I am in the very fortunate position that I can translate my work at Denver Botanic Gardens into a doctorate in integrative and systems biology from the University of Colorado, Denver. I’m gaining new tools and insight for the applied plant conservation work I hope to continue far into the future. For my dissertation, I am focusing on estimating extinction risk of small populations over time and space. Even if a population is likely to go extinct in the foreseeable future, that might not mean the loss of an entire species. The Gardens actively collects seed of rare and threatened plants to use in case of catastrophic loss. I will use extinction risk analyses to determine effective and safe levels of seed collection for ex-situ conservation and for management recommendations. </p> Currently, my focus is on the time scale of rare plant conservation planning. In small populations, long-term persistence can be greatly impacted by stochasticity, which is variation in demography (random variation in survival and reproduction among individuals within a population) and response to a variable environment. This random variation, or stochasticity, increases extinction risk in smaller populations because of the increased chance that all individuals die prematurely. Imagine you’re flipping a coin; you’d think you’d get half heads and half tails. However, when the number of flips is small, there’s a much greater chance that you’ll get all tails. It’s not until you’ve flipped that coin for a while that you’ll land on a nice percentage of 50 percent heads and 50 percent tails. Larger populations are buffered from this stochasticity. </p> Because of the Gardens’ long-term support of research and conservation, I have large datasets on rare plant populations, including 26 years of annual survival, growth and reproduction rates for Astraglaus microcymbus</em> across six populations. Typical plant studies have as few as three years of data. The common practice is to assume we have enough data of population changes over time to measure the long-term population growth rate. We can then simulate a population through time by drawing growth and reproductive rates from good or bad years to estimate the impact of a variable environment. In this way, we can test how a seemingly stable population might still go extinct depending on the climate. </p> I have primarily studied long-lived, perennial species. In general, plants can either put more energy towards reproduction or towards survival and this trade off determines whether survival or reproduction is most important in changing the population growth rate. I would not expect that all types of plants would respond in a similar fashion to stochasticity. A fast growing annual that puts most of its effort into reproduction will be impacted differently and across a different time frame than a tree that produces a few seeds every year but does so for centuries.</p> Selecting the time horizon over which to estimate risk is an arbitrary decision. The number of years to project extinction risk into the future needs to be long enough to detect extinctions but not so long that uncertainty overwhelms assumptions about population dynamics. A short time frame for a tree will be a longer time frame for an annual. In the first chapter of my dissertation, I am testing which life history traits may predispose a species to extinction in a variable environment and how risk changes over time. </p> I will apply the findings of this project to applied conservation work at Denver Botanic Gardens. My studies are leading me to new questions about what threatens rare plant populations and methods to test conservation actions. It’s hard work but well worth it. </p>
Autumn is in the air! Fall marks a transition period in our gardens when most perennials, trees and shrubs enter dormancy for the winter, with flower shows giving way to textural and skeletal plant arrangements. Among gardeners, there is often the urge to tidy up after the first frost by immediately cutting back perennials and removing plant debris, but this can be counterproductive to both the aesthetic and ecological value of your garden. Here are a few tips to maximize the ecological utility of your garden this winter while maintaining a beautiful yard.</p> Leave as much standing plant material as possible. </h4> Many species of invertebrates, including beneficial insects and pollinators, use plant stems to nest or overwinter. By removing standing plant material from our gardens in the fall, we don’t allow these species to complete their life cycles. Birds and mammals also rely on upright dried plant material for food or shelter. </p> </picture> </div> </div> </article> Liatris punctata</em></p> In the spring once temperatures have warmed, cut back grasses and flower stems. Even better, cut back flower stalks at varying heights leaving some vertical stems in place as this helps native bees and other insects emerge from their winter slumber. </p> There is an aesthetic upshot as well; dormant plants in the winter are beautiful and allow you to see contrasting botanical shapes and forms in stark relief. Ornamental grasses in particular juxtapose beautifully with bold seed heads like Echinacea </em>or stiff upright forms of Liatris </em>and Silphium</em>. Of course, some plants hold up better than others in dormancy so consider cutting back unsightly soft plant material while leaving more rigid plants. You might be surprised how beautiful your garden is in the low, slanted light of autumn and winter. </p> </picture> </div> </div> </article> Dormant grasses catching light.