</p> I'm sure that if you told the next fifty people you met that "there are trillium growing wild in Colorado", I'm sure not one in a hundred would believe it. The picture above was taken last weekend north of Steamboat. Oh, so many stories! I had camped in this area for the first time nearly half a century ago. A bear tried to get in our tent (we kept the bear prints for years on the outside of the tent.) I went back many times since then. Early in this decade a colossal wind knocked down tens of thousands of trees in the Zirkel Dome area. Spruce beetle populations skyrocketed, killing all the healthy trees, and subsequent fires wrought havoc as well: I wondered if our trillium survived there?</p> </dt> Western white trillium (Trillium ovatum) last weekend near Steamboat.</dd> </dl> Many did! I could have spent days looking through the woods and tabulating trilliums. They are really quite common in the Montane and Subalpine forests of northern Routt county. As I peered from a distance at the remembered hills, I saw that much of the range of this plant is indeed changing: one of the hills near Slavonia which was filled with unusual treasures had burned just a few years ago... Unlike the eastern white trillium (T. grandiflorum</em>) which looks so similar, this trillium grows in very cool areas, often blooming near snow. Not a plant to grow in gardens, but a treasure to find again in the wild.</p> </dt> Trillium with snow (Trillium ovatum)</dd> </dl> </p> </dt> Three leaf bitterroot (Lewisia triphylla)</dd> </dl> There are no end of special plants in Moffat and Routt counties: this looks very much like pygmy bitteroot (Lewisia pygmaea</em>) only it comes from a bulb and grows at lower elevations. The only place in our state where you will find this miniature bluebell is in Northwest Colorado: the blue is piercing. What a cute miniature. We did not have time to seek out our native Rhododendron albiflorum</em>: next time... It would take a good many blogs to do justice to our state. This weekend it will be Central Colorado, with some tundra time: maybe I'll bump into you? Have a fabulous Fourth of July!</p>
Red birds in a tree</p> Native plants usually summon up images of wispy, finely textured grasses or suchlike--hardly a glamorous novelty like red birds in a tree (Scrophularia macrantha</em>). This gorgeous native perennial is prospering in gardens across America and beyond, but is restricted in nature to just a few montane sky islands in southern New Mexico.</p> It was on Cooke's Peak, exactly twenty years ago this month that Allan R. Taylor and I had obtained the permission of landowners to drive up Cooke's Peak in Luna County to visit the famous grove of Arizona Cypress that grows there (the northernmost, and most cold hardy of its kind as it turns out). I noticed a penstemon-like plant that didn't look quite right in a few spots among the cypresses and collected a single capsule that was beginning to ripen. All Scrophularia macrantha</em> in cultivation across the world are probably descended from the seeds in that capsule plucked twenty years ago (a testament if we needed any of the power of horticulture to propagate rare plants).</p> Redbirds on a median strip!</p> Here you can see an especially showy specimen of this species growing on a median strip in Lakewood, where Greg Foreman transformed the idea of what could or couldn't be grown in public places. I nearly had an accident when I saw this enormous clump--almost six feet tall and even more across! In nature, most seemed to be only a few feet tall, as they are in many gardens. They start to bloom in late spring, and many still have flowers in autumn. Friends have commented that this is the ultimate hummingbird magnet.</p> Ever since this was first promoted by High Country Gardens</a> (where David Salman gave it its wonderful moniker) and later picked as a Plant Select</a> choice, hummingbirds have flocked to this gorgeous native in gardens across the West. In fact, I suspect that this and the many other red flowered agastaches, salvias and penstemons promulgated by Plant Select may be responsible for the dramatic increase of hummingbirds in residence in our lowland cities over the past two decades. When I was a kid, you never saw hummers in town except in spring and fall--Plant Select has provided a banquet that keeps many of them in town--and provides a haven for them in dry years when nectar in the high country is hard to come by.</p> There are hundreds of Scrophularia</em>s in Eurasia as well as North America--most of them brown or green in color. This is unquestionably the showiest. Fortunately, it still resides in its own family (Scrophulariaceae) whereas penstemons, paintbrushes, veronicas and many more former "Scrophs" have been put in the Plantain family. I don't believe the hummingbirds care, however!</p>
