Flowering Plants Shimmering border at Pensthorpe Posted by Catharine Howard on July 31, 2014May 25, 2017 Or Oudolf does it again. Digitalis ferruginea and echinacea. There was a time, way back in the blurred mist of yesteryear, when the flower borders were losing it for colour and interest by now. These two will go on and on. A brilliant co-planting.