</p> Allow some leaves, stems and other organic material to remain on the ground. </h4> This additional habitat will be appreciated by a wide array of organisms. For example, nearly three quarters of Colorado’s native bee species nest underground, so a covering of plant litter can help protect their nests over the winter and in the early spring when they become active. Allowing plant material to decompose in place can also improve soil health and provide nutrients to your plants, but keep in mind that this will depend on the type of garden that you have; xeric or dryland gardens may resent too much organic matter while more traditional perennial or shade gardens will appreciate the additional detritus. Vegetable gardens are an exception where it’s best to remove as much plant debris from your crops as possible to mitigate pressure from pests and pathogens.</p> </picture> </div> </div> </article> Schizachyrium scoparium</em></p> Start a home compost pile with your yard waste rather than throwing in it the trash. </h4> Alternatively, Denver residents can obtain free paper lawn bags and drop off leaves at designated sites this fall. In the spring, pick up discounted compost made from community collections (you can find details at Denver.gov</a> ). For a fee, you can also sign up for weekly compost collection if you live in the city of Denver. </p> Any of these options help to keep organic material out of landfills. Organic matter, including food scraps and yard waste, is the single largest input to landfills in the United States and substantially contributes to greenhouse gas emissions, especially methane. Composting organic material or sending it to designated compost facilities can drastically reduce your environmental impact while providing a useful garden resource. </p> </p> This article first appeared in the November issue of Life on Capitol Hill. Photos by Michael Guidi.</em> </p>
Welcome back, my fellow goblins and ghouls! Are you enjoying your Halloween week? As promised, we who work in the vault would like to share more strange creatures as documented by one of the Gardens’ founders, George Kelly.</p> Before we knock on the vault’s door to say, “Trick or Treat!”, let’s first explore the background of George Kelly, the photographer of our featured creatures. This esteemed horticulturist, conservationist, author, founder and photographer was born in Scotch Ridge, Ohio, May 8, 1894. Encouraged by his mother, he learned to love nature at an early age and even sought to become a forest ranger when he was in grade school. George was the first editor of the “Green Thumb” newsletter, published by the Colorado Forestry and Horticulture Association. Additionally, as founder of the Colorado Junior Mountain Club, he led youths on 66 climbs, many of them over 14,000 feet. After he passed away in Cortez, Colorado, August 10, 1991, the Denver Post mourned his departure, and called him the “Father of Rocky Mountain horticulture.”</p> In 1951, the same year he helped found Denver Botanic Gardens and photographed the strange creatures you are about to behold, George published “Rocky Mountain Horticulture is Different,” which was later republished as “Good Gardens for the Sunshine States,” which became the go-to guide among Colorado gardeners. George was a horticultural lecturer and broadcaster on radio stations KFEL, KLZ, KOA, KVOD, and published horticultural columns such as “Under Colorado Skies” in the Rocky Mountain News as well as “Peaks and Patios” in the Denver Post.</p> We hope that Kelly’s life and love of nature inspires you to view nature differently. Below, you will find Kelly’s Periscope Bird, Face with Eye, Horse Skull </em>and our personal favorite, the Flesh Eating Brontosaurus</em>. Following these is a portrait of George sketched in 1983. With that, we would like to close with two poems from his book, “The Things I Prize: Fun, Fantasy, and Filosophy,” dedicated to a couple of the strange creatures you will find below. </p> Happy Halloween from everyone in the vault!</p> “The Periscope bird was also called the Snooper. She can look around walls and trees Or can see over tall monsters Or far out over the seas. She may use her special talents To listen on party lines Or hang over the backyard fence Looking for things not on signs.” (p.100)</p> “The dinosaur did once abound, Had many forms and roamed around. Some bigger ones ate each other. Others ate whatever they found. But where is this great animal now, This great big lumbering beast? He couldn’t adapt as seasons changed, So now his kind have ceased.” (p.71) </p> This article was contributed by James Grau, an intern with the Exhibitions, Art & Learning Engagement Department. He is currently pursuing an MA in art history & museum studies at the University of Denver.</em></p>
People often think that when you’re a botanist, your favorite time of the year must be summer. Well, I do love summer, but fall is actually my favorite season. Why? Because I can finally relax! Summer is a non-stop whirl of field work to collect plant specimens – the ultimate purpose of which is to increase our knowledge of biodiversity in Colorado. This summer was a particularly great one for making collections – the flowers were so plentiful!</p> Field work began with a trip to the southeastern plains. We sampled from limestone breaks on land owned by the Southern Plains Lands Trust (SPLT) and were even invited to join the land manager as he fed herds of bison and Texas longhorns. You just never know what will happen in the field!</p> I then joined an expedition to scout a rare plant for future seed collecting. I could not believe how green and lush the foothills were – flowers everywhere! The summer’s most intensive collection project began in June – a floristic inventory of Axton Mountain Ranch, soon to be the newest Denver Mountain Park. Every week, our team – me, the lead collector, and two high school interns – explored the property, documenting the floral diversity. Again, I could not believe the shear abundance of flowers! Just spectacular.