Groundcherries (Physalis spp.)
Nightshade Family (Solanaceae)
Origin and Distribution:
Some groundcherries are perennials that are natives of eastern and central North America and among these, CLAMMY GROUNDCHERRY (Physalis heterophylla) and SMOOTH GROUNDCHERRY (Physalis subglabrata) occur throughout Ohio. The species grow in cultivated and reduced-tillage agronomic fields as well as pastures, old fields, open woods, roadsides, and waste areas. Groundcherries prefer well-drained conditions and it is not uncommon to find either of these species growing in stony, gravelly, or other poor soils.
Along with other close relatives, groundcherries have bell-shaped flowers and their fruits are berries resembling miniature tomatoes. Traits identifying perennial groundcherries are deeply-penetrating roots, yellow flowers with purplish centers, and fleshy berries enclosed in an inflated, bladder-like body that looks similar to a paper lantern. If the foliage is covered with sticky hairs, leaves are heart-shaped, and berries are yellow then the plant is probably CLAMMY GROUNDCHERRY while SMOOTH GROUNDCHERRY is more or less hairless and has diamond-shaped leaves and reddish berries. Both species reproduce by seeds and creeping roots.
Roots are deeply penetrating and widely spreading.
Seedlings and Shoots:
Young groundcherry plants have hairy stems and leaves with hairs on the upper surface, edge, and along veins on the lower surface. Foliage emits an unpleasant nightshade odor when bruised.
Stems are 1 to 3 feet tall, hollow, ridged, and often woody. Stems grow upright at first but later branch resulting in a bushy plant with a spreading top. Located at each fork in the stem are a long stalk (petiole) attached to a single leaf and another stalk that is curved with a solitary flower dangling at the end. CLAMMY GROUNDCHERRY stems are covered with sticky hairs. Young stems of SMOOTH GROUNDCHERRY may be hairy but older stems are hairless.
Leaves are alternate (1 leaf per node), 1 to 4 inches long, and coarse. Leaves of CLAMMY GROUNDCHERRY are heart-shaped and have a round base while those of SMOOTH GROUNDCHERRY are diamond-shaped with a base that tapers into a long petiole. Edges may be either smooth or irregularly toothed.
Flowers consist of 5 fused petals that are greenish-yellow with a violet-spotted center. Flowers are in the shape of a bell and are about 3/4 inch long. Flowers are usually solitary and suspended from a curved stalk attached to the stem at the leaf axils.
Fruits and Seeds:
Fruit is a fleshy 2-celled berry enclosed in a 5-sided, bladder-like pod that looks similar to a paper lantern. Berries of CLAMMY GROUNDCHERRY are yellow while those of SMOOTH GROUNDCHERRY are orange or red-purple. Fruits contain many flat, kidney-shaped seeds that are less than 1/10 inch in diameter and light yellow.
Several other annual and perennial nightshade species (Solanum spp.) have an appearance similar to that of groundcherries except their flowers are white or purple and clustered while groundcherry flowers are yellow and solitary.
Plants flower from June to September. There are reports of groundcherries producing up to 30,000 seeds per plant. If fragmented by tillage or other similar disturbance, roots can give rise to new plants. A study found that new plants emerged from root fragments as short as 1 inch, and even more plants emerged from 4-inch-long fragments, but fragments left on the soil surface generally did not survive. Groundcherries cause indirect crop damage by hosting diseases and viruses of alfalfa, lettuce, tobacco, pepper, and potato and serving as an alternate host for several species of root knot nematodes. Tobacco budworm has been observed feeding on clammy groundcherry. Groundcherry species are reported to be relatively tolerant of 2,4-D.
Leaves and unripe fruits of groundcherries are poisonous and even fatal if ingested by humans. However, ripe fruits are not as toxic and can be made into jellies, jams, and sauces. Alkaloids from groundcherry plants are suspected to be poisonous to cattle, and there are reports that sheep and other animals were poisoned as the result of eating foliage and unripe berries. However, the plant is only toxic if ingested in large amounts and animals generally avoid eating groundcherries unless more palatable forage is not available, so poisonings are rare.
Facts and Folklore:
The genus name 'Physalisa', is from the Greek 'Physa' meaning 'bladder' and refers to the inflated papery husk surrounding groundcherry fruit.
Tomatillo or 'Mexican tomato' is a cultivated groundcherry.