Rehmannia elata
Newly planted in the Asian area is this striking and interesting herbaceous perennial from the Hubei and Shanxi provinces in China. Rehmannia elata is commonly known as the ‘Chinese foxglove’ because the tubular bell like flowers bear a resemblance to our native foxglove. The flowers are large, bright pink to red and flare open and outward showing yellow-spotted throats that crown the tall stems.
The flowers are prolific, starting in July they are long lasting and will repeat flower over the summer and into the autumn. Growing from rosettes of large ovate to heart shaped soft haired grey-green leaves that again, appear much like our native foxgloves, they provide a lush backdrop to the flowers.
Rehmannia elata will grow in a wide range of soils as long as they are well draining and will tolerate full sun and part shade. It requires a sheltered position but that can be south, east or west facing. The plant ultimately reaches 1 -1.5m in height with a spread of 0.5-1m.
It is an RHS AGM plant with designated H3 hardiness to -5C that puts it on the borderline of hardiness, however climate change is increasing the number of ‘half hardy’ plants growing well not just in Sheffield, but over much of northern England. Nevertheless, a protective layer of mulch in the autumn will help prevent drying winter winds and any frost.
The roots of the plant are notable, being thick, fleshy, and tuberous and can be quite large. These are both a source of propagation material and are renowned for their medicinal properties and cultural significance especially in traditional Chinese medicine.
Rehmannia elata is ecologically important with an ability to thrive in specific native habitats making it a significant component of the ecosystem, often growing in the understory of semi-shaded woodlands and grasslands. Here it benefits from dappled sunlight while avoiding extreme drying conditions. Its adaptability allows it to flourish in a range of altitudes, generally favouring elevations of 1,000 to 3,000 meters. The plant provides essential habitat and food for various pollinators, including bees and butterflies.
Of botanical note is that in 2016 a taxonomic naming revision placed Rehmannia sp.in an enlarged Orobanchaceae family, the Parasitic Broomrapes, making it one of the few genera within the family that do not have a parasitic habit on the roots of other plants.
The genus name honours Joseph Rehmann (1753-1831) German physician and botanist who settled in St. Petersburg
