Green Roof Alliums

Extensive green roofs generally weigh between 12 50 pounds per foot versus 10 12 pounds foot for a conventional roof and 80 150 pounds foot for an intensive green roof not including snow.

Green roof alliums.

An allium is a member of the onion family hence the name. Sedums and other low growing succulents that need little water and can survive in. Root rot may be a problem in waterlogged growing media but poor drainage should never be a problem on a properly designed and installed green roof. Nodding onions are also sometimes referred to as lady s leek.

It is native across canada and the eastern us. Two alliums that are useful on green roofs are allium cernuum and allium. Another allium that is native to the north america is the prairie onion allium stellatum. The sides of the roof may also need to be built up to accommodate the additional layers.

The combination of elevated temperatures wind exposure and high light provide challenging conditions for plant growth. Plant selection requires careful consideration of site microclimate substrate and maintenance factors linked to the desired aesthetic functional and management outcomes for the project. While varieties of succulents and cactuses as well as short grasses from the allium family have proven to be successful green roof plants nothing seems to succeed like sedums. Nodding onions on a green roof in edmonton canada.

Nodding onions on a green roof in edmonton canada. Foliage colors can vary from green to yellow red and blue and flowers from white yellow and pink to reddish. Alliums north america. Known for having leaves that look as good as it flowers turkistan onion is among the shorter ornamental allium varieties.

Foliage may remain green in some locations or in mild winters. Various low growing 6 10 tall alliums can be used for accent and they typically have green or bluish foliage and flowers of white pink or purple. Green roofs are hostile sites. For a green roof you need small hardy perennial plants that don t need much tending.

One of the favourites that we have seen in canada is nodding onion allium cernuum. A large and diverse genus of flowering plants with some 600 species sedums can shut down their systems in extreme heat and drought to keep from losing water to. It works well when planted in groups in rock gardens border fronts containers and window boxes its pink flower heads are 3 6 inches across held above 3 4 inch wide gray green leaves. Alliums have no serious insect problems as the sulfur compounds they produce apparently help ward off insect pests.

Like chives it is also edible.