North America Native Plant

Manystem Pea

Botanical name: Lathyrus polymorphus polymorphus var. hapemanii

USDA symbol: LAPOH

Life cycle: perennial

Habit: vine

Native status: Native to the lower 48 states  

Manystem Pea: A Mysterious Native Wildflower Worth Understanding If you’ve stumbled across the name manystem pea in your native plant research, you’re likely wondering what exactly this plant is and whether it belongs in your garden. The botanical name Lathyrus polymorphus polymorphus var. hapemanii might sound intimidating, but this native ...

Manystem Pea: A Mysterious Native Wildflower Worth Understanding

If you’ve stumbled across the name manystem pea in your native plant research, you’re likely wondering what exactly this plant is and whether it belongs in your garden. The botanical name Lathyrus polymorphus polymorphus var. hapemanii might sound intimidating, but this native wildflower has an interesting story – even if much of that story remains shrouded in mystery.

What is Manystem Pea?

Manystem pea is a perennial forb herb, meaning it’s a non-woody plant that dies back to the ground each winter and returns the following spring. As a member of the pea family, it shares characteristics with other familiar garden legumes, though this particular variety is quite specialized in its distribution and requirements.

Unlike shrubs or trees, manystem pea lacks significant woody tissue and maintains its growing points (buds) at or below ground level, helping it survive harsh winters and return reliably each growing season.

Native Status and Where It Grows

The good news for native plant enthusiasts is that manystem pea is indeed native to the lower 48 United States. However, its distribution is remarkably limited – this variety appears to be found only in Nebraska, making it a true regional specialty.

This extremely limited distribution is one of the factors that makes manystem pea such an enigmatic plant. While many native wildflowers have broad ranges spanning multiple states or regions, this particular variety seems to have found its perfect niche in a very specific area.

The Challenge of Growing Manystem Pea

Here’s where things get tricky for gardeners: there’s remarkably little documented information about growing manystem pea. This isn’t necessarily because it’s difficult to grow, but rather because it’s so geographically limited that few gardeners and researchers have had the opportunity to study its cultivation requirements.

What we don’t know includes:

  • Specific soil preferences
  • Water requirements
  • Sun or shade tolerance
  • USDA hardiness zones
  • Propagation methods
  • Mature size and growth rate
  • Pollinator relationships

Should You Try to Grow It?

The limited information available makes it challenging to recommend manystem pea for most home gardens. If you’re gardening outside of Nebraska, this plant is likely not naturally suited to your local conditions. Even within Nebraska, the specific growing requirements remain largely undocumented.

For most gardeners interested in native peas, there are better-documented alternatives that offer similar benefits with known growing requirements. Consider exploring other native Lathyrus species that are well-suited to your region and have established cultivation practices.

Better Native Pea Alternatives

If you’re drawn to native peas for their nitrogen-fixing abilities, attractive flowers, or wildlife benefits, consider these well-documented alternatives:

  • Wild bergamot pea (if available in your region)
  • Beach pea (for coastal areas)
  • Other regional Lathyrus species native to your area

Your local native plant society or extension office can help you identify which native pea species are best suited to your specific location and garden conditions.

The Value of Plant Mysteries

While manystem pea might not be the easiest addition to your garden, it serves as a fascinating reminder of how much we still don’t know about our native flora. Plants like this highlight the importance of botanical research and conservation efforts to document and protect our regional plant diversity.

If you’re a Nebraska gardener who encounters this plant in the wild, consider yourself lucky to witness a true botanical rarity. Just remember to observe and appreciate without disturbing – rare plants like manystem pea deserve our protection and respect.

Manystem Pea

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Rosidae

Order

Fabales

Family

Fabaceae Lindl. - Pea family

Genus

Lathyrus L. - pea

Species

Lathyrus polymorphus Nutt. - manystem pea

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA