City Gardener

Tens of thousands of native California fan palms ( Washingtonia filifera)  rise over the gardens and streets of Palm Springs. The fan-like leaves flutter and wave as the trees gently sway in the desert breeze. If a plant could be described as elegant, this plant would certainly be one. Delicate fibers peel away from the leaf blade as they age, giving the palm part of its name, filifera . The advantage of the fibers to the plant is uncertain; however, the fibers were used by the indigenous Cuhuilla tribes for tools and fabrics. It is no accident the city is named for the palm. For centuries the native Cuhuilla residents were vastly outnumbered by fan palms. For the Cuhuilla, the plant became an important resource for their tools and shelters. Even today, I wouldn't be surprised if the number of palms outnumber the residents of the current modern city. Bird's eye view over old Palm Springs neighborhood; fan palms are everywhere. In their native environment, the palms grow best al...

Finally, after three years... my plant vines have grown and spread to be green wall that I had hoped for. I'm not sure it would have taken as long if the plants were in a more humid, sunny climate, et cetera. But given our indoor Minnesota location - even with a southwest exposure - the vines have needed that amount of time to climb the six feet from the base to the top rungs of the metal grid supporting them. The result has been worth the effort. And to be honest, I didn't have to wait three years to begin enjoying the green wall. The vines were already attractive when only half way up the trellis. A metal grid is filled with mix of Epipremnum aureum cultivar "Marble Queen", Epipremnum aureum aka golden pothos, and Philodendron Brasil . Architecture of the green wall The initial intent of the project was to grow a green wall, in an apartment, that could be moved around to be able to clean underneath, and also to provide a mobile room divider for our open-plan loft....

The assignment for my four-hour volunteer shift at the University of Minnesota Conservatory greenhouse was clearly listed on a whiteboard, with my name attached. Since most of the tasks involved working with strings of overhead cables or air tubing, much of my shift was spent at the top of a ladder. Vining plants are limited to only a few of the many benches in the greenhouse. Steel cables are strung above the benches to support their growth. Because many plants grow in a small space, part of the challenge is to untangle and separate the vines so that they don't strangle each other. Not many of the vines are blooming at the moment, as it is winter. However, Thunbergia grandiflora is producing a few lovely blue flowers (its tendrils grow clockwise, hence the common name Bengal clockvine). It's a popular houseplant, but it has become an invasive weed in parts of the world, like Australia, especially around waterways. Thunbergia grandiflora; notice small brown scale insects sucki...

Today, I returned to volunteer at the University of Minnesota Botanical Conservatory for another shift. It was once again a pleasure to roll up my sleeves and continue the never-ending task of cleaning insect pests off the plants. My assignment was limited to a small area: a bench holding about two dozen plants. Each one had to be inspected for pests, cleaned with soapy water, and sprayed with a solution of essential oils to deter further infestation. While working, I couldn't help but wonder about the efficacy of spraying the plants with clove and spearmint essential oils. Do they really work as well as synthetic pesticides, which are specifically designed to kill insects? How much credible literature supports the use of plant oils as insecticides and repellents? And do they work against all insect pests, or only certain species? A brief search in Google Scholar produced thousands of articles spanning many years, addressing the use of essential oils in agriculture. It's defini...

I didn't know that the cardboard palm - Zamia furfuracea - is a cycad. It isn't a palm tree (don't judge me, I'm not a botanist). But it also doesn't look like the other more familiar types of cycads with their fluted upright palm-like fronds. I didn't know it is said to be the second most commonly cultivated cycad, after Cycas revoluta . I didn't know this plant is unrelated to the common ZZ plant - Zamioculcas zamifolia - although they have a similar appearance. Before today I didn't know any of these things, but now I am happy to have learned them. From the parking lot I walked to the U of M Conservatory greenhouse in near-zero F weather. Stepping into the tropical spaces was a joy of its own. But being able to learn new information and experience new procedures was a compounding factor. Joy squared. During my 3-hour volunteer shift, my initial task was to clean the parasite critters (mealybugs and scale) from the stems and leaves of the cycad, Zami...

Whether in our homes or workplaces, we all have a routine for cleaning things. But often apart from our routine, there are those hard-to-reach places where dust or other bits collect. Over time, the buildup of debris can be a shock when the existence of these neglected spots is finally realized. Today at the U of M Conservatory greenhouse, where I am a volunteer indoor gardener, I spent my 3-hour shift reaching into out-of-the-way spaces to sweep, rinse, or wipe away fallen debris. I focused my efforts on the public area of the conservatory where new guests are more likely to see dusty surfaces that have escaped recent routine maintenance. A similar form of untidiness is the sudden realization that a particular plant has grown immensely since the last time you noticed it. The leaves have overspread the space and blocked much of the sun light for everything below. It is time to prune away the excess. My task for today included pruning the largest plant in the collection, a tree fern nat...