time to invest in snowdrop futures! Remember to order some for planting next fall (the plants of course--not the books).</p>
Yes, Virginia...pampas grass (Cortaderia selloana</em>) does indeed grow in Denver...although not in great numbers. Observant visitors will have noticed them dotted here and there at the York Street gardens, and I have seen another half dozen driving around Denver. The one above is right next to University Avenue, and constitutes a minor traffic hazard as grass-afficionados notice it and swerve! I suspect the owners purchased it via mail order, since these are rarely sold locally ("pampas grass is not hardy" according to most pretty well-informed nursery folk. And I agree, most are not. Only the dwarf, high elevation forms are apt to be hardy here, and these are hard to find). Most Coloradoans probably don't know that pampas grass is a pestiferous weed in California--but then one man's weed is another man's treasure. I doubt that this will ever pose much of a threat in our climate. I share this picture to show that much of the creative work of plant experimentation is undertaken by home gardeners. We at the Gardens sometimes have to run to keep up! Here you can see from closer up the silky, silvery color that true pampas grass has seemed to perfect. If you have driven parts of Texas you are sure to have admired pampas grass--a popular landscape plant in that state. I used to drive down at Thanksgiving each year, and the clumps of pampas here and there along the way were like mile posts, or sentinels that cheered the trip. Their fluffy seedheads are amazing when they puff up. Alas! A well established clump is so massive that cutting it back each year is a chore. This is one of the hazards of growing large grasses anywhere. Confusingly called "hardy pampas grass" (a paradox if you think about it...), this is the most commonly planted giant grass around Denver. I am sure half the people who grow it think it is pampas grass, and if you look up and compare, you will see there is a family resemblance. But while the TRUE pampas grass comes from South America as the name suggests, Ravenna Grass is from the Mediterranean. This still grows abundantly in the coastal marshes near Ravenna I've been told. This is by far the most vigorous and giant of commonly grown grasses, and a large clump will often produce vigorous seedlings nearby that should be dug while young. A large clump needs a front end loader to move or remove...be warned! Until recently it was classed as an Erianthus</em>, but has been put in the same genus as sugar cane in the last decade or so (Saccharum</em>). Sugar cane has helped make Brazil energy self reliant. Maybe this vigorous grass has biomass potential? The group that has been exploited most for that in America is another genus altogether, however... There are hundreds of cultivars selected from the various species of Miscanthus</em>--which is also often sold as hardy pampas grass. They are hardy enough but the name is taken, I'm sorry. A great deal of research is being done on these because of their famous C4 metabolism which allows them to accrue enormous biomass in short periods of time. Miscanthus have nevertheless been practically banned in much of the eastern U.S. due to their propensity to produce colossal seed crops. I have yet to see a seedling appear in Denver outside, so I think we can grow these without guilt--except that these are the most water demanding of these larger grasses. Don't try them in your Xeriscape! My current favorite giant grass is native not far from us here in the Rio Grande Valley. Plant Select has chosen to feature this plant in 2006 and I can vouch for its toughness. The plant you see in the picture is in my garden, on very sandy soil where it bakes for months on end and gets precious little water. Even so, it makes a fabulous fountain of golden seedheads that persist through the winter months. Indeed, all of these pictures were taken this morning, January 24. The greatest reason to grow these pampas grasses (and their pretenders too!) is that they provide drama, beauty, movement and interest in the depths of winter for months on end. If you grow them, please resist cutting them back until February so we can enjoy their splendid display! But do cut them back hard so that the new growth will be fresh and green for the coming year!</p>
Xeriscape sometimes summons images of oceans of gravel and harsh, stickly, pointy plants that stab, slash and terrorize homeowner associations. A primrose? Really? Well, there are even primroses that can do with much less water than many people pour on their gardens, and the oxlip (famous in English Literature--even Shakespeare writes about it!) has proved itself for decades in a number of local gardens. Thanks to the Plant Select program, this and a host of other unique plants will debut across the country this spring. Oxlips do best in at least a half day's shade, but given a rich soil, mulching and occasional good watering, they will even grow in full sun in Colorado. They combine especially well with graceful, brilliant blue flowers like the Siberian squill pictured above. Although quite widely distributed in the foothills of the Southern Rockies, I have only stumbled on Scott's clematis a few times, so I suspect it is not exactly abundant. It has been produced abundantly by Plant Select propagators this past year and you should be able to find it in local garden centers this spring. The nodding, lavender bells vary from almost gray to a dark, almost black blue in some forms. As you can see, it makes a compact mound with those irresistible blue bubbles visitors at Denver Botanic Gardens simply have to squeeze...speaking for the plant, please don't! This clematis belongs to the "Sugarbowl" section of the genus (sometimes classed as its own genus: Viorna</em>) which includes a dozen or more of the rarest and most beautiful herbaceous clematis. This is likely to be the most drought tolerant of the lot--and the flowers last for much of the spring and early summer: we have had flowers into the autumn on larger plants--and the seedheads are a bright gold and almost as decorative. This plant is a must have for anyone interested in growing xeric plants. The "alumroots" (a dreadful name), or coralbells (whew!)</em> are entirely restricted to North America, mostly concentrated in the Western States and Appalachians. They have been intensively bred for foliage color by Terra Nova nursery in recent decades. I love the wonderful lacy flowers that brighten up dark cliffs all over the west. This is one of the most restricted in nature, but most accommodating in the garden. These three plants are the first sampling of Plant Select Petites, an expansion of Plant Select which seeks to provide more compact plants for the more intimate setting many of our more modern urban and suburban patio gardens, permanent outdoor containers and ever popular rock gardens which have become a hallmark of regional horticulture. There are another five outstanding introductions that continue to expand our regional palette of adapted and gorgeous plants that provide year around interest with less fuss, water and grief. I will write more on these later this spring... But I believe a trumpet blast is merited at the start of the new year for a new facet of this extraordinary program that has put tens of millions of wonderful plants into gardens across America and beyond. One of my favorite maps shows precipitation in North America where 20" or less is shown in red shades and 20" or more annual precipitation is progressively bluer. The east half and far left coast of America are bluish to be sure, but much of the middle and all the West except the mountain tips is painted in bright pink shades--nay! much of it quite red or deep vermilion. Drought is the norm</em></strong>. Each snowfall lulls us into complacency--but do remember, we live in a semi-arid region in which prolonged, deep drought is not an unusual event. Stop watering for a week or two in summer and you'll figure it out if you haven't yet. If our gardens are to survive into the future, it behooves us to develop a palette of plants that will be viable in our progressively more water restricted landscapes of the future. Thank you, Plant Select for leading the way! And keep up the good work.</p>
