While on one of my scouting tours through the Gardens, Mike Bone, curator of steppe collections and one of the horticulturists that manages the Steppe Garden</a>, informed me that the red hot poker plant (Kniphofia stricta</em></a>,</em> also known as a torch lily) had some interesting fasciation going on in the flower stalks in the Steppe Garden.</p> </p> The torch lily flower stalk is twisting, and some flowers are divided into two. These are some common symptoms of fasciation. Another symptom is a flattened flower, which can be seen in the blanket flowers (Gaillardia aristata</em></a>) in the Ponderosa Border just east of the UMB Bank Amphitheater. Other symptoms of fasciation include a flattened ribbon-like stem, bushy growth or twisted stems.</p> Fasciation is typically a mutation or deformity that occurs in the meristem of a plant. Meristems are where cells begin to form – similar to stem cells in humans, these cells divide and then specialize, becoming the cells that make up the leaves, stems and flowers. Sometimes a mistake happens, resulting in an abnormal growth. These mistakes can be caused by anything from a defect in the DNA code in the plant, to a viral infection, to insect damage. It can even be something environmental that causes this. Because there are so many different causes, there is no one cure.</p> In some plants, like the cockscomb flower (Celsoia cristata</em>), this mutation is transferred by seed, allowing us to enjoy the unique, rooster comb-like flowers year after year. In others, like the torch lily or blanket flower, it is a physiological response, and typically will revert back to “normal” in later flowers or next season. If you’re not keen on how it looks, pruning it out is an option, as this mutation doesn’t generally affect the health of the plant. Otherwise, enjoy the funky flowers and stems!</p>
Water means life everywhere on Earth. But people in semi-arid regions understand this with a clarity born of living in time-step with the rhythmic greening and re-greening of the landscape around them. Anyone who has experienced the sepia-toned end to a Colorado winter has marveled that any flush of life could regenerate from such a hunkered-down thirst. And while our native plants are typically drought-tolerant, the human need of food, fiber, and an inviting shade tree, is less so. To meet these needs, early settlers in many parts of our state tamed the waterways with canals, moving water from mountain to plain, shortening the beat of time during which crops, street trees, and lawns had to go without water. Over time, plants, animals, and people have coalesced along these canals; these ramifying arteries that literally, and in many ways spiritually, sustain life along their banks.</p> The 130-year-old High Line Canal is one such artery, spanning 71 miles from the foothills to the plains, traveling through urban and suburban areas in Denver and the surrounding region. Since 1883, the Canal has been a part of the fabric of the region. The Canal draws water from the South Platte River, beginning at a diversion dam in Waterton Canyon near Littleton and running northeast to Green Valley Ranch. What results is a connective corridor that wends itself through various habitat types, from rugged and wild riparian stretches in the western canyon, to areas reminiscent of native shortgrass prairie in the east. The Canal corridor also passes through many highly developed areas, providing easily accessible green space to thousands of people. A pivotal point in the history of the Canal occurred in the 1970s, when Denver Water opened its maintenance roads, previously patrolled by early “ditch-riders”, to the public. The Canal trail now serves as a recreational hub for walkers, runners, bikers, and horseback riders in the region.</p> From a botanical perspective, the High Line Canal presents an interesting puzzle. Human settlement along the Canal has led to conversion of the surrounding native ecosystems to other land uses. Much of the Canal’s stretch runs through what was historically flat to rolling plains underlain by sandy to silty soils. The grasslands supported native shortgrasses such as blue grama (Bouteloua gracilis</em>) and buffalo grass (Buchloe dactyloides</em>) and a diversity of forbs such as sand lily (Leucocrinum montanum</em>) and scarlet globe mallow (Sphaeralcea coccinea</em>), to name a few. However, increasingly, the Canal’s greenway is surrounded by a built landscape of housing, businesses, and roads. And while there are often pockets of green space that punctuate the built landscape in the form of parks and gardens, these areas may be planted in monocultures (think Kentucky Bluegrass lawns) or contain cultivated plants that are not representative of the region.</p> The question then becomes, what exactly greens this greenway? Botanical staff and volunteers from the Gardens are spending more than 50 field days on the Canal this summer working to answer this question.