PROTECTING WISCONSIN'S BIODIVERSITY

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Scientific Name	Common Name	Global Rank	State Rank	Federal Status	WI Status

Hairy Wild Petunia (Ruellia humilis)

State Status: END

Federal Status: none

State Rank: S2

Global Rank: G5

Photo by Julie Robson

Counties with Mapped NHI Occurrences

Hairy Wild Petunia (Ruellia humilis), a Wisconsin Endangered plant, is found in prairies and upland oak woods. Blooming occurs late-May through early-October, fruiting late-June through mid-October. The optimal identification period for this species is late-May through early-October.

Synonyms:

Ruellia humilis var. depauperata, Ruellia humilis var. longiflora

Identification

Hairy wild petunia is an erect forb, 2-6dm tall, with flowers in sessile or subsessile, crowded cymose clusters from the axils of several upper leaves. Calyx lobes are less than 1mm wide, corolla are blue-lavender, 3-7cm, funnelform, and 5-lobed, 4 stamens are weakly united in pairs toward the base, the lower pair is somewhat longer. Fruits are smooth. Leaves are opposite, sessile or subsessile, 3-8cm long, acute to very obtuse, and the margins are hairy.

Distinguishing Characteristics and Similar Species

It can be distinguished from look-alikes by its profusion of hairs, sessile or subsessile leaves, narrowly linear calyx lobes, and long funnelform lavender flowers.

Phenology and Reproduction

Phenology

Blooming occurs late-May through early-October; fruiting late-June through mid-October.

Life Cycle, Optimum Time to Identify

Perennial. The optimal identification period for this species is late-May through early-October.

Ecology and Associated Species

Associated species include Andropogon scoparius, Euphorbia corollata, Lithospermum canescens, Petalostemum purpureum, Ratibida pinnata, Lespedeza capitata, and Helianthus occidentalis.

Habitat

Hairy wild petunia is found in prairies, oak openings, and upland oak woods.

Avoidance Measures and Management Guidance

Avoidance Measures

Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.

Avoid broadcast spraying of herbicides and use care with spot spraying.

Management Guidance

Prescribed burns and/or brushing may be beneficial, dependent on local site conditions and burn frequency. Rotational burns with annual unburned refugia may be preferred.

Maintain and restore open habitat through selective clearing and brushing.

Wildlife Action Plan

Associated Natural Communities and Ecological Landscapes

Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Issues/Threats and Conservation Actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.

PROTECTING WISCONSIN'S BIODIVERSITY

Hairy Wild Petunia (Ruellia humilis)

Rare Species & Natural Communities

Additional Resources

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