Tuesday, June 8, 2010

Island in the Sky

I discovered this interesting development along the creek. Flood waters have deposited a tight mass of debris in the fork of this fallen tree. The flood water came in from the right. A couple of large branches lodged against the fallen tree and formed a perfect strainer for collecting floating material. Sticks, grass, leaves and small bits of wood collected to form a tightly packed mass.

Seeds also travel in the flood water and several were collected at this point. It’s not uncommon for flooding streams to create ephemeral habitats such as gravel and sand bars, thick silt deposits or piles of organic debris. Seeds are frequent travelers on the flood waters, so it’s not uncommon to find a wide variety of plants colonizing these temporary conditions.

What makes this unusual is the fact that it is not connected to any solid ground. This collection of plants is perched above the water and any downward probing roots are going to pop out into air. This mass arrived early in 2009, so this will be the second growing season for the naturally occurring hanging planter.

You would expect a lot of annuals to be growing in a situation like this. Most annuals are adapted to exploiting any available growing medium, no matter how temporary. These are Spotted Touch-me not, Impatiens capensis. Their orange, trumpet shaped flowers hanging above the water should make a nice display later in the summer.

Hog Peanut, Amphicarpaea bracteata, is another annual that is quite common along the stream corridor. The bedstraw is a perennial and most likely began growing last year. As the organic matter in the mass decomposes, the entire structure will begin to weaken. Soon portions will break away and the mass will begin to shrink. As it shrinks, its ability to hold water will diminish and the plants will begin to suffer. It will be interesting to see how many species can colonize here before the population begins to dwindle.


  1. Boy do I have plenty of Touch-Me-Nots!! They have invaded one of my flower beds that is in a moist area----well maybe I should say I have invaded there space!!! :} Thanks again for your info and pictures!!!

  2. Fascinating. I'm enjoying learning from your posts.


  3. Woah this is so interesting! Thanks for sharing a small, but fascinating aspect of the natural world that often goes unnoticed.

  4. grammie g - Touch-me-nots are a wonderful plant. I think you could entertain an elementary school group all day by letting them explode the seed pods.

    Lois - I'm glad you find something useful in the posts. I seem to learn something new every time I go out for a walk.

    Green Gal - I'm happy to share. Even in the most tranquil scene, there’s a struggle to survive. When I look at plants, I often wonder how a particular individual managed to secure its place against a multitude of competitors.