</strong> (Look for us out on the Canal wearing blue “Researcher” vests, and feel free to stop and ask questions!) We are making plant collections and taking quantitative ecological data on plant communities along the Canal’s entire length from May to September 2018. The Gardens is working on behalf of our funding partner, the High Line Canal Conservancy, which will use the survey data to inform management decisions (see the Conservancy’s website</a> for more information on the Vision Plan for the Canal).</p> So far, our early spring surveys suggest that the flora along the Canal represents a mix of native and non-native plants. For example, it is typical to find native chokecherries (Prunus virginiana</em>), cottonwoods (Populus deltoides</em>), and coyote willow (Salix exigua</em>) mingling with non-native buckthorn (Rhamnus cathartica</em>) or honeysuckle (Lonicera tartarica</em>) along the banks of the canal. There have also been some unexpected native gems, including the uncommon Blue Ridge carrion flower (Smilax lasioneura</em>), which is present in only a few counties in Colorado but was happily growing along the trail in Waterton Canyon! When the data are in, we expect to uncover interesting variation in the make-up of the Canal’s plant communities in relationship to both the west-to-east ecological gradient, and the wild-rural-urban matrix that surrounds the trail. Stay tuned for updates as the field season unfolds!</p> Excerpted and adapted from original publication in Aquilegia</em>, the quarterly publication of the Colorado Native Plant Society.</p>
Denver Botanic Gardens recently installed four solar-powered atmospheric water harvesters – three at York Street and one at Chatfield Farms. Using the power of the sun, these SOURCE units accelerate the condensation process to convert water vapor into water.</p> All but one of the harvesters, which are made by Phoenix-based Zero Mass Water</a>, are helping irrigate plants. The other offers visitors to the York Street location the opportunity to take a taste! Each SOURCE will generate between five and seven liters each day (not quite two gallons), storing up to 30 liters (almost 8 gallons) each in a built-in tank.</p> This is one example of many partnerships the Gardens has with entrepreneurs as well as government and corporate entities to showcase and test water-efficient innovations. These are the first SOURCE units to be incorporated into irrigation. The Gardens is showcasing this technology as a potential solution to growing vegetables in areas without reliable fresh water supplies.</p> Here is more information on other Gardens water-efficient partnerships, programs and initiatives</a>.</p>
Mirroring the natural alpine and woodland habitats that the Rock Alpine Garden is inspired by, spring is a great time to walk through this garden. Both alpine and woodland plants bloom early in the year in response to the physical restraints of their native environments.</p> Alpines are programmed to bloom as soon as the snow melts in their native environments. Plants you might find on Loveland Pass or Trail Ridge Road blooming in late June or July bloom in Denver in April.</p> One of the best areas to see true alpines in the Rock Alpine Garden is the crevice garden on the south side of the main path — Draba</em>, Potentilla</em> and Erigeron</em> bloom in tight north facing crevices. Additional areas to see true alpines are in the various troughs scattered through the garden — Silene acaulis</em>, Polemonium viscosum</em>, and Hymenoxys grandiflora</em> should flower by the end of the month. The north side of the Cactus and Succulent house is another great place to focus on the early flowers of Draba</em> from Eurasia, and the mat and cushion forming plants that creep and crawl amongst the rocks.</p> One of my most favorite “secret areas” in the Rock Alpine Garden is the far southern path that takes visitors along the far southern edge of the garden along the perimeter fence. It passes through some of the best woodland areas in the rock garden. Take time to enjoy the full variety of plants in the densely-planted area. If one enters the path near the crevice garden at the east entrance near the South African Plaza and you continue on this path, it will take you into more woodland areas of the rock garden which rarely get the visitation they deserve. Passing down a slight slope take in the various Lenten roses (Helleborus</em>) and woodland sweet peas (Lathryus vernus</em>) along the path.</p> A spectacular show awaits visitors in the far southwest corner of the Rock Alpine Garden along the stucco wall at the boundary with the neighbors. Here a beautiful display of Helleborus</em>, Corydalis</em>, wind flowers (Anemone</em>), bloodroot (Sanguinaria</em>) and violets (Viola</em> odorata</em>) create a tapestry of color in April. Many woodland plants are programmed like alpines to bloom during a short season. Unlike plants high on top of a mountain which are delayed until warm temperatures melt the snow, woodland plants bloom in early spring before the trees above leaf out and block out the sun. This means the woodland areas are at their best in April as well.</p> I hope you can make it to the Rock Alpine Garden in the month of April. While you are at the Gardens make sure and check out the alpine section of the Mordecai Children’s Garden</a> — it should be in prime color as well.</p>