Hydrangea quercifolia</em></p> This time of year I am amazed to see spectacular mounds of Hydrangea</em> 'Annabelle' glowing around the metro area. That is one cultivar that has certainly made its mark, although one doesn't see quite as many of them as you would in a more humid part of the country. I've noticed a few other sorts here and there--including small plants of the blue species (I think the jury is still out on these when it comes to our climate however.). There is one particularly striking hydrangea that has really proven its mettle for many, many years at Denver Botanic Gardens. The Oakleaf Hydrangea (according to the USDA)</a> is restricted to just the eight southeastern-most states, and yet the plants shown above have persisted in a dense stand of English Ivy alongside Denver Botanic Gardens' Waring House for nearly 30 years.</p> Blossoms of the typical wild form</p> The common wild form has long, graceful flowers that form a bit of a cone shape up to a foot long. Like others in the genus, the fresh flowers are white, but age a lovely soft green. If you cut them and hang them in a cool dry spot, they can make wonderful dry flowers for the winter too!</p> Hydrangea quercifolia</em> 'Snowflake'</p> Growing alongside the typical form is a more compact flowered and smaller leaved cultivar that looks a bit more like the Eurasian species. It seems to have fared just as well over the decades, and makes for a nice contrast. All forms of this wonderful shrub turn glorious orange and pink in the fall, reminiscent of their native cousin Jamesia americana,</em> that grows everywhere in our mountains (the only member of the family that does).</p> Both cultivars together</p> Here you can see both cultivars growing alongside one another more clearly. Surely, if they can grow well in this most challenging spot, nearly swamped with thirsty ivy, imagine what it might do in a well prepared spot in your garden with some compost and TLC? We have another handful of cultivars of this wonderful plant elsewhere on our grounds--but not enough! Come to think of it, I have a perfect spot in my garden for one... I better go out and get it before you beat me to the punch!</p>
Winecups in Watersmart Garden</p> Strolling around York Street gardens this time of year, you are apt to see a bright rose red plant that resembles a geranium in many gardens. It is apt to be winecups (Callirhoe involucrata</em>), a favorite of many staff and keen gardeners in the area. Not a geranium at all, this is in the Mallow family, and another common name is "Poppy Mallow", although it's no more a poppy than it is a geranium. It is a native plant found sparingly on the Great Plains east of Denver, more commonly in the Midwestern prairies. It is a stellar garden plant that will survive with no supplemental irrigation once established...I see it occasionally as I drive around Denver--but not nearly enough!</p> Winecups in Highlands</p> Here is an amazing planting I found yesterday in Highlands neighborhood--easily ten feet across, completely filling one of those triangular hellstrip corners that are so often weed infested and neglected-looking (making neighborhoods look like slums). Here is a great alternative--a rock, a bit of Russian sage (Perovskia</em>) and an exuberant mass of winecups blooming for months on end--all with no supplemental water!</p> A closer look</p> This mass is growing in part shade--and the mound is almost two feet tallk, as opposed to the first picture in this series taken at Denver Botanic Gardens, in full sun--well less than a foot tall. It does need some room to ramble--but almost everyone has a spot where this can flourish.</p> Callirhoe involucrata v. tenuissima</em> Not everyone likes the hot magenta of the typical form of this species: there is a lighter, more pink form of winecups that is found originally in Mexico--sometimes classed as var. tenuissima. It does have even more finely divided foliage and a neater habit and the flowers often have a striking white eye--here seen growing in the Rock Alpine Garden as it transitions to the Gates Garden in the west. I am especially fond of this form, first introduced to cultivation by Yucca-do a few decades ago.</p> Closeup of tenuissima</em>.</p> You can see if you compare this with the next that var. tenuissima</em> is quite different in effect. Come to think of it, I think I need both in my garden! And I wish we'd see it a lot more everywhere in town: one of the toughest and most beautiful native perennials!</p> Closeup of var. involucrata</em></p> Here is a closeup of the typical form for comparison with the one above--both are really stunning! For sale in better Garden Centers (forget the Box Stores when it comes to native plants)..can be planted any time--just make sure it doesn't dry out in the height of the summer until established!</p>
