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Green Roofs Might Invite Pests 02-20-18 | Legislation

Green Roofs Might Invite Pests
Denver Struggles with Keeping Foreign Species at Bay

Denver's city ordinance requiring green roofs faces obstacles because some issues haven't been studied yet. Certain plants may invite invasive pests such as the Japanese beetle, which are not native to the area.

After passing a city ordinance requiring buildings to include green spaces on their roofs, Denver is grappling with the question of what to plant in these new spaces.

Green roofs are still relatively new concepts and now the city is facing a dilemma of what to plant without disrupting the ecosystem.

The primary concerns are birds and insects, which are likely to make their way onto green roofs. However, certain plants may attract foreign pests to the area.

The ordinance does acknowledge the biodiversity made possible for plants, such as bees and insects; it does not outline what steps to take in preventing insects and animals not native to the area from moving into the area.

Some are suggesting only growing native species to promote a healthy local ecosystem.

In Denver, green grass and roses are popular choices for the new green spaces, but they are not native to the area. In Denver green lawns are sparse and not naturally occurring.

This can potentially lead to invasive pests such as the Japanese beetle making a home on green roofs and pushing out the native species. The beetle has recently been terrorizing rose bush owners in the metropolitan area.

Japanese beetles are also known to infest lawns and resist pesticides due to their ability to survive under the soil.

For now, the ordinance will continue to be enforced and over time the impact on the local ecosystem will become clearer.