In the Pacific Northwest of the United States, there is a problem with invasive English ivy taking over local wildlife (it is native to Europe and western Asia). It's gotten so bad that the plant is actually banned in Oregon. In order to combat the ivy plant that has taken over local parks, volunteers rip it out. If you have a problem with ivy in your area, or any other invasive plant for that matter, you can volunteer to remove and destroy non-native plant species.
The English ivy plant has its place, as long as it isn't a danger to any local plants. It's a great indoor container plant (it cleans the air), and you can keep it on a shady balcony garden without fear that it will choke out forests and create what are called "ivy deserts." If you purchase your plants and seeds from your local garden shop, you probably don't have to worry about your plants being invasive.
Even if you don't have a known invasive plant in your balcony garden, still make sure that any plants you have don't make it into wild areas. If you don't want a container plant anymore, never plant it in a park or wild area. Either give the plant to someone who wants it, or make sure that you completely destroy the plant before throwing it away. Some plants can keep growing, flowering and producing seeds even after they're pulled out or cut.
Most of the plants that balcony gardeners keep have soft tissue. So if you think you have an invasive plant, or if you want to get rid of a plant and have no one to give it to, throw the plant away in a heavy plastic bag. Make sure that the plants can't poke a hole in the bag. Other plant types can be burned, buried or drowned.