Friday, March 24, 2006
That Natural Environment
I grow a lot of plants that are not domesticated. They are clones of plants that were yanked out of some rainforest somewhere, or perhaps grew for seeds harvested in the wild. Not a lot is written about the care of some of these plants, but it's assumed that you need to mimic a plant's natural environment in order for it to grow best.
This has always made a certain amount of sense to me - you would think that each plant has evolved to do best in the environment in which it resides. Plant collectors (and it seems, orchid collectors in particular ) go to great lengths to record the physical attributes of the locations their plants are collected in, hoping that replicating those environments will help to keep the plants happy in cultivation. They take temperature, humidity, soil pH, water chemistry, light intensity and whatever else they can think of.
Yes, you would think that each plant has evolved to do best in the environment in which it resides, but as it turns out, if you thought that, you would be thinking wrong.
Plants grow in the places they grow for a lot of reasons, among them being competition, random chance, predation, and widely spaced catastrophic events. If you go to an environment where a plant grows like crazy 11 months out of the year and then dies in a yearly killing frost, you won't find that plant. You won't find the plant where it will be killed by sheep, migrating flocks of toads, or whatever else. You won't find the plant if it's going to be smothered by Kudzu. However, the plant might grow perfectly fine in these places without the predation, the catastrophes or the competition. These are the sorts of things I try to avoid in my greenhouse. and this is why I don't always put too much stock in information about where the plant does and does not grow in nature. There are just too many variables that hopefully won't occur in my greenhouse.
I've been reading a book recently called "Demons in Eden", which purported to be about the reasons behind and solutions to invasive species. Although material on this particular facet of things is fairly light, it's been a great primer on ecology and environmental niches. In this book, a very relevant experiment done by a German guy is mentioned.
This guy created an artificial experimental meadow, where he graded the soil such that the water table followed a gradient from over a meter deep to just under the soil surface. On this gradient, he planted strips of various small meadow species. He also planted a strip with all the species combined to mimic normal competitive conditions. He then grew the thing for a season, pulled up all the plants, dried them and weighed them. He was able to graph the mass of the plants vs the water table depth. What he found was that when planted separately, most of the plants did best where the water table was a medium depth. But when they had competition from other species, the peaks of their distribution were distributed all over the water table, each finding its own niche again. So the niche environments were only the optimal environments for the plants when they had competition. Without competition, they all grew better somewhere else.
So that orchid pulled out of the tropical forest might grow best for me outdoors in the snow? Unlikely. But the necessity of exactly duplicating the natural growing conditions is certainly in question. Most plants are happy given a little food, a little water, warmth and well drained soil. They are all survivors, and not necessarily perfectly adapted to the environment in which they are found.
This has always made a certain amount of sense to me - you would think that each plant has evolved to do best in the environment in which it resides. Plant collectors (and it seems, orchid collectors in particular ) go to great lengths to record the physical attributes of the locations their plants are collected in, hoping that replicating those environments will help to keep the plants happy in cultivation. They take temperature, humidity, soil pH, water chemistry, light intensity and whatever else they can think of.
Yes, you would think that each plant has evolved to do best in the environment in which it resides, but as it turns out, if you thought that, you would be thinking wrong.
Plants grow in the places they grow for a lot of reasons, among them being competition, random chance, predation, and widely spaced catastrophic events. If you go to an environment where a plant grows like crazy 11 months out of the year and then dies in a yearly killing frost, you won't find that plant. You won't find the plant where it will be killed by sheep, migrating flocks of toads, or whatever else. You won't find the plant if it's going to be smothered by Kudzu. However, the plant might grow perfectly fine in these places without the predation, the catastrophes or the competition. These are the sorts of things I try to avoid in my greenhouse. and this is why I don't always put too much stock in information about where the plant does and does not grow in nature. There are just too many variables that hopefully won't occur in my greenhouse.
I've been reading a book recently called "Demons in Eden", which purported to be about the reasons behind and solutions to invasive species. Although material on this particular facet of things is fairly light, it's been a great primer on ecology and environmental niches. In this book, a very relevant experiment done by a German guy is mentioned.This guy created an artificial experimental meadow, where he graded the soil such that the water table followed a gradient from over a meter deep to just under the soil surface. On this gradient, he planted strips of various small meadow species. He also planted a strip with all the species combined to mimic normal competitive conditions. He then grew the thing for a season, pulled up all the plants, dried them and weighed them. He was able to graph the mass of the plants vs the water table depth. What he found was that when planted separately, most of the plants did best where the water table was a medium depth. But when they had competition from other species, the peaks of their distribution were distributed all over the water table, each finding its own niche again. So the niche environments were only the optimal environments for the plants when they had competition. Without competition, they all grew better somewhere else.
So that orchid pulled out of the tropical forest might grow best for me outdoors in the snow? Unlikely. But the necessity of exactly duplicating the natural growing conditions is certainly in question. Most plants are happy given a little food, a little water, warmth and well drained soil. They are all survivors, and not necessarily perfectly adapted to the environment in which they are found.
