Rehmannia, Chinese foxglove

Chinese foxglove- Rehmannia angulate or Rehmannia elata 

By Kim Willis These articles are copyrighted and may not be copied or used without the permission of the author.

I remember this lovely plant from my grandmother’s garden, and I remember she was proud of it for some reason, maybe because it wasn’t common or hardy in her growing zone.  It turns out it used to be grown more frequently in gardens until about the 1960’s and it’s a shame gardeners aren’t growing it more often now. It has been grown in western gardens since at least 1830. I was able to get a small plant from Select Seed this spring and I am very happy with the plant, which in a couple months is large and producing lots of flowers.

There are two scientific names floating around for the plant, Rehmannia elata is probably the most common. It’s called Chinese Foxglove (common name) because its native to China and the flowers somewhat resemble the common foxglove.  It’s related to Rehmanniae radix, an important herb in Chinese medicine.

Chinese foxglove is not related to the common garden foxglove many gardeners are familiar with. It has larger flowers and blooms much longer than regular foxglove.  The foliage stays green through summer and turns red in the fall in colder areas.  In zones 8 and above it’s evergreen and may bloom through the winter season.

This pretty plant has a basal rosette of foliage at first, then sending up blooming stalks with alternate leaves.  The leaves are rough textured with fine hairs and prominent veins.  They have an irregularly scalloped edge and grow up to 10 inches long.  Plants average 2-3 feet high with bloom stalks but can get to 5 feet in perfect conditions.  Plants have rhizomatous roots and spread quickly in good conditions.  My small plant has numerous daughter plants in it’s first year of growth.

The flowers of Chinese foxglove are tubular, with a flared lip of 3 fused petals and dangle downward.  They are about 3 inches long.  Most are a rosy, peachy pink with a yellow throat dotted with carmine.  Some nurseries have developed strains with deeper pink flowers and there is a rare white variety that’s hard to find.  It must be started by cuttings. The plants are free blooming, with stalks of flowers from spring to frost.  Bees and hummingbirds are attracted to the flowers.

Chinese foxglove likes rich, moist, well-drained soil but is tolerant of most soil types.  In the north it will grow in full sun if kept well-watered.  My plants receive nearly full sun.  Above zone 7 it should in partial or dappled shade. It’s biggest drawback, that I can see, is that it’s not hardy in zone 6 and lower and in zone 7 must be heavily mulched.  I intend to save seed and also to try and overwinter a young plant on the unheated porch.

Rehmania elata is fairly easy to start from seed and will bloom the first year from seed.  It should be started inside 8-10 weeks before your last frost.  The seeds need warm soil to germinate and should be lightly pressed into the soil because light is also needed for germination.  It’s important to keep the seeds evenly moist until germination.  Gardeners can find small plants from specialty nurseries on line but it’s uncommon to see them in many retail greenhouses in the northern states.

In zones 7 and higher where the plant is hardy it can spread quickly and make large clumps and some southern gardeners consider it invasive.  The plants can be divided and started from cuttings also.

In the US this plant has few insect or disease problems.  Slugs are said to eat it, although they don’t normally prefer plants with rough leaves like it has so I am skeptical.  I have seen Japanese beetles on the plants but have noticed little damage.

While Chinese foxglove is related to a commercially important herbal plant, little is known about this species herbal value.  It has toxic properties though and should not be experimented with.  I would consider it poisonous.