Claret cup cactus</p> Earlier this year, the Colorado Legislature passed a bill designating</a> Echinocereus triglochidiatus</em> the official state cactus of Colorado. I'm one of those people who'd find it hard to settle on a single taxon as a favorite--especially in such a splendiferous and exquisite group as our native cacti...although we fellows (or at least those of us who aren't color blind) are known to love bright red flowers. And few flowers are as outrageously, emphaticalloy red as the claret cups. Of course, "claret cup" covers a number of species--and Colorado has at least four distinct taxa grouped under at least two specific epithets. Most of these are blooming right now at lower elevations throughout the state.</p> Last weekend three staff from Denver Botanic Gardens took a whirlwind trip to the San Luis valley to explore a unique habitat that contains some strange, and possibly novel taxa. The next morning we began our trek homeward, but took a side trip through a corner of the San Luis hills, a little studied corner of the state comprised of volcanic rock. As soon as we got out of the vehicle we were greeted with the bright red beacons of these amazing flowers.</p> Claret cup in habitat</p> This form has traditionally been considered a race of Echinocereus triglochidiatus</em>, the classic "claret cup", although some botanists have classed it as its own species: E. gonacanthus</em> because of its robust stems and coarse spines. Certain plants are so photogenic that no matter how many pictures you already have, you invariably take more! Such is the case with claret cups--I must have dozens of perfectly good pictures already, but who could resist these prickly mounds studded with such Christmassy red flowers? And the tufted, silvery artemisias that grow with them make such a wonderful setting, as do the thickly lichened stones.</p> Echinocereus gonacanthus</p> On such an intensely sunny day, you have to use every trick in the book to try and capture these gorgeous plants in their awe-inspiring setting.</p> Hunger cactus on the ridge</p> Claret cups were not the only cactus here--we found several other species, including this spectacular prickly pear that grew on the most windswept sites. It was heavily budded. I imagine by mid-week this will be a blaze of color!</p> And even more Hunger cactus</p> This picture better shows how thickly these grew. They undoubtedly would key out to be Opuntia polyacantha</em>--the commonest prickly pear in the state--although I find it is extremely polymorphic in its habit. I loved these high alitude specimens with such long, white spines!</p> Yucca angustissima?</p> The third remarkable succulent that abounded in these hills was a miniature yucca in peak bloom. The foliage was only a foot or less in length, and the flower stalks were under two feet tall. This formed incredibly dense colonies that must be impenetrable which we observed on the steep east facing slope of the mountain--really quite different from Yucca glauca</em> around Denver.</p> Red tepaled yucca</p> Some of the yuccas had quite dark reddish coloration on the back of their tepals--a wonderful trait to possess in a garden plant. And I know at least one local nurseryman who is propagating this very strain.</p> Dwarf huccas with Cuchulain</p> Ooops! Sorry--that's not Cuchulain! But his avatar on our staff, Mike Bone, curator of steppe collections and master propagator!</p> Penstemon auriberbis</em></p> A few hours later, as we headed towards the Wet Mountain valley, we saw wonderful displays of wildflowers including this bright penstemon that is almost restricted to Southeastern Colorado prairies.</p> The Research Department, who organized this trip, have to take advantage of the summer months of growing season to do their work monitoring and studying our native flora. We were lucky to join them on this productive jaunt. This year promises to be an "Year of wonders", and I have borrowed two verses from Dryden's "Annus Mirabilis" that resonate:</p> "In this deep quiet, from what source unknown</p> Those seeds of fire their fatal birth disclose"</p>
Purple Mountain sun daisy at City and County Building</p> For over a decade the Master Gardeners of Denver and I maintained a low water garden</a> in front of the City and County Building in the Civic Center of Denver. It was with mixed feelings that I saw this replaced a few years ago with a much simpler, and rather classic garden design. A few days ago, as I drove past, I was startled to see a familiar flash of rosy purple pink: Surely that's not "Purple Mountain Sun Daisy?" I stopped and sure enough, Osteospermum barberiae</em> 'Purple Mountain'--one of the first hardy ice plants to be promoted in U.S. horticulture--was making quite a show. This was introduced to horticulture by Plant Select in 1998</a>--and has gained a steady following across the country over the interim.