</p> My next stop of the summer is always one of my favorites – the Crested Butte Wildflower Festival. I lead hikes for the festival, serving as a scientific expert while connecting people with plants. The flowers in the Gothic Valley were amazing this year as well – particularly corn husk lily (Veratrum californicum</em>) and five-nerved little sunflower (Helianthella quinquenervis</em>) presented especially incredible displays. </p> In August, I traveled to the La Sal Mountains of Utah. My research on thistles (Cirsium</em>) revealed a new species of thistle endemic to these mountains, and so I went to make type collections. These types will serve as the reference for this newly described species.</p> The summer ended with another expedition to the southeastern plains, but this time to the Comanche National Grasslands. We were targeting grasses, particularly a potentially new grass record for Colorado. During this trip, we also experienced the magic of Mentzelias</em>. Mentzelias</em>, or stickleaves, open their flowers in the evening. We arrived at Mentzelia decapetala</em> as the sun was setting, just in time to see the flowers visited by hummingbird hawk-moths. The whole event took about 15 minutes and was indeed magical. All in all it was a busy, productive and fun summer in the field. Now to process all those collections for deposit into the Kathryn Kalmbach Herbarium of Vascular Plants</a>. </p>
Since Japanese beetles came into to our garden life, it has been almost impossible to keep my grapevines presentable in Le Potager garden; the beetles skeletonize almost all the leaves over summer. It looks terrible on the pergola in the middle of the garden as the brown grapevine contrasts with the rest of the lush, green space. I decided to matchmake this sad grapevine with birdhouse gourds to cover up their destroyed leaves. It worked perfectly! The gourd climbed up on the grapevine happily and produced aromatic white flowers during summer evenings that later became the humorously shaped fruits perfect for craft projects (now I must think whether I should make birdhouses or flasks).</p> Growing birdhouse gourds is very easy. You can ‘direct sow’ their seed into the fertile garden bed in late May (after the last frost date in your area) or start a few weeks earlier indoors then transplant the seedlings. The gourd vine likes a sunny location with well-drained, fertile soil. Also, keep soil moist and don’t let it dry out, just like in a traditional vegetable garden.</p> The birdhouse gourd is a vigorous flowering annual vine, which climbs onto a garden structure (such as a pergola) easily with its tendrils. You can also plant them on a compost heap to cover it up (make sure your gourd fruit does not touch the ground directly to prevent rot). The plants produce both male and female white flowers on the same vine. You can easily identify the female flower as the bottom of the flower is swollen into the shape of a small gourd. Once your seedlings start taking off, make sure to let them grow until the main vine can reach to the structure (or your desirable height) where you would like your gourd to climb, then prune it to develop the lateral branches for encouraging it to produce more female flowers.</p> Birdhouse gourd, Lagenaria siceraria</em>, is a hard-shelled gourd, a type of tropical squash (cucumber family, Cucurbitaceae</em>) native to northern Africa. The hard-shelled gourd was cultivated by people 10,000 years ago. It spread all over the world because it is easy to grow and produces fruits that were used as bottles to carry water, storage for foods, floating devices, musical instruments, garments and more.</p> There are many ways to dry the gourds, but the easiest way is to keep the gourd fruits on the vine until the first freeze (the leaves and vine are brown), then harvest and store them in a cold, dark and dry storage area such as garage or basement. Make sure to check them occasionally and turn each gourd to prevent molding. After the gourds are dried, you can drill a small hole to make your birdhouse.</p>
In 2020, 38.3 million Americans lacked the resources necessary to acquire enough food to meet their needs. At the same time, upwards of 40 percent of all food produced – equivalent to nearly 160 billion pounds – was wasted. It’s difficult to fathom that in a country where nearly half of our food is simply thrown away, anyone would lack access to a meal, yet this reality defines the state of our current food system in the United States.</p> The USDA defines food insecurity as, “A household-level economic and social condition of limited or uncertain access to adequate food.” While hunger is an obvious consequence, increased risk of birth defects, cognitive issues, depression and anemia are just a handful of myriad issues that can arise directly from living in a food insecure state. It’s clear that the health of our neighbors and communities as a whole relies heavily on our ability to provide access to healthy and responsibly-grown food for all.</p> Reaching food deserts</h4> The question I ask myself every growing season is how can I effectively utilize the tenets of regenerative agriculture to create a more just and equitable food system; one where nutritious food is accessible to all people and grown in a way that reverses the deleterious effects of climate change? </p> At the urban farms located in the Denver communities of Mariposa and Sun Valley, we grow organic produce and distribute it to the community free of charge. These communities exist within food deserts; locations where healthy, unprocessed food is scarce and grocery stores are non-existent. This lack of healthy food access is a major contributing factor that leads to food insecure communities. By growing and distributing nutritious, organic and sustainably produced food to a community that would otherwise go without, we are working toward a future that emphasizes equity over exclusion, and environmental stewardship over exploitation. With that said, the work that we do must be subject to continuous critical evaluation to ensure that we continue to serve the community in the most effective and responsible ways possible.