Visitors walking in the Gates Montane Garden may notice something strange through late spring: black velvet bags on the tips of one tree near the Cheesman Park gate. It is not trash or a new art installation — the Gardens' horticulture staff is attempting to propagate the tree, a bigtooth maple, which has recently come under attack by our local squirrel population.</p> The bigtooth maple Acer grandidentatum</em> is a Colorado native that thrives in dry conditions and tolerates heavy soils much better than other maple species. It’s a smaller tree that can have either a tree-like or shrub-like form and has excellent fall color.</p> This specific tree was collected near Logan, Utah because of its good fall color and more tree-like form. In an effort to save the genetics of this tree from marauding squirrels, we are using propagation techniques pioneered by researchers at Utah State University. This species is usually very hard to propagate by cuttings, but by placing dark bags over the stems, the tree is forced to grow in darkness — a process called etiolation. Cuttings taken from this etiolated growth root much easier than cuttings taken from stems that grew in full sunlight. The bags will be removed after the tree begins growing in late April or May.</p> If successful, the propagated clones of this tree will be planted in other locations at the Gardens. Perfecting vegetative propagation of bigtooth maple will allow us to provide trees with a predictable habit and fall color, since trees grown from seed take a long time to grow and can be very variable in their appearance.</p> If this experiment is successful we hope to propagate more bigtooth maples in the future to make them available at the Grown at the Gardens division of the Spring Plant Sale.</p>
Be sure to stroll the paths of the Boettcher Memorial Tropical Conservatory where you can enjoy plenty of non-orchid tropical blossoms. Although we are often focused on beautiful flowers, tropical foliage can have its own special appeal. While stopping to “smell the roses,” why not give a little attention to plant foliage too.</p> One of the first plants you might notice as you enter the Tropical Conservatory from our main lobby area is Codiaeum variegatum </em>var. pictum,</em> also known as croton. Crotons are native to southern India and are a great houseplant for high-light areas. There are many crotons on display throughout the Tropical Conservatory with varying leaf forms and color combinations, however the plant by the front entrance may be my favorite. It was added to the Gardens' collections in February of 1965 and was a gift to the Gardens from the Missouri Botanical Garden for inclusion in the first plant displays in our Tropical Conservatory when it opened in 1966.</p> As you make your way deeper into the Tropical Conservatory you will notice several banana plants. The most impressive may be Musa itinerans </em>var. guandongensis, </em>a banana native to the Guandong province of southeast China. While the size of the leaves and the height of the growths are impressive, perhaps the most dramatic feature of this banana is its aggressive suckering growth habit. Be sure to look at the base of the plant and you’ll see why we planted it in a contained area.</p> Another plant with striking foliage is Calathea lancifolia</em>. This plant belongs to the family Marantaceae, or the prayer plant family. This common name was given because many species in this plant family have leaves that fold upward in the evening hours as if folded in prayer. This particular species is from Brazil and has spectacular foliage. Be sure to look for other Calathea</em> throughout the Tropical Conservatory.</p> In the southwest corner of the Tropical Conservatory you will find a ficus tree with amazing foliage. Ficus aspera </em>is native to Vanuatu and is easily recognized by its amazing variegation – even the fruit is variegated. Take a moment to appreciate the tree’s contorted trunk form as well.</p> As you enter Marnie’s Pavilion at the west end of the Tropical Conservatory, you will see another unusual ficus – Ficus americana</em>. This large tree may look like the more familiar Ficus benjamina</em>, but as the name implies, F. americana</em> is native to Central and South America while F. benjamina </em>is native to tropical Asia and northern Australia. Did you know that ficus flowers are all pollinated by wasps?</p> Notice the beautiful complimentary foliage colors as well as the orchid blossoms in the Orangery. See hundreds of exotic blooms at the Orchid Showcase</a> in the Orangery through February 20 – included with admission to the Gardens. The Showcase is open 9 a.m. – 5 p.m. daily. Don’t forget to look through the glass to see the more unusual orchid blooms on display in our collection greenhouses.</p> We hope you enjoy your visit!</p>