</p> Closeup of Purple Mountain</p> If you are not familiar with this plant, take a closer look. Photographs have a hard time capturing the distinctive and unique color--somewhere between hot pink and rich purple violet. The color is fantastic, and everyone loves it. There is a slightly darker ring around the disk flowers that make it even more alluring, and it does change hue every so slightly over the days that it opens. The reverse of the ray flowers is a silky bronze color--important because the flowers close at night or in dark weather. And while it blooms most enthusiastically from late April to mid June, there are scattered flowers on this lovely plant all summer long. Did I mention it has leathery, dark green evergreen leaves?</p> Purple Mountain bedded out</p> I take more than a little pride that the park's staff and designers have chosen such a prominent spot to showcase a plant that was debuted at Denver Botanic Gardens in 1991 (a few years later High Country Gardens began to sell this from germplasm they obtained from us). And now I see it popping up here and there around town.</p> Bank planting of Purple Mountain</p> I took this picture of a mass planting at a bank a few blocks from Denver Botanic Gardens a couple years ago--I noticed it's still going strong and blooming spectacularly this year again...</p> I've seen wonderful plantings in Pueblo and Vail--two utterly different environments: the plant obviously has a wide latitude of cultural tolerance. I have friends who have grown it in Massachusetts and California. Truth be said, it does seem sensitive to fungal or bacterial damage in some gardens. If you've had trouble with 'Purple Mountain', do try Osteospermum</em> AVALANCHE (see below).</p> Osteospermum AVALANCHE in the Mordecai Children's Garden</p> If you have never visited the Children's Garden at Denver Botanic Gardens (thinking it was only for kids), do not pass go, do not collect $200 Monopoly dollars--get yourself down there pronto! You will find amazing spreads not only of this gorgeous South African, but of all manner of wonderful montane and alpine plants that thrive in theCildren's Garden's green roof soil mix.</p> Denver Botanic Gardens can be proud indeed to have debuted such an important and uncanny group of perennials. The annual Osteospermums are well and good--but these hardy sorts make plush groundcovers, and bloom for months on end. Perhaps you should include a few in your garden? Who doesn't need a little Purple Mountain majesty above one's fruited plains!</p>
By Colleen Smith, Guest Blogger</strong> Colleen Smith writes and gardens in Denver. She’s the author of </em>Glass Halo and </em>Laid-Back Skier.</p> We humans are no more exempt than the bees and butterflies and hummingbirds when it comes to plants: We’re attracted to their sweetness and beauty. We recognize plants as life. And so we shop. We wander through greenhouses and shuffle through nurseries, searching out plants. We are mesmerized. Hypnotized. Hortiholics. Even if you don’t fancy shopping, but you have the gardener’s genes, you probably enjoy shopping for plants. Shopping for a new swimsuit or a new pair of jeans usually proves depressing. Shopping for a car can require a bank loan and a boatload of anxiety. Shopping for groceries often seems like a necessary but mundane chore. But shopping for plants? A different story altogether. Purchasing plants sets the gardener’s imagination spinning, kicks up horticultural endorphins, benefits the community and the planet. When we support growers, we support growth. Plus, we just might harvest strawberries or love apples, culinary herbs or gorgeous cut flowers for nosegays. Our plants will add fresh oxygen to the air and suck up CO2. The Front Range’s premier plant-shopping extravaganza, Denver Botanic Gardens’ Spring Plant Sale looms on the not-too-distant horizon. Get your tickets for the chic and savvy Preview Party</a> May 8, or mark your calendar for the free admission public sale on May 9 and 10. Find all the details here</a>. Remember to bring your own wagon. Then enjoy the happy state of anticipation because shopping for plants is anything but depressing. Plants help heal us while they heal the world. </p>
Corydalis nobilis</em></p> </p> Fumewort may happen to be the accepted common name, but most of us prefer to call them by their Latin name: Corydalis. Some put the accent on the antipenult, others on the penult: either way--real gardeners will understand! These plants are hot</strong> right now. Dozens are available from specialist nurseries, often at exhoribtant prices. One of the showiest of the bunch, however, has a long history of growing at Denver Botanic Gardens, where several are blooming now. Here is a picture of one in the glory days--they're more modest in size lately!</p> Corydalis nobilis </em>in the wild</p> One of the many high points of a trip I took with Mike Bone five years ago to Kazakhstan at the behest of Plant Select was finally finding this familiar plant in the wild! Although we covered many miles in the Altai mountains both in Kazakhstan and Mongolia, we only found this one patch of the Corydalis</em> growing on a north facing talus slope not far south of the Austrian Road summit.