Have you heard about the Rocky Mountain Gardening Certificate Core Series? This is a comprehensive study of specific gardening practices for our unique Front Range region offered by the Gardens. Classes include soil preparation techniques, horticulture and basic plant science. It can be completed as a cohort in five months or by taking classes individually over a two-year period.</p> I was curious about what inspires people to take the Rocky Mountain Gardening certificate program, so I asked the latest cohort. Each had distinct reasons but similar passions and goals for investing the time and energy in completing the certificate in five months. The program is deeply rooted in fulfilling our mission to connect people with plants and promote the Gardens’ values. Recipients had this to say:</p> Diversity:</strong> “Weeding is a waste of time! I wanted to create a model low-maintenance urban garden with native trees and xeriscape and share the possibilities with neighbors and friends.”</li> Relevance:</strong> “I’ve always been amazed by the beautiful power of trees and never realized it could become a career path to nurture trees. Even though I’m a busy mom of four and help with the family business, the certificate course helped me realize a career goal. The instructors were great at answering questions.”</li> Sustainability:</strong> “The certificate course gave me a great toolbelt for working with native plants. It stimulated my interest in regenerative gardening practices.</li> Transformation:</strong> “I learned so much about the importance of soil and organic composting. I have a kitchen garden because cooking is my passion. I gained knowledge and confidence to figure out what has gone wrong and not give up with skills learned in the diagnosing problems classes.”</li> Stewardship:</strong> “I wanted to change my ‘do nothing but create water bills’ lawn and create a home space that showed stewardship of Earth values. I felt empowered to have discussions with my HOA and with yard experts after earning my certificate.”</li> And, with a vision for professional development:</strong> “I work with city residents who want to find cost-effective methods to improve their land. Now I feel confident that I can address their questions with reliable information and resources. People want to build ecosystems through smart gardening and now I know how to help them.”</li> </ul> The Rocky Mountain Gardening Certificate’s importance goes beyond knowledge and skills. Even though participants have individual goals, they are connected by a passion for the environment by wanting to support sustainable ecosystems and create healthy habitats. Find out more about the certificate</a>. </p>
When you stop to smell the flowers, you’ll notice that many of them do not quite smell the same.</p> The Science Behind Floral Scents</h4> There are biochemical reasons behind distinct scents. To discover them, we analyze the associated volatile organic compounds (VOCs) that are produced by plants. These combinations of molecules aid in attracting pollinators, deterring herbivores, preventing microorganism colonization and even enabling communication with other plants. Volatile organic compound composition can play a pivotal role in gene flow and can vary among populations due to differing selective pressures from local insect communities.</p> Polemonium </em>(Polemoniaceae) is distributed primarily throughout the western United States and Canada, with few species found in South America, Asia and Europe. Within the genus, there is a group referred to as the Polemonium viscosum</em> complex, consisting of three closely related, high elevation species: P. viscosum</em> Nutt., P. confertum</em> A. Gray and P. brandegeei</em> Greene.</p> Untangling a Taxonomic Mystery</h4> Polemonium viscosum</em> is usually described as having a stronger "skunky" odor, while P. confertum</em> is noted for its sweeter aromatics. The unique floral aromas make the complex ideal for investigating scent variation in alpine environments. However, taxonomy within this group is controversial and disagreement exists on the recognition of P. confertum</em> apart from P. viscosum</em>. This has serious implications on the insights into the role of floral scent divergence and species boundaries.</p> To explore the taxonomic confusion and floral scent profiles of the species within this genus, I have dedicated the last two years to collecting as much data as I can on them. I spent the summers of 2024 and 2025 collecting tissue and scent samples of the species throughout the Southern Rockies of Colorado and New Mexico.</p> Exploring Speciation in Alpine Wildflowers</h4> By integrating floral scent analysis with statistics of genetic relatedness, this project aims to resolve species boundaries while also characterizing floral scent variation within the Polemonium viscosum</em> complex. These wildflowers present a unique opportunity to explore floral scent variation and its role in speciation, with implications for conserving alpine plants.</p> Is speciation occurring in sympatry driven by divergence in floral scent profiles? Or is there a single species exhibiting two distinct floral scent profiles to optimize ecological opportunities in an alpine environment with limited pollination potential?</p> This article was contributed by graduate student Ash Kerber</strong>.</em> </p>
