Skip to main content

Quercus (oak) maintenance

Making the rounds

Before starting my shift as a volunteer at the University of Minnesota Conservatory Greenhouse I enjoy walking around to see what plants are in bloom, and I also check on my prior projects to see how they have progressed over time. Today I noted the corpse plant was in full bloom.

It is a sure sign of spring when the corpse flowers are blooming (Amorphophallus titanum). From the tropical forests of Indonesia, it has one of the largest flowers in nature. When it blooms, the large red and green "flower" spathe may measure up to a meter in diameter. It has a scent similar to rotting flesh, the color is dark red like meat, and the central flower spike (spadix) heats up to body temperature. All of these features are helpful to attract insect pollinators.

Corpse flower (Amorphophallus titanum)

Oaks

There are several species of oak trees (Quercus) in the Conservatory's collection. For a long time 16 of them have been used as part of a research project. Located in a separate small greenhouse, all 16 oaks are to be repatriated to the Conservatory in the future. To do so they first need to be cleaned up, re-staked, and repotted in some cases. 

At some time in the past few months the 16 oak plants were the unintended bystander recipients of a fine spray of white wash. White wash is frequently used by green house managers to coat the greenhouse glass to act as a sunscreen for the plants.  As a result, many of the oak leaves were coated with fine white particles which are unsightly, and the powder is possibly causing the photosynthetic potential of the leaves to be reduced.

My chore for the day was to clean the white wash off the leaves, stake, and repot the trees as needed. In my three-hour volunteer shift I was able to clean and repot three oak plants. I figure the group of 16 oaks will take many more hours to prepare before moving them into the Conservatory. The three species for today were: Quercus douglasii, Quercus chrysolepis, and Quercus aristata.

Oak species waiting to be cleaned

Quercus douglasii is a native of parts of California. It is a large and long-lived tree known for being drought tolerant. It has the common name of blue oak for its leathery blue-green leaves, which have lobated edges. The leaves are deciduous. The pollen of the tree is highly allergenic. The acorns are an important food source for wildlife and livestock.

Quercus douglasii

Quercus chrysolepis, or canyon oak, is an evergreen oak native to western Mexico and the California coast. It also has flat leathery leaves with prominent spines on the leaf edge. It tends to be found along stream beds, hence the name canyon oak.

Quercus chrysolepis

Quercus aristata is another evergreen oak tree native to western Mexico. It grow no taller than 40 feet. It has stiff leathery leaves with sharply serrated edges when mature.

Quercus aristata

The orchids are still flowering this spring.

Cymbidium schroederi, native of China and Vietnam



Labels:

Comments

Post a Comment

Popular posts from this blog

A Sensitive Plant and Common Weed

Mimosa pudica, also commonly called the sensitive plant  was a popular houseplant when I was growing up in the 1970s. It was popular for its ability to quicky change shape by folding up its leaves to protect them from herbivore predators. At the slightest touch the plant is able to expell water from special cells in the leaves, changing the shape from frond-like to a stick-form. The plant creeps along the ground, never for than a foot or so in height. In tropical parts of the world this plant is considered and invasive weed. Today, as I was treating plants to remove pests I happened to touch the leaves of a Mimosa pudica , one with a pretty puff-like flower. Sure enough, the leaves all folded up to almost nothing. Mimosa pudica , the sensitive plant Other more routine chores during my four-hour shift at the U of M Conservatory included cleaning three plants of Hibiscus clayi, native to Hawaii. These three plants in particular have suffered repeated infestations with a variety of in...
Post a Comment
Read more

Bog Monsters

As a layman of botany the idea of carnivorous plants has perplexed me. The capturing and eating of other creatures seems like it ought to be limited to animals, since animals are mobile and plants are not. Almost all plants survive and thrive in the world through photosynthesis. They do not need to feed on animals to survive. But, what about the group of plants that are carnivorous? As stationary plants, why and how do they eat critters? This topic was stimulated by my assignment today at the Conservatory Greenhouse of the University of Minnesota. My task was to clean several large tanks of water filled with aquatic plants. While cleaning the tanks I realized many of the plants were classified as carnivorous . What is it about the aquatic environment that causes plants to eat - in effect - other creatures? The short answer is carnivorous plants evolved in nutrient-poor settings such as pond water which is naturally low in the amount of nitrogen needed to synthesize proteins. To compens...
Post a Comment
Read more

Rebuilding the support for vanilla vines

Raining in February   The morning began with a walk in the rain from my car to the Conservatory greenhouses - in the month of February. According to the calendar, we should be in the depths of winter. The precipitation today should be snow not rain. The storm system that we're experiencing is probably related to drenching rains moving inland from the west coast. I met Coordinator A... at the door of the Conservatory. His office desk faces one of the main doors to the building. He cannot escape observing everyone who enters...poor guy, it must be distracting for him. Anyway, as soon as I entered the building we started to discuss his plan for my activity of the morning. He offered me the project of rebuilding the support for vanilla vines which have been suffering from overexposure to sunlight and dry air. A bit of background The vanilla plant (Vanilla planifolia) is in the orchid family. It is native to Central America and Mexico. The seed pods were used by the Aztecs to flavor coc...
Post a Comment
Read more