Digitalis grandiflora (Yellow Foxglove)

Plant Info
Also known as:
Genus:Digitalis
Family:Plantaginaceae (Plantain)
Life cycle:biennial, perennial
Origin:Europe, Asia
Status:
  • Weedy
Habitat:part shade, sun; disturbed soil; roadsides, fields, waste places, gardens, thickets
Bloom season:July - August
Plant height:20 to 40 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: tubular Cluster type: raceme

[photo of flowers] Nodding flowers are in an elongating spike-like raceme at the top of the plant, blooming from the bottom of the cluster first and all more or less arranged on 1 side of the stem. Individual flowers are up to about 2 inches long and ¾ inch wide with a creamy yellow funnel to bell-shaped tube and short triangular or rounded lobes around the mouth. Brownish lines or spots dot the inside of the tube with scattered hairs near the mouth. A few stamens are just inside the tube at the top of the mouth.

[photo of calyx and bracts] Around the base of the flower is a green calyx with 5 short linear lobes. At the base of the short flower stalk is a leaf-like bract. The calyx, stalks, bracts and the outer surface of the flowers are all covered in short glandular hairs.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are alternate, mostly lance-elliptic, 4 to 8 inches long, up to 1½ inches wide, stalkless, tapering to a pointed tip. Edges are finely serrated with tiny gland-tipped teeth. Leaves become smaller as they ascend the stem.

[photo of leaf and mid-stem hairs] The upper leaf surface is hairless, the lower variously hairy. Stems are single, unbranched, variously hairy with a mix of glandular and non-glandular hairs, the upper stem into the flower cluster more densely covered in short glandular hairs.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is an oval to tear-drop shaped capsule 1/3 to ½ inch long containing numerous brown to black seeds about 1 mm long. The capsule splits open lengthwise, dropping much of its seed near the mother plant.

Notes:

Yellow Foxglove, native to parts of Europe and Asia, has long been available in the garden trade and occasionally escapes cultivation. To date, in Minnesota it has only been reported in St. Louis County. One roadside population near Hoyt Lakes is described as “Appears to have spread into woods at least 200 ft (cannot see beyond this far) on both sides of road.” That was 15 years ago; it would be interesting to see if it was eradicated or allowed to continue spreading.

Yellow Foxglove should not be confused with any other species. The large creamy-yellow funnel-shaped flowers are distinctive; the upper stem into the flower cluster is densely covered in short gland-tipped hairs; leaves are hairless on the upper surface and hairy beneath and edged with tiny gland-tipped teeth; fruit is a capsule that splits open lengthwise. Like all Digitalis species, it is poisonous. If you see it in the wild, we suggest getting rid of it before it spreads.

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More photos

Photos by K. Chayka and Peter M. Dziuk taken along County Rd B near Land O' Lakes, Wisconsin.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Katie - West Lakeland
on: 2019-10-21 10:04:52

Spotted a small population of what we assumed was either this species or lutea at the edge of woodlot that had been cleared the year prior of Buckthorn. It was later in the fall so only the dried stalks were present. The homeowners had not planted it, but say that it grows back every year and has a yellow flower. It doesn't seem to be spreading, but is in a location that made me think it escaped a flower bed long ago. The initial sighting was fall 2017, saw leaves spring 2018, haven't been back since.

Posted by: K. Chayka
on: 2019-10-21 13:09:30

According to FNA, some differences between Digitalis grandiflora and D. lutea are: the latter is mostly hairless all over, only a few hairs on some leaf veins and sparse glandular hairs in the flower clusters, plus flowers half the size (or smaller). The hairs on D. grandiflora should persist so it should still be possible to distinguish them late in the season when flowers are gone.

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