Denver is located in a steppe ecosystem that is characterized by extremes: extreme cold, heat, drought, hail and wind. To be a plant that survives this environment is to be resilient, to bounce back after adversity and to adapt. We know plants can survive these conditions because we are surrounded by them when we step into our natural ecosystems in the plains and foothills, and increasingly when we step outside our front doors into our neighborhoods and parks. Plants have been surviving—and thriving—in steppe ecosystems for millennia, evolving in conditions like long droughts, harsh sunlight and strong winds to have adaptations such as deep roots, protective hairs and fine leaf textures. </p> Resilience Is Beautiful</h4> Resilient gardens are beautiful gardens, not just in their resilience, but in their aesthetics. With adaptation comes diversity in form, texture, color and bloom timing—key ingredients of designing an attractive garden. The Roads Water-Smart Garden and Nexus Garden exemplify how low-water, adapted plants from Colorado and similar steppe environments can be combined to create focal points, contrast, patterns, ongoing blooms and interesting winter structure that give year-round appeal alongside decades-long resilience in our Denver climate. </p> The Perfect Time to Plant</h4> You may be on the fence about planting a new garden or integrating water-smart plants. Now is an excellent time to invest in resilient plants adapted to harsh climate conditions. As you’ve likely learned, Denver Water has implemented Stage 1 drought restrictions for summer. In the coming decades, temperatures in Denver are expected to continue to increase while water availability becomes more sporadic; droughts are not new for Denver and are likely to become more frequent and severe. Embracing resilient plants in our gardens and landscapes prepares us for this future. Once established, resilient plants can withstand drought and extreme heat, reducing our water demands and building our own resilience to future watering restrictions.</p> Explore the Gardens’ water stewardship initiatives</a> for inspiration and shop Spring Plant Sale May 8 and 9</a> to add water-smart plants to your landscape.</p> This article was contributed by Manager of Sustainable Landscape Services Marissa Sterrett </strong>and volunteer Jaclyn Kachelmeyer</strong>.</em> </p>
Let’s celebrate Earth Day and our Front Range biodiversity by participating in the City Nature Challenge</a>! This is a yearly event for folks in cities all over the world to observe and document biodiversity in their own backyards. Any living organism is fair game for observation – plants, mammals, birds, insects, fish – they all contribute to the City Nature Challenge. To participate, make observations of any organism on iNaturalist during the observation phase. This is followed by an identification phase—where you can join a community of nerdy naturalists to identify the species observed. Learn more and find local bioblitzes</a> near you.</p> CITY NATURE CHALLENGE 2026</strong>Observations: </strong>April 24 – April 27Upload and Identification Phase:</strong> April 28 – May 10</p> For 2025’s global challenge, there were 3.3 million observations of almost 74,000 species made by 103,000 people from over 62 countries around the world. This brings the total number of observations made during the past 10 years to almost 13 million! </p> Meanwhile, in the Denver-Boulder metro area, more than 9,714 observations were submitted by 764 people of 1,260 species. We nearly doubled our number of observations and observers compared to 2024 and we broke our previous record in 2020 of ~7,000. This year, our most observed species was Chokecherry (Prunus virginiana</em>). Fun species observed included a silver fox</a>, Abert’s squirrel</a>, prairie violet</a>, beaver</a>, black-crowned night heron</a>, little brown bat</a>, American mink</a>, elk</a>, moose</a>, northern harrier</a> and black bear</a>. We even had 145 research-grade observations of 26 species</a> that are listed as rare, endangered or threatened by NatureServe or the U.S. Fish and Wildlife Service (over twice as many as last year). </p> It’s easy to participate – your iNaturalist observations will automatically be added to the City Nature Challenge 2026: Colorado Front Range</a> project if they are made during the challenge event and occur in the Front Range (see above link for map of included areas). Additionally, all plant and fungal observations will automatically be added to the Denver EcoFlora Project</a>. </p>