</p> Corydalis nobilis</em></p> Here is that colony a little closer up.</p> Corydalis nobilis</em></p> And here you can get a better picture of a whole plant up close. There is something unique about the bearing of this plant . . . the graceful bluish fernlike tuft of leaves, and those clusters of bright yellow flowers with the darker spot in the center! People find this irresistible--whenever they find one at the Gardens they always comment on it.</p> Brunnera macrophylla</em></p> You can imagine my surprise when Tom Van Zandt, a member of the Gardens in Boulder, called me to tell me that his neighbor had dozens of Corydalis nobilis</em> naturalized in his garden! THIS I had to see...I drove up to Boulder yesterday, and was a little taken aback to visit the old Rockmount Nursery site I knew well as a child growing up in Boulder, chockablock full of Siberian forget-me-not (Brunnera macrophylla</em>). This last undeveloped corner of this famous nursery was purchased from Darwin Andrews, and the current resident has maintaned the site--removing weeds and allowing the plants there to coast on, entirely on whatever moisture comes out of the sky. There are some famous trees--state champions--growing here that I've visited in the summer: a giant Post Oak (Quercus stellata</em>) and an even more imposing Shingle Oak (Quercus imbricaria</em>). But I didn't expect to see literally millions of Siberian squill (Scilla sibirica</em>) which unfortunately had just passed over bloom. And large Peking lilacs (Syringa reticulata</em>) and many other exotics that had persisted with little care and no water for decades. Did I mention there were masses of Colchicums</em> in leaf--likewise naturalized, and several husky clumps of herbaceous clematis (Clematis integrifolia</em>) in the grassy opening between the woods. By the way, if you look in the back of this picture you will see some pale yellow glimmerings...</p> </p> Yes! Here is the first Corydalis nobilis</em>, in gorgeous combination with the forget-me-not: a combo any designer would pride themselves on!</p> </p> Everywhere I looked there were masses of Corydalis</em>, growing with amazing vigor!</p> Corydalis </em></p> The site was a rocky slope, not unlike where I'd seen them five years ago in Kazakhstan, albeit nearly two months earlier in the year.</p> </p> The owner of the home has approved of our obtaining seed from these colonies. It's highly unlikely you will find this corydalis</em> at our plant sale this year, or anywhere mail order I know about for that matter. But we shall make an effort to grow as many as possible. I can't wait to re-create this combination of corydalis</em> and forget-me-not at my home!</p> Notice the corydalis</em> in this last picture is coming up through English Ivy, likewise naturalized here! Boulder does get a few more inches of precipitation than any other city in the state below 6000'--although Boulder has had its share of drought years. Seeing all these plants persisting in cultivation after decades of benign neglect brings up the spectre of "invasiveness." I suppose the Brunnera</em> is growing so widely and thickly one would be cautious about planting this? I have grown Brunnera</em> many times--and it will indeed produce lots of seedlings in the garden, which I find pretty easy to remove. I think it's a question of finding a spot where you don't mind having them spread. There were many dozens of Corydalis</em> throughout the woods, it's true, but they have probably been growing at that site for half a century at least--probably more like a century. This is growing in dozens of garden I know of in the Front Range, and I have never heard anyone complain about its producing too many seedlings (there are always takers!).</p> What this really brings up for me is a major solution to the perennial question: "What do I grow in dry shade?": This is probably the most frequently asked question I've had over the decades. I can now respond enthusiastically: plant Siberian squill, Colchicums</em>, siberian forget-me-not and Corydalis nobilis!</em> And it is very possible that in a hundred years, you will have botanic gardeners like me marvelling at your low maintenance, xeric garden! Thank you, Tom, for showing me one of the great horticultural wonders of Colorado!</p> </p> </p>
</p> The "Green Roof" or eco roof concept has become a billion dollar industry in Europe, where storm water abatement and water quality are top drawer concerns. With the catastrophic flooding of last September fresh in our minds, we in Colorado should rachet up our concern. We are lucky to have a horticulturist coming to Denver Botanic Gardens to speak who has had extensive experience with eco-gardening at the University of Pretoria in South Africa.</p> Jason Sampson</p> April 19 from 1-4 p.m. at John C. Mitchell Hall, Denver Botanic Gardens</a> Jason Sampson, Curator, Manie van der Schijff Botanical Garden at University of Pretoria, will be talking about "Green Walls" (1 p.m.) and "Hybridizing Aloes" (2:30 p.m.). Please email me at kelaidip@botanicgardens.org</a> if you can attend either lecture so I can put you on the class list.</p>
