Green Roof Alliums

Plant selection requires careful consideration of site microclimate substrate and maintenance factors linked to the desired aesthetic functional and management outcomes for the project.

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. 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. 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. Nodding onions are also sometimes referred to as lady s leek.

One of the favourites that we have seen in canada is nodding onion allium cernuum. Known for having leaves that look as good as it flowers turkistan onion is among the shorter ornamental allium varieties. It is native across canada and the eastern us. Nodding onions on a green roof in edmonton canada.

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. Allium summer beauty creates a visually noticeable vertical accent adding some height to an extensive roof planting while increasing the potential for biodiversity. Foliage colors can vary from green to yellow red and blue and flowers from white yellow and pink to reddish. Alliums have no serious insect problems as the sulfur compounds they produce apparently help ward off insect pests.

Another allium that is native to the north america is the prairie onion allium stellatum. An allium is a member of the onion family hence the name. The sides of the roof may also need to be built up to accommodate the additional layers. Sedums and other low growing succulents that need little water and can survive in.

Nodding onions on a green roof in edmonton canada. Foliage may remain green in some locations or in mild winters. 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. Like chives it is also edible.

Two alliums that are useful on green roofs are allium cernuum and allium. Alliums north america. Green roofs are hostile sites. An allium is a member of the onion family hence the name.

Aside from chives there are a few native ones in north america that can used.