Skip to main content

Desert-adapted Orchid, Etc.

It was a lovely day for a cycle ride in May. I was happy to be able to cycle to volunteer for a few hours at the Conservatory Greenhouse on the U of M's St. Paul campus. There, I was allowed to pick chores from a list written on a white board in the head house, or control room of the Conservatory. Among the tasks were vine maintenance and pest contol - with and without chemicals. Along the way I saw lovely and amazing orchids in full bloom. 

Desert-adapted orchid

When I think of orchids the image I have in my head is that of an epiphytic plant clinging to the branch of a tree in a damp jungle. But I was surprised to discover the existance of an orchid growing in the rocky granite soil of the desert room. The plant is native to Kenya and South Africa where it grows in full sun on rocky outcropings. The leaves are stiff and spiky like an aloe plant. The flower spikes can be up to 2 meters tall; I suspect height is so that pollinators can locate them in the rocky environment where they evolved.

I noticed the presence of this plant in the desert room last year as I was cleaning dead leaves and debris from the beds. I have been waiting until today to see the plant in full bloom. It was exciting to see it finally happen!

Relevant to the desert orchid are a few factoids from the web site of Kew Gardens:
- There are 28,000 species of orchids, divided into 850 genera
- Orchids are found in every climate zone, on every continent; even above the Arctic Circle
- There are more species of orchids than there are of living bird species

Eulophia petersii

Spiky leaves of the desert-adapted orchid, Eulophia petersii

Tulip orchid

Equally stunning for its shape and color is the tulip orchid, now if full bloom. This plant is native to the forest floor at high elevations in South America; think of the high Andes Mountains. It is interesting that actual tulip plants are also native to cool mountainous elevations, but of the Middle East not the Andes. Could this be an example of convergent evolution, where two unrelated plants evolve to appear similar to each other? They are both adapted to similar conditions, the shape of the flower must give them some advantage over other flower shapes. Perhaps the flower provides a sheltered microenvironment which a pollinator would find attractive in addition to the color of the petals.

Tulip orchid, Anguloa dubia, South America

Tulip orchid, Anguloa dubia

Vine maintenance

Today I chose to do one of the chores I frequently return to - the pruning of vines as they overgrow their little spots on the vine bench. Each vine plant given an overhead steel cable which they use for support. But some plants grow faster than others and - over time - are capable of completely overwhelming a slow-growing neighbor. Occasionally, the vigorous plants need pruning back to keep them all in line. 

Several vines, now disentangled

Pest control with essentail oils

Another recurring chore in the greenhouse is to keep the insect pest population under control. Today I used a commercial product, a mixture of essential oils, to spray on the leaves of plants to reduce the population of thrips insects. The dilute mixture of peppermint and clove oil is noxious to many of the pests in the greenhouse. It has the benefit of being non-toxic to people and plants. 

I was assigned to treat a bench of tropical plants - mainly cycads and zamia plants - with the essential oil solution. Every plant on the bench was sprayed using a hand-spray bottle, the plants were then doused with a sharp mist to drive off any clinging pests.

Cycad and zamia bench in the tropical collection room,

Sharp spray from a hose

In addition to non-toxic chemicals, some plants are treated with plain tap water to blast insects off from leaves which have grown to be out of reach by hand. In the photo I've used a ladder to get as high as I could to pelt the little critters with a strong spray of water.

Pest control, using a ladder and the jet setting



Labels:

Comments

Post a Comment

Popular posts from this blog

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

Frankincense and Myrtle: Fragrant Treasures

If you were raised in the Christian religion, you've probably heard of frankincense and myrrh. But, do you know much about them, beyond being fragrant commodities as precious as gold? Until today, I could not have described frankincense, myrrh, or citronella. But, by the time I was finished with my volunteer shift at the U of M Conservatory greenhouse I knew more about them. However, I will have to wait for another time to actually see a myrrh tree. I'm not sure if the Conservatory has a myrrh tree. I do know myrrh is in the Burseraceae family, the same family as the frankincense tree. They are not in the myrtle family as the name would suggest. The myrtles (or Myrtaceae) are the gum trees of the Australasia, one which gives us citronella (see below). Maintenance of small trees The day's duties assigned to me were to provide general light maintenance to a group of small trees located in the desert and subtropical rooms of the greenhouse. Maintenance included pruning and mak
Post a Comment
Read more

Infection control in the Conservatory, from mundane to amazing

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
Post a Comment
Read more