City Gardener Sandbox

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 var

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

Podocarpaceae (podocarps in English) is a very diverse family of conifers mainly existing in the southern hemisphere. They dominated the antarctic forest before the time of the dinosaurs, and remain in the cooler regions of the South America, Australasia and the Philippines. New Caledonia in particular has many native plants which survive little changed from the time when podocarp conifer forests covered Antarctica, nearby islands, and Southern continents. Today, I cleaned the moldy leaves of the podocarp called Retrophyllum minus. This small tree-sized conifer has roots that prefer to grow in running water! It is the only conifer know to do so. The greenhouse has two small trees in its collection, both sitting together in a small pool of bubbling water. Retrophyllum minus (Podocarpaceae) To clean the plants, I lifted the pots out from the water pool onto a stool at about knee-height. I could access all of the needle-like leaves with a sponge of soapy water. Thankfully, the leaves were

There are many recognized types of biomes on earth, scientists disagree on the number, but some estimate up to eleven different types. Displayed at the U of Minnesota Conservatory greenhouse are four different biomes selected for their diversity of plant life: antarctic forest, diverse desert, mediterranean scrubland, and ancient rainforest. Today, Coordinator A.. asked me to help clean the beds in the Diverse Deserts display. This room is open to the general public, and it gets quite a bit of traffic compared the to collection side of the greenhouse which is not open to the general public without appointment or supervision. The Diverse Desert Room, D4, has four large beds filled with desert plants. The ground cover between the plants is made of granite pebbles. As time passes, leaves and other detritus from the plants fall to the ground cover, gradually coating the surfaces with debris. Today was the day to get down on hands and knees and clean out the debris from the granite pebbles.