May 21st , Lincoln Park Zoo - Chicago

This roof is a sub irrigated one with 8 inches of media + drainage. The plants' diversity is its first characteristic because I found more than 20 different species: Thymus (photo underneath), Festuca, Dianthus, Sedums (of course! But some an unsual varieties: Sedum speotabile 'Robustrum'), etc...

Thymus serpyllum 'Coccineum'

You can understand that I was very happy to see that! Moreover the weed pressure was low. Even if patches of gloves were perfectly included into the wind protection net (it was not destroyed by the sun at all...).


I also noticed an important colonization of Euphorbia cypariasias ' Fens Ruby'. They were very dominant here. In fact in this season, a lots of species bloom like: Armeria Maritima (photo underneath) or Hemenocallis 'Stella D'Oro' (photo underneath).

Armeria Maritima

Hemenocallis 'Stella D'Oro'

I also see an interesting point: in the entire shadow part of the roof, grasses were healthy but not really the other species.
The difficulty for maintenance will be to kill the gloves patches because they are very stong into the net. Unfortunately spray herbicide is the best solution..