Foxglove: Another Pleistocene Survivor

Poison lurks around the corner.  A half acre stand of yellow foxglove grows on land two lots down from my house where an abandoned trailer sits behind hundred year old laurel oaks.  The trailer was owned by a bachelor  before he died of a heart attack on a trip to Vegas a few years ago.  Yellow foxglove (Digitalis grandiflora) is poisonous to people and animals, including both carnivores and herbivores.   Ingestion causes loss of appetite, nausea, and a dangerously lowered heart rate that can cause death.  Drug-makers manufacture medicine from this plant, and it’s used to control the irregular hearbeats suffered by patients in congestive heart failure.

Up close views of foxglove plants.

Part of a stand of foxglove.

Foxglove was probably a common plant during the Pleistocene.  It thrives in open oak glades and prefers disturbed and burned over areas.  An old pine tree in my yard exhibits evidence of a light brush fire in my neighborhood, perhaps 30-40 years ago before houses were built here.  Foxglove also grows well in acidic soils as does low bush blueberry which grows within this patch as an associate and also likes burned over areas.

Lowbush blueberry plant growing in association with foxglove.  Both like burned over areas with acidic soil.

During the Pleistocene light brush fires, frequent in both arid and rainy climate phases, shaped the environment along with the large herds of herbivores which consumed and destroyed many succulent plants but avoided poisonous foxglove.  Foxglove would have grown with grass, which can survive grazing because their taproots remain safe underground, and blueberry which also can resprout from suckers.  All three are tough plants, surviving on this lot, despite sandy acidic soils and extreme drought and heat.  Many a Pleistocene landscape would have been dominated by these three.

Foxglove should please flower gardeners–with no maintenance, this patch in the abovementioned lot has been continuously blooming for three months, since May.

Foxglove does require the presence of oak trees, and they are restricted to forest edges and open woodlands.  They are parasitic feeders; their roots latch on to the roots of oaks and that’s how they absorb nutrients.  False foxgloves, members of the figwort family, are close relatives of the true foxgloves, and they too are parasitic feeders.  In my opinion, though the flowers are similar to those of true foxgloves, the leaves are not.

Eolian sand dunes, formed throughout the southeast during Ice Age droughts when windborne river sand accumulated, were another ideal habitat for foxglove which could grow with scrub oaks and grass on these sparsely vegetated areas.

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