Alliums are always a great choice for green roofs. Furthermore there are native allium species across North America and Europe (including the UK and France. In fact Allium schoenoprasum, one of the most commonly used has a circumpolar distribution. Called chives in English, it is a widely used herb.
Species lists for US and Canada
We are using these plants to alert people to recent additions inside the guide. We have now create lists of native green roof plants for Quebec, eastern Canada and Ontario. Many of these will be appropriate to north eastern US. We have also added a list for the mid-west US – again many of which will be appropriate for central Canada. Further lists to cover other areas will be added in the near future.
Chives flourishing during long spring drought 2011
Alliums – North America
Aside from Chives, there are a few native ones in North America that can used. One of the favourites that we have seen in Canada is Nodding onion (Allium cernuum). It is native across Canada and the eastern US.
Nodding onions on a green roof in Edmonton, Canada.
An allium is a member of the onion family, hence the name. Nodding onions are also sometimes referred to as Lady’s leek. Like chives it is also edible.
Another allium that is native to the North America is the Prairie onion (Allium stellatum). The plant’s latin name refers to the starry shape the umbels of the flower make. This species is found across central Canada and the mid-west of the US.
All alliums are attractive to wildlife, especially butterflies and in North America even hummingbirds. However, bears are rather partial to alliums as well, but how they get onto the roof is an open question!!!!
Hardiness – Alliums are where it is at
The great thing about native onion species compared to non-native more showy ones, is their hardiness. Our experience of extensive droughts in south eastern England is that the one plant that positively thrives in these conditions is chives. So all in all native alliums are a great choice. Hardy, attractive to look at and for wildlife they are definitely one to consider.
