Longleaf Milkweed

Asclepias longifolia

Native to:
United States

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Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Apocynaceae
Genus:
Asclepias
Species:
Asclepias longifolia
USDA Symbol:
ASLO

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Forb/herb
Height:
120 cm
Light Requirements:
Full Sun
Drought Tolerance:
Low
Bloom Months:
may,jun,jul,aug
Bloom Colors:
white, cream, greenish-white

Wildlife Benefits

Bees:
★☆☆☆☆ Documented bee visitation (GBIF)
Butterflies & Moths:
★☆☆☆☆ Documented Lepidoptera association (GBIF)
Caterpillars:
★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)

Keystone Species Ranking

Caterpillar Keystone:
★★☆☆☆ Butterfly & moth species supported by this genus (NWF)

Host Plant for Caterpillars

⚠️Monarch butterfly (Danaus plexippus)

Garden & Ecology Notes

Wildlife Value:
bees, butterflies, Monarch butterflies
Deer Resistant:
Yes
Fragrant:
Yes
Fire Ecology:
Fire adapted — tolerates or benefits from fire
Fire Notes:
Resprouts vigorously from rhizomes after fire. Fire helps maintain open wetland habitat and reduces woody encroachment in native wet prairies.

Soil Requirements

Soil Type:
sandy, acidic, nutrient-poor soil
pH:
5.5 - 7.0 (slightly acidic to neutral)
Drainage:
excellent drainage required
Moisture:
consistently moist
Notes:
prefers open, sunny habitats like pine savannas

Propagation & Germination

Stratification:
Cold/moist stratification required — 30–60 days
Germination Time:
7–21 days
Notes:
Seeds require light for germination. Best sown on surface and kept consistently moist at 70-75°F after cold stratification.

The above propagation data sourced from Claude AI

Pre-treatment: Cold-moist stratification for 30 days at 1–5°C (34–41°F).; then Scarify, then cold-moist stratify for 60 days.

Source: Claude AI

ORGHPS Germination Guide: Should not need chilling

Source: Ontario Rock Garden & Hardy Plant Society