I wasn’t sure if I should write about a plant that few people are aware of or ever notice. But watching a short YouTube video convinced me.
In the video, scientists placed a small wheat plant and a small tomato plant in a pot about 8 inches apart and then put a small dodder seedling between them.
With a time-lapsed camera focused on the pot, it was amazing to see during the following days the dodder swinging its growing leafless stem in a circle to determine which plant to attach to. In nine out of 10 trials, it went to the tomato. They then did further experiments, putting the scent of a tomato plant in an open test tube and found the dodder drawn to the test tube.
I was first made aware of this parasitic plant by former Quarry Hill student Andy Pruett. He had seen dodder growing in the Quarry Hill oak savanna and wondered if I was aware of it. With no as an answer, I got directions from Andy and took a look for myself.
What I found was quite amazing, with the pencil-lead thin golden stems of this plant spreading over the top of other savanna plants.
I then read a little bit about dodder and learned it was a parasitic plant, deriving its nutrients from the host plants it was growing on and attached to. But it was not until recently I saw dodder in two other locations and, in my retirement, had the time to investigate further. What I found, including the YouTube video, intrigued me.
Dodder seeds germinate in the soil. They produce stems that may grow a foot tall in a week or so, but they can only survive a few days longer if they do not find a suitable host plant to wrap around. If they do, they soon stab modified roots into the host plant stem, tapping into its vascular system and sucking out water, minerals and nutrients. Once established with a suitable host, the connection to the dodder’s soil root is severed.
There are close to 200 species of dodder worldwide, with some being found in temperate climates, but most preferring tropical or subtropical regions. It is related to morning glory, another vining species that’s not parasitic. Leaves are just tiny scales on the dodder vines and carry out very little, if any, photosynthesis. Dodder are annual plants, so before dying in fall they produce huge numbers of seeds to begin the process again the following spring.
When found in agricultural areas, dodder can be a problem and weaken the host plant, allowing disease to spread more easily. Although I have not seen or heard of dodder infestations in these plants, it can supposedly do a lot of damage to crops such as alfalfa, clover, flax, hops and beans.
Given my most recent findings of dodder in two different locations, Silver Lake Park and the Mayowood bike trail, I suspect hundreds of residents and visiting trail walkers have been within inches of dodder without knowing it. The dodder I found along the Mayowood trail covers plants in an area approximately 60 feet by 60 feet, right next to the blacktop, so should be easy to see with its bright golden coloration.
I find the story about dodder to be quite interesting and just wonder how the evolutionary process played out leading to such an odd plant. Or, for those not believing in evolution, I would wonder how a creator would have dreamed up such a plant?
I would appreciate hearing from others who previously have been aware of dodder’s presence throughout the city or on crops in rural areas. I’d also be interested to know where you’ve seen it or if you were able to find it in one of the spots I mentioned above.