A truly lovely plant with large pink showy flowers that blooms from late spring until the frost. It is perfect for borders in dappled shade and full sun in higher latitudes. Blooms best in cooler temperatures so picking an area where it wont get too hot or can pick up a breeze is ideal. Not fussy about soil type but does like a well drained soil. Easy to grow it is a perennial but might not survive above zone 7 so grow it there as an annual. Blooms prolifically first year from seed. No garden should be without this lovely plant, looks really exotic.
Description of Chinese Foxglove (Rehmannia elata).
In spring sends out large semi oval shaped leaves of mid green with darker deep veins and irregular scalloped margin. Large rosettes of leaves then produce tall stems with large tubular flowers of pink or light purple with gold to orange centers. Flowers are borne on branching stalks which flower from the base of the stem towards the top. Flowers are large up to 2" across and 3" long and bloom from late spring until frost. The plant produces rhizomes which will overwinter and flower for many years if mulched and protected in colder zones.
What zone is it hardy to?
That depends on your source. It is certainly a perennial in zones 8, 9 and more. Zone 7 is unpredictable. It can overwinter if the weather is not too server but if its colder it will die off. We have had it overwinter in warm winters and vanish when its cold. The upshot is if you are zone 7 or lower then consider it as an annual and be prepared to reseed it every year. Once you have grown it once then you will want to grow it again its such a gorgeous plant with exotic flowers and it just blooms and blooms. Grows rapidly from seed and blooms in about 70 days from germination then it keeps going until the killing frost.
Location and Care of Chinese Foxglove (Rehmannia elata).
Prefers to have a reasonable amount of sunshine but since it will flower more prolifically at cooler temperatures some shade from the heat of the summer is recommended in Zones 8-11 more shade should be used, and area that gets dappled sun with through breezes to keep the plants cool should provide the best results. Somewhere that has full sun in the morning or evening, and shade from noon sun it best. For zones 7 and higher full sun all day is just fine.
Prefers a rich soil that is well drained. Recommend adding organic material such as compost to the soil before planting for the best results. Top dress with mulch over the winter to protect the plants. Take care not to over mulch and attract voles which love to eat the rhizomes.
Plants can grow to 2 feet wide and 3 feet tall so allow space when setting out plants. Water daily for best results using a soaker hose or drip irritation. Can tolerate watering once a week but flowers will not be as prolific.
May tend to flop over after a couple of months so might want to stake it. Mostly the older flower heads fall over and the newer ones stay upright so you still get lots of upright flowers. Its going to depend on how you want your plants to look.
We never stake ours but mostly ours are grown as annuals, when they do overwinter they are larger and stronger an more likely to need stakes.
Feeding with liquid fertilizer during the summer season will help keep plants strong and prolific.
In zones where it overwinters it will spread underground using runners and can be used as a really nice groundcover. It will however die back in winter. Great for flower borders and cut flowers.
Growing Chinese Foxglove (Rehmannia elata) from seed.
Chinese foxglove seeds are small so sowing indoors is recommended for best results. Plants can be sown outdoors after all danger of frost has past but seedlings may be overwhelmed by weeds.
Sow in good potting soil in small pots, plug trays or seed trays for best results. See general growing instructions - small seeds for best results. Germination can be from 15-30 days depending on temperature. Transplant out when plants have reached at least six inches of height and have been hardened before placing in desired location. Easy to germinate and grow. May easily self seed.
Medicinal uses of Chinese Foxglove (Rehmannia elata).
This plant is very similar to another Chinese foxglove (Rehmannia glutinosa) also known as Di Huang which has been used for centuries in Chinese herbal medicine and is considered one of the 50 fundamental herbs. Little is actually reported about Rehmannia elata and very little that is definitive. A few sources state this plant can be used instead of R. glutinosa but I don't feel they are reliable. The few Chinese sources state briefly that Rehmannia elata does not have the same properties and is not used. There are no research papers to date so the best conclusion is that this plant is NOT used medicinally only for its beautiful flowers. Sadly R. glutinosa is much more difficult to grow and very hard to obtain. (we are working on it).