Plant establishment on unirrigated green roof modules in a subtropical climate

Green roof The use of green roofs as a self-reliant and low-input tech­no­logy emerged in Europe, Scandinavia and the UK, where cli­mate con­di­tions are favour­able for main­tain­ing green roof veget­a­tion without irrig­a­tion. But how use­ful is this environmentally-friendly tech­no­logy in more hos­tile climates?

The applic­a­tion of green roof tech­no­logy has become more com­mon in the cent­ral, north­west­ern and east­ern USA, and is now being employed across the south­ern USA as well. However, there is little research in the lit­er­at­ure that eval­u­ated plant sur­vival on unir­rig­ated green roofs in sub­trop­ical cli­mates that exper­i­ence fre­quent drought and heat stress. A new paper in AoB PLANTS sum­mar­izes the res­ults of a study of plant estab­lish­ment on a mod­u­lar green roof in south-central Texas. Fifteen plant spe­cies were field tested in green roof mod­ules on a four-storey build­ing in College Station, Texas, with irrig­a­tion lim­ited to the first sev­eral weeks of estab­lish­ment. Climate data, plant growth and spe­cies sur­vival were meas­ured over three grow­ing seasons.

Green roof module

The estab­lish­ment and sur­vival of sev­eral plant spe­cies without any mor­tal­ity sug­gests that irrig­a­tion lim­ited to the first few weeks after plant­ing may be an effect­ive approach on green roofs in spite of the more chal­len­ging cli­matic con­di­tions in the south­ern USA. Since the cli­mate in south-central Texas had been con­sist­ently drier and warmer than nor­mal dur­ing the study period, longer-term research on these spe­cies is recom­men­ded to expand know­ledge of estab­lish­ment require­ments for these spe­cies under a wider range of con­di­tions, includ­ing wet­ter than nor­mal years.

Dvorak, B.D., & Volder, A. (2012) Plant estab­lish­ment on unir­rig­ated green roof mod­ules in a sub­trop­ical cli­mate. AoB Plants.


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