For most horticulturists, winter is the time to prepare new planting schemes and dream of greener pastures. Of course, you could be fortunate enough to be able to work in a conservatory, where you are surrounded by colorful flowers and foliage year round, even in the dead of winter. The Boettcher Memorial Tropical Conservatory is home to a large portion of Denver Botanic Gardens’ Tropical Collection and educates guests about one of the most ecologically diverse climate on earth.</p> An important plant family housed in the Tropical Conservatory is the palm family (Arecaceae). Palms are prevalently located in tropical regions of the world and are used as a source of food, clothing, and building material. All palms highlighted in this tour are marked and mapped on the Gardens Navigator website</a>.</p> </p> Kerriodoxa elegans</em></strong> – When you first enter the Tropical Conservatory, you are greeted with the most elegant palm Denver Botanic Gardens has. Kerriodoxa elegans</em> stands out despite being an understory palm because it grows large, fan-shaped fronds to catch as much sunlight as it can beneath larger trees in its natural habitat. What makes the foliage also eye-catching is the coloration; the top side of the leaf is a glossy green, underside is a pale white, and the petiole (stem of the leaf) is a dark purple. As you walk by, you’ll also be able to notice the inflorescence and seeds at the base of the plant.</p> </p> Dypsis lastelliana </em></strong>‘Darianii’</strong> – In the bed next to the Kerriodoxa elegans</em>, you’ll find a palm with fuzzy copper colored palm sheaths (the base of a palm frond petiole). As the plant continues to grow, the sheaths of older leaves can remain on the plant longer than the leaf itself, so the upper trunk of the palm has both great color and an interesting texture.</p> </p> Aiphanes horrida</em></strong> (</em>syn. A. aculeata)</em> – As you walk up the south side path you’ll notice a terrifying stalk covered in grotesque spines. Obviously, this is not a pleasant plant to work with, having spines everywhere including the leaves. To make matters worse, this palm self-seeds constantly. I consider this plant as a “highlight” because unlike the far more pleasant palms we have, this one allows for plenty of character building as you weed these spiny seedlings in the nearby beds.</p> </p> Chamaedorea metallica</em></strong> – As you continue down the south path, you’ll find one of my favorite palms before the stairway to the treehouse. This palm is gaining popularity as a houseplant because of it being a compact size plant that thrives in shade. The fishtail-shaped leaves are in a beautiful grey/blue color. Along the trunks are adventitious roots which allows us to cut and replant a plant if it gets too top-heavy.</p> </p> Coccothrinax crinata</em></strong> – You’ll find this bizarre palm in the southwest corner of the Tropical Conservatory. Its leaves and inflorescence aren’t anything that stands out. The real interesting characteristic is its woolly fibers all along the trunk. I don’t like to use plant common names, but the name “old man palm” is very appropriate to use.</p> </p> Areca vestiaria</em></strong> – You’ll find this palm on the north side of the Tropical Conservatory, or if you head up the treehouse, you’ll be at the perfect height to admire this standout plant. It has bright red fruit and a colorful crownshaft, adding some color to the canopy level of our Tropical Conservatory.</p> </p> Carludovica palmata</em></strong> – You’ll find this along the Tropical Conservatory north path, next to the Areca vestiaria. </em>This palm was part of Denver Botanic Garden’s Tropical Collection when the conservatory first opened in 1966. The leaves of the plant are used to make Panama hats.</p> </p> Zombia antillarum</em></strong> – located in the northwest corner, Zombia antillarum</em> is an endangered palm native to Hispaniola. This palm has spines arranged in an interesting manner. Unlike the spiny Aiphanes horrida</em>, the spines on Zombia </em>palms are only found on the trunk.</p> </p> Ravenala madagascariensis</em></strong> – Despite having the common name of “traveler’s palm,” Ravenala madagascariensis</em> is not a palm. It is actually in the bird-of-paradise family (Strelitziaceae). It’s a beautiful plant with 5’ broad leaf blades in a fan arrangement and white bird-of-paradise flowers. It’s a good lesson to not be reliant on common names, as they easily mislead people into wrongly identifying plants.</p>