Local legends abound surrounding the history of Cheesman Park as an unkept and crumbling cemetery that was later transformed into the recreational area it is today. Before its green fields were dotted with volleyball nets and slacklines, this park was City Cemetery, Denver’s first large cemetery, established in 1859. Originally intended to be a scenic Victorian cemetery like those seen in Boston, New York and parts of Europe, this vision was never realized. Pressure to use the area in a way that would better appease its burgeoning affluent neighbors in Capitol Hill ultimately led to its transformation into a park. </p> Easier said than done. Thousands of occupants already resided underground in City Cemetery. Undertaker E. P. McGovern was contracted to relocate remains to Riverside Cemetery several miles away in early 1893. Paid by the coffin, McGovern soon saw a way to exploit the wording of his contract and unearthed remains were split between multiple child-sized coffins which were then hauled across town. The city discovered what was going on, halted McGovern’s work entirely and required that all remains either be relocated at their survivors’ expense within 90 days or remain onsite. </p> Imperfect maps identifying locations of remains, fear of diseases that could be spread by unearthing remains, and the inability of individuals to pay relocation costs for loved ones prevented work from being completed in time for the park’s opening.</p> It is estimated that 2,000 to 3,000 human remains still reside under Cheesman Park. </p> Adjacent to City Cemetery was Mount Calvary Cemetery—where Denver Botanic Gardens now exists. Owned by the Catholic Archdiocese of Denver, this cemetery was better maintained than neighboring City Cemetery but fell into disuse after Mount Olivet Cemetery was established in Wheat Ridge and became the only consecrated Catholic cemetery in the area. The abandoned Mount Calvary was used primarily as a playground for adventurous children until it was finally deeded to the City of Denver in 1950. </p> The relocation of remains from Mount Calvary to Mount Olivet was more organized and expedient than the transition from City Cemetery to Cheesman Park had been, but not without issues. Occasionally remains would be missing from where they were marked on the cemetery’s records, while others would be found during construction and maintenance where no burial had been recorded. </p> Denver Botanic Gardens was first partially and then completely relocated from its original home in City Park to the former site of Mount Calvary in the late 1950s and early 1960s, with the Boettcher Memorial Tropical Conservatory being formally dedicated in January of 1966. </p> Although considered by some to be less haunted than our larger neighbor, the Gardens still has its share of ghost stories and reported hauntings. </p> To learn more about the hauntings and history of Denver Botanic Gardens and Cheesman Park, browse these books at Helen Fowler Library: </p> The Ghosts of Denver: Capitol Hill by Phil Goodstein </a>Written by local historian and walking tour guide Phil Goodstein, this volume covers much of the history of Capitol Hill and Cheesman Park neighborhoods, including the haunted history of the park and its surroundings. </li> Cemetery to Conservatory by Louisa Ward Arps </a>A publication of Denver Botanic Gardens, this work covers the transition from the cemetery to its current use in detail, spanning the period from 1859 to 1980. </li> The Dead Below by Richard Estep </a>Follow Colorado author Richard Estep and his ghost hunting crew as they explore Waring House at Denver Botanic Gardens in search of evidence of the supernatural. </li> </ul> This post was contributed by On Call Librarian Sean Grimes</strong>. </em></p>
