Heester concept Cornus alba kesselringii Cornus alba Siberica Cornus stolonifera flaviramea Deutzia scabra Forsythia intermedia Spectabiles Philadelphus virginal Potentilla fruticosa Ribes sanquineum ‘King Edward V11” Spiraea bumalda ‘Anthony Waterer Spiraea cineria ‘Grefsheim’ Spiraea vanhouttei Weigelia hybr. ‘Bristol Ruby’