Where do plants go when they die at the Gardens? Most, as you might expect, go to the compost pile, but a select few get a lucky break: a chance to be displayed again.</p> Each fall, armfuls of cuttings are hung and dried in our tool room for winter arrangements. These are what we call “everlasting plants,” varieties that stay crisp and colorful long “since sunshine fed them, or the showers,” as English author Walter Thornbury so sweetly put it.</p> Only the most resilient plant stems, flowers and seed pods make the cut. They not only have to hold their form or color for months after they’re pulled, but they have to take a good battering from the weather.</p> This year, we take you on a tour of more than two dozen winter outdoor containers, from classic elegant designs of cut evergreens, grasses and dried flowers to quirky new displays that depart from the traditional bouquet.</p> We start at the parking garage by the York Street pedestrian crossway, where grasses take center billing in two lively bouquets that move at the touch of breeze. Plumes of pampas grass (Cortaderia selloana</em>) tower above the rose-pink blades of little bluestem grass (Schizachyrium scoparium</em>) and wheat-like flowers of Karl Foerster feather reed grass (Calamagrostis</em> x acutiflora </em>‘Karl Foerster’). Lacy umbels of Joe Pye weed (Eutrochium purpureum</em>) and balls of dried hydrangea Annabelle (Hydrangea arborescens</em>) add a playful contrast, while slender stems of Japanese rose (Kerria japonica</em>) give the bouquet a zing of spring green.</p> </p> Crossing York to the front of the Bonfils-Stanton Visitor Center, red twig dogwood shrubs (Cornus sericea</em>) frame the front doors, their limbs angled skyward in grand gestures of hello. Among these living bushes are some of the largest and toughest flowers you can dry, each held high on stems of wood and wire -- giant sea holly (Eryngium giganteum</em>) sprayed white, hydrangea Annabelle tinted chartreuse, moon carrot (Seseli gummiferum</em>) colored red and -- the Cinderella of the bunch -- teasel (Dipsacus</em>), sprayed green.</p> </p> Passing through the Visitor Center and into the Welcome Garden, two large branches arc around the video screen, their bark lightly glazed in glitter. Dozens of ornaments made almost entirely from plants dangle from nooks in the branches, while bundles of dried flowers define tips of the branches with punches of red, green and white. Do you recognize the painted pods of evening primrose (Oenothera macrocarpa</em>)? Or the maple seeds wired into flowers? What about the seed shell from false indigo (Baptisia australis</em>) that’s become the face of a dancing sprite?</p> </p> Turn to your left and you’ll find two garden trellises at the bottom of the stairs that long to be holiday trees. Each is entwined in false spirea (Sorbaria sorbifolia</em>) stems and adorned with reddened stonecrop (Sedum</em> sp.), white statice (Limonium sinuatum</em>) and the dried fruits of teasel sprayed chartreuse. Pine cone ornaments and miniature wreaths of dogwood hang from horizontal wires and cuttings from spruce branches add softness to the display.</p> </p> Next, take a stroll down O’Fallon Perennial Walk to the Romantic Gardens, where the tradition of outdoor arrangements at the Gardens was born. Here, more than a dozen urns arranged by Denver Botanic Gardens Guild volunteers are scattered in beds and gazebos. Evergreen boughs, dogwood stems, hydrangea blossoms and branches of rose hips combine with classic elegance. Scattered among them are wands of pussy willow, ripe with catkins - a whimsical nod to spring - and dried cuttings of dusty miller (Jacobaea</em>), that lend a frosty contrast to deep green needles. Dried flowers, from statice (Limonium</em>) to yarrow (Achillea</em>), punctuate the bouquets with color.</p> </p> Straight ahead in the Ellipse, oversized pine cones and diminutive plants transform urns at the entry into magical little gardens. The cones sit on their ends at playful angles, while red pansies shimmer in the sunlight. Boughs of juniper, speckled with icy-blue berries, and Hens and Chicks (Sempervivum</em>) peek out at the edges. Nearby, perched on a stone railing in front of Waring House, are four more adorable urns. Each contains a single large pine cone nesting among holly grape (Mahonia haematocarpa</em>), rose-colored barberry (Berberis</em>) and yellow-green arborvitae (Thuja occidentalis</em>).</p> </p> Taking a turn west, head down the path past the Herb Garden to the Fountain Beds and Ornamental Grasses Garden, where two little Colorado spruce (Picea pungens</em>) pay tribute to my favorite Christmas book, Mr. Willowby’s Christmas Tree</em>, about a tree cut down to its tiniest and trimmed by woodland creatures. Each is wrapped in a garland of red strawflowers (Xerochrysum bracteatum</em>) and topped with a large seed head of white-washed dill (Anethum graveolens</em>). Bells in acorn shells add jingle, while bleached pine cones lend a frosty touch and sprigs of hawthorn berries, a bit of merriment. This one also includes umbels of moon carrot posing as giant snowflakes.</p> </p>
