City Gardener Sandbox

Today's task was to tend to a sickly ficus (fig) tree located in the tropical rainforest room of the University of Minnesota's Conservatory. Ficus henneana is in the strangler fig family. The plant is native to Australia and nearby islands in the south pacific. It produces small fruits which are edible, but not very tasty to humans. The specimen in the Conservatory's collection has for months suffered an infestation of hard scale insects, and possibly mealybugs as well. The tree sits in a large pot measuring 24 inches diameter. The tree has grown to be about 4 meters high.  The leaves of this ficus are supposed to be dark green, but every leaf on the tree has been infested by several scale insects sucking out the sap and depositing sticky honeydew sap. Sooty black mold has thrived on the honeydew, turning the leaves black and blocking light from reaching the leaves.  Also, under the stress of the infestation the leaves have all acquired yellow spots, distributed in a unifor...

The outside temperature today was very cold and windy, two-degrees Fahrenheit with a windchill factor of -17 F. Walking to the University of Minnesota Conservatory Greenhouse from the parking lot - about a half mile away - was bracing to say the least. So today, it was an added pleasure to work in the relative warmth of the tropical rainforest room at the Conservatory.  Vanilla blossom I arrived at the greenhouse to find all of the staff busy and engaged in various activities. On the whiteboard were listed several tasks available for the choosing. I saw one of the tasks was to clean the aquatic plants in the tropical rainforest room. I thought it would complement similar work I did a couple weeks ago in one of the adjacent rooms. Aquatic plants in the tropical cloud forest room Many of the plants in the aquatic tank are currently dormant for the winter. They had wilted leaves and stems from last season's growth. The dead material is a source of rot and fungal overgrowth that might ...

Today I was scheduled to volunteer at the University's greenhouse, my shift was to run from 10:00 am to 3:00 pm. However, early this morning the University sent out a general notice to students and staff that there was a credible threat of gun violence made by a 42 year-old man, specifically targeting the University campuses. The suspect's name was known to them but was being withheld pending apprehension. In response, the University was closed, except for certain personnel, to be behind secure doors. Rats! Rather than lose a day of garden work, I took the opportunity to make pesto using the microgreens I've been sprouting in my apartment. Pea shoot microgreens I've been growing - well, really it is sprouting - microgreens for about a decade now. I'm not a huge fan, but I do produce a tray or two every couple of months. Each harvest is more than I can use so I’ve been converting most of the it into pesto. I particularly like fresh pesto for all sorts of dishes from ...

As most people know, plants absorb CO2 from the air and use it as a carbon source for building stems, leaves, and almost all of the other carbon-based molecules in the plant.  Plants also absorb oxygen from the air to produce energy and absorb water through their roots from moisture in the soil. It is important to allow enough air to get to plant roots. Too much water will drown the roots and starve the plant of oxygen. So it is curious to discover plants that have evolved to prefer their roots to be immersed in water. How do they survive?  Today's assignment was to prune and clean some of the water plants in the tanks of the collection room #3, representing a subtropical climate. To address the question of how plants survive with very wet roots, I'll highlight two plants with different adaptations to wet feet. Most of these plants in the two tanks of the subtropical room C3 have finished growing for the year and have entered domancy until spring. Winter is a good time to clea...

Volunteering at the University of Minnesota's Conservatory Greenhouse As mentioned in prior blog posts, for the past three years I've been volunteering for a few hours a week at the Conservatory greenhouse at the St. Paul campus of the U of M.  This blog is about activities there, and the many fascinating and beautiful plants in the collection. A little background about plant infections Everyone who has cared for a plant, from houseplant lovers to professional nurserymen, has learned the hard lesson that plant pests and diseases are an inescapable fact of life. All plants, domestic or wild, are susceptible to the infectious agents and parasites. Plants in their native habitats are largely protected by the ecosystems surrounding them, where pests do not have the luxury unfettered consumption. Plants grown indoors have been removed from their ecosystem and they are sitting ducks for parasites to proliferate unchecked.  Indoor gardens rely entirely on pest control methods with va...

The following is an addendum to my post of December 28, 2023: As I moved through the Conservatory's collection four rooms cleaning window sills, I had to handle many fascinating and endangered plants. I didn't have time to stop and appreciate them individually. But there were a couple notable exceptions where I just had to stop and admire the beauty, particularly the orchids.  Cattleya orchid It is late December now, many orchid species are in full flower at this time of the year. They respond to cool nights in the 50s F and sunny days. Two species in common houseplant cultivation are the cattleya orchids with the familiar wide tongue-shaped leaves, and the cymbidium orchids with their reedy strap-like leaves. The flower shapes are also slightly different. There is huge variation in the orchid family (28,000 species, in every type of habitat except on glaciers). I've posted photos of some of my favorite orchids in the greenhouse in prior blogs - including a species from th...

It's almost a tautology, or at least a cliche, to say all great gardens are built on great soil. But when looking at a plant what do we see? We see the parts above the ground and think that is all there is to the plant. But the aerial parts depend almost entirely on roots for water and essential elements; and, the roots depend on their surroundings...the soil. The soil has to contain the correct amount of minerals, water, oxygen, etc. If any one of these requirements aren't just right, a particular plant cannot grow well in that particular soil. Of course, different plants have adapted to different types of soil: dry sandy soil, wet clay soil, richly organic soil, or soil that is so inorganic that it's essentially chalk (yes, some plants prefer to grow in chalky soil). With those general comments about soil in mind, today my assigned task involved mixing ingredients to produce a soil used to support the majority of the tropical plants in the Conservatory's collection. A...