Maryland Senna

senna marilandica

Maryland Senna (Senna marilandica) is a charming native perennial in the pea family, Fabaceae, bringing a splash of cheerful yellow to meadows, open woodlands, and roadsides across the eastern and central United States. This robust plant is valued not only for its attractive late-summer blooms but also for its significant ecological contributions. It serves as a vital larval host plant for several butterfly species, including the Cloudless Sulphur, and its flowers provide abundant nectar for a variety of native bees. Beyond its beauty, Maryland Senna plays a crucial role in soil health through nitrogen fixation, making it an excellent candidate for ecological restoration projects and native plant gardens. Its distinctive seed pods, appearing after flowering, add further interest through the fall and winter.

Habitat: This species thrives in open, sunny to partially shaded environments, commonly found in moist to dry-mesic soils of open woodlands, woodland edges, meadows, fields, roadsides, and disturbed areas.

Appearance

Maryland Senna is characterized by its bright, sunny yellow flowers, typically blooming from mid-summer into early fall. The flowers are arranged in short, axillary clusters and have five distinct petals, often with a slightly irregular shape. Its foliage consists of pinnately compound leaves, each composed of 6 to 10 pairs of oblong to lance-shaped leaflets that are smooth and dark green. The plant grows as an upright, herbaceous perennial, reaching heights of 90 to 180 centimeters (3 to 6 feet). After the flowers fade, long, flat, dark brown to black seed pods develop, adding to its visual appeal and aiding in identification.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderFabalesFamilyFabaceaeGenusSenna

Maryland Senna

Interesting facts

Its seed pods, resembling flattened green beans, turn dark brown to black as they mature and persist on the plant into winter, providing visual interest.

Maryland Senna is a popular choice for native plant gardens and pollinator gardens due to its low maintenance, drought tolerance, and ecological benefits.

The genus name 'Senna' comes from the Arabic word 'sana', referring to a plant whose leaves and pods have purgative properties, though this specific species is not widely used medicinally.

Unlike many plants, Maryland Senna requires 'buzz pollination' (sonication) where bees vibrate their flight muscles to release pollen from specialized anthers.

Special abilities

Maryland Senna, like many legumes, forms a symbiotic relationship with soil bacteria (Rhizobia) in its root nodules. These bacteria convert atmospheric nitrogen into a form usable by the plant, enriching the soil for itself and surrounding vegetation.

Its bright yellow flowers are a significant source of nectar and pollen, attracting a wide array of native pollinators, particularly long-tongued bees such as bumblebees and carpenter bees. It also features 'poricidal anthers' which require buzz pollination.

The foliage of Maryland Senna serves as a critical food source for the caterpillars of several butterfly species, notably the Cloudless Sulphur (Phoebis sennae) and the Sleepy Orange (Eurema nicippe), supporting their life cycles.

Measurements & details

Length: 90-180 cm
Weight: 0.5-2.5 kg
Lifespan: 3-10 years

Diet & Feeding

As a photosynthetic organism, Maryland Senna produces its own food by converting light energy into chemical energy. It absorbs water and essential mineral nutrients from the soil, and carbon dioxide from the air to fuel its growth and metabolic processes.

Primary Foods

Sunlight
Carbon Dioxide
Water
Nitrogen (from soil)
Phosphorus (from soil)
Potassium (from soil)

Ecological connections

larval host

Cloudless Sulphur Butterfly

Phoebis sennae

The caterpillars feed on the leaves of Maryland Senna.

mutualism

Bumblebee

Bombus spp.

They collect nectar and pollen from the flowers, facilitating cross-pollination.

eaten by

White-tailed Deer

Odocoileus virginianus

Grazing animals may browse on the foliage, especially younger plants.

mutualism

Rhizobia Bacteria

Rhizobium spp.

These bacteria live in root nodules and convert atmospheric nitrogen into usable forms for the plant.

Traits

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Also known as

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Maryland Senna?

The easiest way to identify Maryland Senna is to use the Snappit nature identifier app.

How long is Maryland Senna?

90-180 cm

How much does Maryland Senna weigh?

0.5-2.5 kg

How long does Maryland Senna live?

3-10 years

What does Maryland Senna eat?

Where is Maryland Senna usually found?

This species thrives in open, sunny to partially shaded environments, commonly found in moist to dry-mesic soils of open woodlands, woodland edges, meadows, fields, roadsides, and disturbed areas.