Tending an Australian Ficus henneana tree

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 uniform pattern across each and every leaf on the tree. I'm not sure what is causing the yellow spots, Coordinator A... thought perhaps the plant has been overwatered, adding to the stress the plant has been experiencing.

I found a tall ladder which allowed me to reach all the way to the top of the plant. With a bucket of soapy water attached to the top of the ladder I was able to scrub the sooty mold and insects off of each leaf. I'm sure I missed a few leaves and insects, but the burden of insects has been significantly reduces, and the sooty mold has been largely removed. The plant will now have a better chance to fight off future infestations.

I noted that there were several beneficial predator Cryptolaemus larvae on the plant, so they may also continue to keep down the population of scale insects.

Ficus henneana leaves

Ficus henneana

Nearby the ficus tree, I spotted a jewel orchid (Ludisia discolor) in full bloom. This orchid is popular among orchid growers. I see it is available locally at some plant shops. The plant has showy dark leaves with attractive pinstripe. The flowers are small and not particularly colorful, but the spikes are tall and attractive.

Ludisia discolor (jewel orchid)

Comments

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...

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...

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...

City Gardener

Search This Blog