## 4 Results
### Plant Selection: Key Results
#### 4.3.2 Plant Selection and Green Roof Development: In-Field Testing within the Prototype
A summary of the suitability of the annual and biannual plant species for the different light zones is shown in Table 3.  
Grass species: _Deschampsia cespitosa_, _Calamagrostis_ x _acutiflora_, _Carex ornithopodia_, and _Festuca gautieri_ grew successfully in all light zones. The vitality, flowering, and growth rate of _Bouteloua gracilis_ was better in the sunny zone. _Koeleria glauca_ and _Pennisetum alopecurooides_ did not survive at all. It was also clear that _Bouteloua gracilis_ and _Carex ornithopodia_ were very easily overgrown by dominant neighbors and therefore needed to have suitable adjoining plants. A summary of the suitability of the grass species for the different light zones is shown in Table 4. \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Grass Species**} & **Zone 1** & **Zone 2** & **Zone 3** & \\  & **360–260** & **260–160** & **<160** & **Comments** \\  & **MJ/(m2/year)** & **MJ/(m2 year)** & **MJ/(m2 year)** & **MJ/(m2 year)** & \\ \hline \end{tabular}
\begin{tabular}{c c c c} \hline \multirow{2}{*}{_Allium schoenophrasum_} & \multirow{2}{*}{x} & \multirow{2}{*}{x} & \multirow{2}{*}{x} & \multirow{2}{*}{x} \\  & & & & \\ _Beta vulgaris subsp._ Vulgaris & & & & \\ _Brassica oleracea_ convar. & & & & \\ _capitata_ & & & & \\ _Capsicum annuum_ & & & & \\ _Eruca sativa_ & & & & \\ _Foenticulum vulgare_ & & & & \\ _Fragaria vesca_ & & & & \\ _Lactuca sativa_ var. _capitata_ & & & & \\ _Mentha x piperita_ & & & & \\ _Ocimum kilinum x basilicum_ & & & & \\ _Origanum vulgare_ & & & & \\ _Phaseolus vulgaris_ var. _valgaris_ & & & \\ _Raphanus sativus_ var. _sativus_ & & & \\ _Solanum Lycopersicum_ & & & & \\ \hline \end{tabular}
\end{table} 
Table 2: Suitability of edible plant species for the three different light zones in the “PV Rooftop Garden” system (suitable species are marked with “x”). \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Annual and Bi-Annual**} & **Zone 1** & **Zone 2** & **Zone 3** & \\  & **360–260** & **260–160** & **<160** & **Comments** \\  & **MJ/(m2 year)** & **MJ/(m2 year)** & **MJ/(m2 year)** & **MJ/(m2 year)** & \\ \hline _Antirrhinum majus_ & & & & \\ _Calendula officinalis_ & & & & \\ _Echium vulgaris_ & & & & \\ _Echium vulgaris_ & & & & Self-seeded into test plot \\ _Silene vulgaris_ & & & & \\ _Verbascum nigrum_ & & & & \\ \hline \end{tabular}
\end{table} 
Table 3: Suitability of annual and biannual plant species for the three different light zones in the “PV Rooftop Garden” system (suitable species are marked with “x”). Table 5 gives an overview of the suitability of ornamental perennial plant species in the different light zones of the PV Rooftop Garden: Different species of _Hosta_ as well as _Hemerccallis liliuospodelus_, _Aster divaricatus_, and _Primula denticulata_ were suitable for all light zones. _Coreopsis lanccolata_ had good vitality in all zones and self-spread wildly across the entire planting bed. _Iris foetidissima_ (the only _Iris_ species suitable for semishading) successfully grew and flowered in all areas and the bright orange fruit added a great visual aspect in winter. Other species of _Iris_ are only recommended for sunny areas. _Campanula portenschlagiana_ showed good vitality in all light zones; however, their bloom and growth was reduced with less light. _Poligonatum humile_ was too small and not competitive and was overgrown, but _Poligonatum multiforum_ grew and flowered successfully in the semishaded and shaded light zones. The same effects were monitored for _Aruncus aethusifolia_, which did not survive in any zone, while the bigger form _Aruncus dioicus_ survived successfully in zone 3. _Salvia memorosa_ as well as _Sedum_ x _telepliium_ is recommended for the sunny zones. _Campanula lactiflora_ had a bad performance in all three zones. _Aurinia saxatile_ died in the shaded zones during the first year but also showed bad vitality in the sun as well.