Mushrooms can be poisonous. That is one of the first things we are taught as kids. Even though plants produce more detrimental toxins than mushrooms, society, rightly or wrongly, tends to teach the latter as being more dangerous. While attitudes toward mushrooms have been changing, the history around mushroom poisoning shows growth in understanding all the ways eating them can make people sick. </p> At Denver Botanic Gardens, Dr. Sam Mitchel</a> was perhaps the most central figure to expand mycology and knowledge of mushrooms of the Southern Rockies. He is not as well known for his role as a medical doctor and as a trained diagnostician. However, this dual perspective gave Dr. Mitchel the ability to merge his passion for mushrooms and medicine to produce an understanding of how they might poison people. </p> Along with other Denver-based doctors Drs. Barry Rumack and Manny Salzman, Dr. Mitchel coordinated efforts to understand and educate medical professionals about mushroom poisons in the 1970s. These efforts primarily took place in Colorado around the mid-70s when the Aspen Mushroom Conference became one of the first to train doctors from across the country. This conference gave doctors skills to ID mushrooms and diagnose mushroom poisonings, and included training on the variety of toxins that mushrooms can produce, how they affect the people who consumed them, and how doctors can treat their patients. </p> In general, there are seven poisoning “groups” that mushroom toxins can fall into: Cyclopeptide poisoning, Monomethyldrazine poisoning, Coprine poisoning, Muscarine poisoning, Ibotenic acid – Muscimol poisoning, Psiocybin-Psilocin poisoning and Gastrointestinal irritants. In 1977, Dr. Mitchel teamed up with the late celebrated mycologist Gary Lincoff to write “Toxic and Hallucinogenic Mushroom Poisoning: A Handbook for Physicians and Mushroom Hunters,” which details each of these poisonings and how to treat them.</p> Today these efforts to understand mushroom toxicology continue in Colorado. Dr. Rumack, with the assistance of Gardens volunteers Ed and Ikuko Lubow, continues to train doctors on identifying mushrooms and the poisons they produce. Nationally, the North American Mycological Association (NAMA) has an active Toxicology Committee that continues to offer aid and assistance in identifying toxic mushrooms and advising doctors and poison centers on how to diagnose poisonings.</p> Internationally, Dr. Mitchel’s work has reached across the Pacific to Borneo where medical professionals in Malaysia came together for a Mushroom Toxicology workshop in 2019. There the doctors learned about the mushroom poisonings above, as documented through the work done here in Colorado. </p>
Everyone’s life is marked with memories that stay with us forever. Some of my most cherished plant memories come from discovering the stunning world of cacti and succulent plants that are housed in the Cactus and Succulent House located in the Rock Alpine Garden. </p> I had the privilege of taking over this collection and replanting the display house during the summer of 2021. Now, after three years of care, the plants have really filled in and grown fantastically. I invite you to see what’s growing and blooming inside the Cactus and Succulent House during the height and blight of winter. One reason these plants are so popular and sought after is because the leaf forms are often so pretty that the flowers simply become a bonus or means to produce seed. In their natural habitat most of the succulents from the Southern Hemisphere do their growing and blooming during the winter months. Some of my favorites this year are: </p> Ceropegia cimiciodora </em>– A creeping, leafless stem succulent with super-cool flowers that blooms almost all year-round. You would be hard pressed to find a cooler flower.</li> Stapelia schinzii </em>var. angolensis </em>– Fuzzy maroon flowers that smell like rotting flesh! What could be better?</li> Haworthia emelyae</em> var. comptoniana</em> – A solitary species with a very small natural range in the Cape Province of South Africa. It is prized and known for its beautiful white markings on the leaf surfaces, slow growth and difficult propagation.</li> Haworthia arachnoidea</em> var. setata </em>– In its native South Africa, it is known as papierrosie</em> (paper-rose) or spinnekopnes</em> (spider’s nest). Sign me up!</li> Haworthia </em>hybrid – </em>A special blend of species created by me, formulated for your enjoyment!</li> Albuca spiralis –</em> A bulbous curly leaf plant. Give your curly leaf bulbs as much light as you can during the growing season.</li> Albuca hallii</em> – Another curly-leaf plant, the spring leaf plant has a pair of cork-screwed shaped leaves.</li> Trichodiadema </em>sp. – A beautiful plant that gets covered in purple blooms, reminiscent of summer-blooming iceplant (Delosperma</em>), during the winter months. </li> </ol> I have been collecting these plants for 21 years and I am still finding the next amazing thing I have to have. If you need some plant inspiration while your own garden is sleeping this winter, come visit our collection of unique cacti and succulents in their full glory. </p> Gallery photos by Scott Preusser </em></p>
