White snakeroot (Ageratina altissima) Seeds
In September and October, the broad, dark green upright stems of this species are topped with bright-white clusters of small flowers attracting fall pollinators. A prolific self-sower; cut back after bloom in a small garden. This is an excellent species to plant after invasive species have been removed in a woodland.
Native to Maine: Yes
Growing conditions: Shade to part sun in moist to dry soil
Natural habitat: Deciduous woodland understories, shady roadside edges, and disturbed areas
Grows up to: 2'
Blooms: In early autumn
Pairs well with: Blue lobelia and blue wood-aster
Seeds per packet: 50-100
Germination Code(s): B and C
These seeds require a cold period to germinate - a minimum of 60 days below 40°F in moist soil (or sand or vermiculite). Sow outdoors in pots, on the soil surface and leave uncovered, November through March. A great species for beginner seed-sowers.
Each seed package carries a specific germination code along with the plant description. These codes indicate specific sowing instructions.
- A Seeds can be sown outdoors in fall or early spring.
- B Seeds need a winter or cold period to germinate. Sow outdoors in fall or winter.
- C Seeds need light to germinate; sow on soil surface and leave uncovered.
- D Seeds need alternating cycles of warm-to-cold-to-warm to germinate. They can be sown either outdoors in spring or summer and will germinate the following year or in a flat in a warm place for 3 months, then moved to a refrigerator for 2 months, then moved outside in the early summer warmth.
- E Seeds can not be allowed to dry out. Sow immediately.
- F Seeds take two years to germinate. Sow outside in the fall or winter and look for germination in the second spring. A shady location prevents the flats from rapid drying and reduces weeding
- G Large seeds should be soaked overnight in water.
- FERN: Sow spores in a warm bright location in a sealed container and keep moist. Directions enclosed with package. Challenging.
If you have specific questions about seeds and germination guidelines please contact us at email@example.com.
All seeds can be sown and placed outdoors in fall or winter bypassing the need for an artificial indoor cold stratification (refrigerator) required for some species when planted in spring. This is the simplest method. See How to Grow Natives From Seed for detailed instructions.