Roughstem Rosinweed (Silphium radula)

Roughstem Rosinweed

Also known as: Starry Rosinweed

This perennial, the roughstem Rosinweed or Silphium radula, is a member of the aster or sunflower family. It grows upright and is topped by yellowish-green blossoms, making it a popular border plant. It prefers dry, poor soil and will topple over if the soil is too rich or wet.

Scientific classification

Species

Roughstem Rosinweed (Silphium radula)

Asters bellflowers fanflowers and allies

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91 cm to 1.8 m

Plant Height

60 cm to 90 cm

Spread

2.5 cm to 8 cm

Flower Size

Brown

Flower Color

Deciduous

Leaf type

10 - 35 ℃

Ideal Temperature

Images of Roughstem Rosinweed

Care Guide for Roughstem Rosinweed

Every week

Water

Full sun

Sunlight

10 - 35 ℃

Ideal Temperature

Water: Originating from dry environments, roughstem Rosinweed is moderately drought-tolerant, thriving on a weekly watering schedule. It balances occasional moisture with its ability to withstand dry conditions, making it ideal for outdoor cultivation in water-conserving garden regions.

Fertilize: To ensure vibrant growth of roughstem Rosinweed, use balanced fertilizers and switch to high phosphorus during flowering. Apply moderately at the season's start and bi-monthly, adjusting for size and soil. Fertilizing frequency should decrease in winter and increase in spring, enhancing vitality and flower quality.

Pruning: Roughstem Rosinweed requires selective pruning in early to late spring to encourage healthy growth and flowering. Remove dead stems, thin dense areas for air circulation, and maintain a natural shape. This timing enhances resilience, vigor, and disease resistance, supporting vibrant blooms in the garden.

Propagation: Roughstem Rosinweed is primarily propagated by sowing fresh seeds in well-draining soil. Ensure direct sunlight for germination and maintain consistent moisture without waterlogging. