Loosestrife?

Question

is there reason to control the loosestrife and stop it from spreading?

Answer 1

First, let me note that there are a number of things called "loosestrife", and the one I think you're referring to with this question is "purple loosestrife", Lythrum salicaria, native to Eurasia.

I beg to differ with Curious Orange on the matter of its weediness, at least in North America. (I believe CO is in the UK?) Lythrum salicaria is a highly invasive, quickly spreading pest species of wetlands here, quickly becoming a solid monotypic stand that pushes native species out and changes the hydrogeology of the area. Because Curious Orange is in the native range of the plant, you see it with the insects and diseases that keep it down to a dull roar, biologically speaking. Here, it's bully with chlorophyll, one that can provoke mild-mannered wetlands biologists to roaring rages.

Here are a couple of photos taken 10 years apart:
http://www.npwrc.usgs.gov/resource/plants/loosstrf/index.htm

Here's some current information from a Cornell biologist.
http://www.invasiveplants.net/InvasivePlants/PurpleLoosestrife/PurpleLoosestrife.asp

Epilobium angustifolium, aka Chamerion angustifolium, is a native wildflower in North America, actually on the Endangered list in several states:
http://plants.usda.gov/java/profile?symbol=CHANA2

Answer 2

Lots of reasons to control loosestrife. Loosestrife is an alien or exotic species, meaning that it is not a native plant. It grows quickly in wetlands, ditches, damp roadsides, and so on.

1. Loosestrife grows in thick stands, so it takes over whole areas and doesn't allow the native plants to have enough light and living space to survive. It takes the place of native plants.
2. Loosestrife does not provide the same habitat or food sources as the native plants, so insects and other consumers that relied on those native plants are forced to move or die out.
3. Loosestrife does not have its natural enemies in its new location, so there aren't natural controls on its population. Some researchers are experimenting with an imported insect that feeds on the loosestrife.
4. Losing biodiversity (not having as many different kinds of living things in an ecosystem) upsets the stability of an ecosystem, making the organisms that live there less likely to be able to survive.

Answer 3

I answered your previous question that there is a confusion about names of plants. Lythrum salicaria is not an invasive pest. It is a beautiful wildflower, that only grows along rivers. Epilobium augustifolium is a very invasive pest that quickly spreads and it is sometimes also called purple loosestrife in the US.