Woolly Locoweed

Woolly Locoweed: A Beautiful but Cautionary Native Plant

Meet woolly locoweed (Astragalus mollissimus var. mollissimus), a perennial native that’s both captivating and controversial in the gardening world. This purple-flowered beauty has a story that every gardener should know before deciding whether to welcome it into their landscape.

What is Woolly Locoweed?

Woolly locoweed is a native perennial that calls the American Great Plains and Southwest home. You’ll find this hardy plant naturally growing across Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. As a true native, it’s perfectly adapted to the challenging conditions of these regions.

The plant gets its woolly name from its fine-textured, soft foliage, while locoweed hints at a more serious characteristic we’ll discuss shortly. Growing in a decumbent (low-spreading) form, woolly locoweed typically reaches about 2 feet in height and spreads along the ground with a single crown growth pattern.

The Beauty and the Beast

Let’s start with the beautiful side. Woolly locoweed offers genuine aesthetic appeal:

• Showy purple flowers that bloom in late spring
• Attractive, fine-textured green foliage
• Excellent drought tolerance once established
• Moderate growth rate that won’t overwhelm your garden
• Natural nitrogen-fixing ability that enriches soil

The flowers are particularly lovely, creating purple drifts across the landscape when conditions are right. As a member of the legume family, this plant also helps improve soil fertility through nitrogen fixation.

The Critical Concern: Toxicity

Here’s where we need to have a serious conversation. Woolly locoweed contains alkaloids that are toxic to livestock, particularly cattle, horses, and sheep. The plant’s common name locoweed comes from the erratic behavior (loco means crazy in Spanish) that animals exhibit when they consume it over time.

While this toxicity primarily affects grazing animals, it’s something every gardener should consider, especially if you:

• Have livestock or neighbors with livestock
• Live in areas where animals might graze
• Have pets that tend to nibble on plants

Growing Conditions: Tough as Nails

If you decide that woolly locoweed is right for your situation, you’ll find it remarkably easy to grow. This plant is practically built for challenging conditions:

• Soil: Adapts to coarse, medium, and fine-textured soils
• pH: Tolerates a range from 5.6 to 7.5
• Water: Extremely drought tolerant once established (12-30 inches annual precipitation)
• Sun: Requires full sun (shade intolerant)
• Temperature: Hardy to approximately USDA zones 4-8 (tolerates -28°F)
• Fertility: Low fertility requirements

Planting and Care Tips

Woolly locoweed is typically grown from seed, as it’s not commonly available through commercial nurseries (usually available by contracting only). Here’s how to succeed:

• Seeding: Direct sow seeds in fall or early spring
• Patience required: Seeds have low seedling vigor, so don’t expect quick establishment
• Minimal care: Once established, this plant needs very little attention
• No pruning needed: The plant doesn’t resprout after cutting
• Frost free days: Needs at least 100 frost-free days per year

Wildlife and Pollinator Benefits

The purple flowers provide nectar for native bees and other pollinators during the late spring blooming period. However, the plant produces seeds with moderate abundance that persist only briefly, so it’s not a major food source for wildlife.

Is Woolly Locoweed Right for Your Garden?

This native plant works best in specific situations:

Consider woolly locoweed if you:

• Are creating a native prairie or xeriscape garden
• Live in its native range and want authentic local flora
• Need extremely drought-tolerant groundcover
• Have no livestock or grazing concerns in your area

Skip woolly locoweed if you:

• Have livestock or live near grazing areas
• Have pets that frequently eat plants
• Prefer low-maintenance plants with quick establishment
• Want a plant that provides significant wildlife food

The Bottom Line

Woolly locoweed represents one of those fascinating native plants that comes with both gifts and responsibilities. Its drought tolerance and native credentials are impressive, but its toxicity to animals requires careful consideration. If you’re in its native range and can safely accommodate its needs, it can be a valuable addition to a native plant collection. However, for most home gardeners, there are safer native alternatives that provide similar benefits without the livestock concerns.

Remember, being native doesn’t automatically make a plant perfect for every garden situation. Sometimes the most responsible choice is appreciating a plant in its wild habitat while choosing safer alternatives for our designed landscapes.