Green Roof Plants - How do They Survive
Written and narrated by Dr. Anna Zakrisson for Purple-Roof.
www.purple-roof.com/
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Pests and green roof plants
During which parts of your life did you get the most infections? If you’d allow me to make a qualified guess, I’d probably say that it has been during times of high stress, mentally and/or physically. If we sleep little, eat poorly, and stress a lot, we tend to get sick.
In a way, this is also the case for plants, through their stress looks different. Plant stress can be things like too little (or too much) water, high UV radiation, too much shade, too little (or too much) nutrients, or nutrients in the wrong ratios.
Usually, one moderate stressor won’t crash a system, but if several of them come together, well, then you end up with sick plants.
Often, we apply pesticides and hope for the best. However, if the stressors aren’t being dealt with, we are just postponing the situation.
As an example, we were once asked to remove grubs that were eating up the green roofs in Montgomery County MD. Instead of applying pesticides, we recommended that we needed to remove plant stress. You remove plant stress, and the plants themselves can deal with the grubs. Pesticides fix the system short-term but mess it up even more long-term.
Pesticides are not only expensive but end up in downstream water bodies, which may destroy local ecosystems and risk violating local environmental regulations.
Furthermore, the symbiotic relationships between the plants and microbes such as mycorrhizae might be killed by broad-spectrum pesticides. Destruction of this type of symbiosis means lower water and nutrient availability for the plants, which in turn means more stress.
It is like applying a band-aid on a gaping wound.
We are much better off taking a close look at what is stressing the plants in the first place: let’s focus on sustainability.
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Read the article on the Purple-Roof blog!
www.purple-roof.com/post/green-roof…do-they-survive
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