Blotchy patches, serpentine lines, and small black dots inside a clear section of leaf – these are all symptoms I look for when diagnosing leaf miner damage. Leaf miners are the larval form of a few species of flies that live within the upper and lower surfaces on the leaf and feed on the cells inside.</p> Typically, it is nothing more than an aesthetic nightmare. But on plants used for edible greens, like spinach, it develops into a problem that requires management, as leaf miners can decimate a crop, rendering it inedible.</p> The leaf miner flies lay eggs on the underside of the leaf, and once the eggs hatch, bore into the inner space of the leaf. Once inside, they munch on the inner cells, leaving a trail behind filled with small black frass (insect poop) inside the tunnels. After maturing, the flies emerge from the leaves and begin the cycle again. In the fall, the larvae pupate and fall to the soil to overwinter. These insects can have multiple cycles within one year.</p> Depending on the severity of the infestation, there are a number of management techniques available. Spraying insecticides is an option, but the timing is crucial – once the larvae are in the leaf, contact insecticides will not work. Systemic are an option, but have other negative consequences including affecting pollinators and other beneficial insects.</p> The most effective methods of control in a vegetable garden include tilling the soil to disrupt the pupae in the winter, remove the leaves as mines develop and squish the eggs on the undersides of the leaves. Doing a combination of all of these things can prevent a complete decimation of your fresh edible greens. In a perennial bed, however, most opt for either removing the leaves or just ignoring them. </p>
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>
</p> I'm the Doctor of Plant Health Horticulture Intern at Denver Botanic Gardens this summer. My internship is focused on plant health, with diagnostic projects ranging across topics including nutritional deficiencies, insect pests and diseases. I am working with horticulturalists here at the Gardens on projects like the Arboreal Arthropod Diversity Survey. This survey is designed to determine the diversity of insects present on 17 tree species throughout the Gardens, and assessing the health of the soils around 10 palm trees in the Boettcher Memorial Tropical Conservatory. In addition, I am giving Science Chats at the Science Pyramid and providing diagnostic support to the horticulturalists and Master Gardeners on a weekly basis.</p> My internship goes in so many different directions because I am a student in the Doctor of Plant Health Program</a> at the University of Nebraska – Lincoln. This interdisciplinary program is a practitioner doctorate degree, designed to train plant practitioners capable of examining and diagnosing problems in a wide variety of plant systems. With this degree, I aspire to work in regulation, specifically managing the introduction and spread of invasive species that will impact agriculture and horticulture on a local and global scale.</p> But, the part you’re probably more interested in is what I am doing in this space—part of my internship is public outreach. In addition to hosting Science Chats and providing diagnostic support, I will be publishing a regular plant health highlight post here on the Garden’s blog. These highlights may range from information on a disease or pest you may see in your backyard to interesting things the horticulturalists are doing to manage problems faced in the gardens. Because of my diverse training, expect there to be a number of articles over a wide range of topics.</p> Enjoy the Plant Health Highlights, and if you see me around the Gardens, say hi!</p>
When coming to the Gardens to enjoy springtime blooms, you may be surprised to learn that we also incorporate wildlife observations into some of our research projects.</p> One such research project uses a system of motion-sensing trap cameras strategically placed along Deer Creek at Chatfield Farms to monitor wildlife activity. Deer Creek cuts diagonally through the 700 acre property and serves as a hub for many types of wildlife including (but not limited to) deer, beaver, raccoons, waterfowl, coyotes, skunk and even the occasional bobcat. In collecting several years of data, we are now noticing clear patterns in seasons, time of day, creek flow, etc.</p> Under the supervision of Dr. Rebecca Hufft, associate director of applied conservation, I have been managing the trap camera program. Once a month, I make the trip down to Chatfield Farms to service these cameras. This involves swapping out eight batteries per camera (rechargeable, of course) as well as an SD card. With this fresh data in hand, I then make a visit once per week to the York Street location to audit the photos and footage from the previous month’s data. I look forward to these volunteer shifts all week and often reward myself with a walk around the Gardens after I have finished my audit for the day.</p> If you have land and are curious about which critters frequent your property, you can set up your very own trap camera. Many options are available online for under $100, and YouTube provides a number of tutorials on how to set these up and service them. You never know what you may find in your own backyard!</p> Please enjoy some of my favorite gems below.</p> This blog post was written by Christina Brandt, a volunteer in the Research & Conservation Department.</em></p> </iframe></p> Raccoon (Procyon lotor</em>) - Downstream camera - 4/15/2017, 5 a.m.</p> </iframe></p> Coyote (Canis latrans</em>) - Downstream Camera - 7/14/2017, 8 p.m.</p> </iframe></p> North American Beaver (Castor canadensis) - </em>Downstream camera - 6/3/2016, 2:23 a.m.</p>
Sneaky Spines and Careful Measurements</h3>Sweeping western slope views, slightly menacing rain clouds and beautiful, tough plants surrounded us. I listened for my field partner to shout out cactus dimensions and wrote each number into its proper cell on the data sheet while picking prickly pear spines out of my hand (more seasoned Coloradans seem to avoid this indignity). Spine-avoidance wasn’t the only thing I learned when I joined the annual Sclerocactus glaucus </em>monitoring expedition</a> last year, one of several long-term scientific research projects in which Gardens staff and volunteers check in on populations of rare plants. I’m grateful for all I learned about the species, its habitat, and the craft of field botany. Plus, now I know that young cacti are called "pups."</p>Alternately giddy with the thrills of being out in the wild with amazing scientists and naturalists, and uncomfortable from kneeling between plants over long days in all weathers, what kept me going was the fact that we were collecting important information to help manage this rare species. Now, finally, after compiling all the information over the winter, the results are in! You can see some of our findings and catch up on recent progress across the many, many research projects at the Gardens in the 2017 Science Year in Review</a>.</p>Sclerocactus glaucus</em>, endemic to western Colorado, is federally listed as threatened, under pressure from energy extraction, other human development and, occasionally, cactus poachers. By counting plants and characterizing their life history traits in the same locations annually, we can learn about the basic biology of this species and how it responds to long-term environmental variation. Each year, we locate every Sclerocactus glaucus </em>plant within the same defined plots and measure each plant’s height and diameter with calipers, recording any signs of flowering or damage from herbivores. With this information, we can answer questions like: How fast do individual cacti grow? Which bloom? How many new young plants do we see? This dataset also allows us to monitor the health of these populations, tracking local year-to-year growth and decline. Our results are critically useful to our collaborators at the Bureau of Land Management and the US Fish and Wildlife Service.</p>On the whole, the 2017 count totals show that our Sclerocactus</em> glaucus </em>populations are doing pretty well. There was a slight increase from 2016 numbers, with generally stable populations in recent years, and there are far more cacti than in 2008 when the study was initiated. In total, our team of 11 people counted and measured more than 1,000 individual cacti at 10 locations last year.</p>In the moment of performing most research tasks (like recording a cactus diameter), it’s easy to lose sight of the larger purpose. Fieldwork is great fun, but it is also deeply satisfying to look back on the results of our work in context.</p>This blog post was written by Jessie Berta-Thompson, Ph.D., adjunct researcher with the Research & Conservation Department at Denver Botanic Gardens.</em> </p>