Pasqueflower</p> There are pasqueflowers throughout Denver Botanic Gardens this week--especially in the rock garden. I have observed many interesting phenomena in my long career at Denver Botanic Gardens: the proliferation of perennials and alpines being perhaps my favorite. Don't get me wrong, I love annuals (and grow my share of petunias!): when I first came to D.B.G., annuals were the centerpiece throughout: Victorian carpet bedding. The Rock Alpine Garden (I was hired as its Curator 34 years ago last week) was the first lavish display of perennials at the Gardens, only followed by the Perennial Border proper (now the O'Fallon Perennial Walk) a few years later. Nowadays, perennials provide the backbone of practically every garden, and "alpines"--perhaps better described as rock garden plants--are nearly as ubiquitous: I hasten to point out that the distinctions "perennial" and "alpine" are both specious, albeit useful generalizations. Perennial is usually applied to larger herbaceous plants, and alpine to the tinier ones that are usually planted in alpine gardens or troughs. Almost all alpines are of course perennials, and there are plenty of coarse herbaceous giants occur on alpine tundra. Details, details! The larger perennials (think peonies or Oriental poppies) don't usually bloom prolifically until later in May or June thenceforward to autumn. March, April and May belong to the alpines, which are glorious throughout Denver Botanic Gardens right now, and will be sold in droves on Saturday, April 26 from 9:00 AM to 3:00PM in Mitchell Hall at the annual North American Rock Garden Society's gala sale. Don't miss it!</p> Alpine trough</p> The alpine plant sale this weekend will also feature a display of troughs--the term used to describe concrete planters designed to look like antique rock containers now used to grow tiny perennjials outdoors year around. Many members of the club (and staff of Denver Botanic Gardens) will be bringing these to show at the sale to give you inspiration on how you too might grow some of these tiny plants. Plant Select is also getting into the act with "Select Petites":</a> a new category of Plant Select plants chosen for their small size: these will be available at this sale as well.</p> Crevice garden at DBG</p> Here is a picture I took this week of one of the many crevice gardens that grace the Rock Alpine Garden and also the new Children's Garden: these gardens are ablaze with color right now:: full of tiny alpine gems: do come down soon to the Gardens to enjoy these jewelboxes: perhaps you have a spot in your own garden to incorporate a feature like this?</p> Delosperma sphalmanthoides</em></p> Here is a typical "alpine" gem you might find at the sale. I actually took the picture in my own rock garden last week--this Delosperma</em> is not truly high alpine where it comes from on top of Komsberg Pass, in South Africa. It certainly looks like a high alpine plant, and needs the conditions of a rock garden to grow in cultivation. This plant has special meaning for me because i first obtained it 25 years ago from John Lavranos as an unknown collection: I gave cuttings to the Huntington botanic gardens and subesequently it was identified as a plant new to science--the first such plant described from our collections! It has gone on to become a popular plant in Europe and back in its homeland as well--and since it is only known to grow sparesly in less than an acre of rocky ground in nature. I'll bet there will be some of this for sale next weekend!</p> Draba polytricha</em></p> I took this last picture last</strong> weekend of a trough in my home garden: this amazingly wooly crucifer comes from Turkey originally, and thrives in Colorado gardens. I'll bet there will be lots of this at the sale! It's been blooming since February, and will bloom into May--a long season indeed. As you can see, it came through the snow unfazed: one of the many benefits of growing rock garden plants is that they bloom long and early, and shrug off snow and even hail like their pleasant impediments. In our changeable climate, this is a charming trait. Come by the gardens and enjoy some of the hundreds of rock plants and alpines growing here and there throughout the grounds, but with special concentration in the Children's garden and the Rock Alpine Garden. Denver is renowned among American Public Gardens for our alpine collections--and perhaps now is the time you should see where you can't grow a few in your garden too!</p>