</p> </picture> </div> </div> </article> Taking action</h4> While this vision of a regenerative food system may sound like a utopian pipedream, it’s actually more of a necessity than an ideal. The United Nations (UN) Department of Economic and Social Affairs (DESA) confirms that utilizing agroecological methods of food production (i.e., regenerative and sustainable agriculture) is paramount in winning the fight against hunger and food insecurity. In fact, of the 17 Sustainable Development Goals (SDGs) set forth by the UN, goal two seeks to end hunger, achieve food security and improved nutrition, and promote sustainable agriculture. The inclusion of eradicating food insecurity in the UN SDGs denotes just how imperative it is to address this issue on a global scale with the utmost urgency.</p> Hunger and food insecurity are complex issues that are inextricably linked to agricultural production and distribution. While our current food system exacerbates these issues, we have the ability to reshape our shared food system into one that not only ends food insecurity, but one that reverses climate change as well. Achieving this feat will require a deep understanding and reexamination of our economic, social and political systems at large. There’s no doubt that deep systems change cannot come about without major action taken by governments and public and private institutions alike. </p> Want to help reshape our food system?</h4> Learn more about hunger and food insecurity and engage with your elected representatives.</p> Hunger Free Colorado</a></li> Denver Sustainable Food Policy Council</a></li> </ul> Support local organizations working toward building a more just and equitable food system either by volunteering or donating.</p> Food Bank of the Rockies</a></li> Denver Urban Gardens</a></li> Denver Botanic Gardens Urban Food Initiatives</a></li> </ul> Speak with people in your community about food insecurity. Building connections and understanding the specific needs of your neighbors will help you better recognize what you can do to help.</p> Do what you can, when you can, where you can.</p>
Summer bulbs excite me the way that plastic eggs from a giant rabbit vending machine did when I was a child. I get a thrill from anticipating what’s inside— no matter how many times I’ve seen it before. </p> Perhaps that’s why I treasure saving bulbs from year to year, knowing that, come summer, I’ll relive the wonder of seeing them periscope out of the ground and unfurl their blooms in shapes as varied as funnels and pompoms.</p> </picture> </div> </div> </article> 'Gladiolus' Jester in the beds by the Fountain Beds.</p> Of course, not all bulbs need to be saved indoors. Those that are hardy in our climate happily winter over in the ground. The bulbs that have to be stored indoors originate from tropical climes and they would literally turn to mush if left outside in winter.</p> The list of tender bulbs is long and varied — from Mexican shellflower to pineapple lily. But not all tender bulbs are easy to store, and since we all have limits on time and space, it’s good to narrow the list to a few favorites that aren’t tricky to save.</p> Four bulbs I store without fail are dahlia tubers, canna rhizomes, gladiolus corms and giant chincherinchee bulbs. These are some of the most thrilling bulbs to see in displays and some of the easiest to store.</p> </picture> </div> </div> </article> Dahlia 'Linda's Baby'</p> Dahlias are the divas of the summer bulbs and have a reputation for being difficult to store, but in truth they aren’t as finicky as you might expect. If you follow these guidelines, you’re sure to have more than enough tubers come spring. </p> Wait for two hard frosts before you dig out the tubers. After the first frost blackens leaves, cut the stems back to 6 inches. Then after the next freeze, carefully dig out tubers with a shovel.</li> Once lifted, rinse off your tuber clumps and let them dry for 24 hours. (But never on a concrete surface as this will pull moisture out of them too quickly.) </li> Then clip off any hairlike roots and cut back stems to an inch. </li> At this point you can separate tubers or store whole clumps in large plastic bins filled with wood shavings, taking care not to let clumps touch.</li> Store the bins in a dark place that stays at 40-50 degrees F and lay lids on top of bins but don’t seal them.</li> Check on the tubers monthly. Discard any tubers that become moldy. If mold occurs, replace the wood shavings.</li> </ul> The last three bulbs are the easiest to store.</strong></p> Before digging up canna, gladiolus or giant chincherinchee in fall, let the foliage blacken.</li> Ease the bulbs out with a shovel, rinse off the dirt and cut back canna foliage to 6 inches, and gladiolus and chincherinchee foliage to 1-2 inches.</li> Lay out the bulbs to dry for 2-3 weeks, then remove the shriveled mother corms from gladiolus.</li> Store gladiolus and chincherinchee bulbs in open crates or mesh bags and canna in plastic bins between wood shavings. All three should be stored in the same conditions as the dahlias.</p> </li> </ul> </picture> </div> </div> </article> Clump of dahlia tubers after it was dug up and rinsed. </p> This article appears in the October 2021 issue of Life on Capitol Hill.</em></p>
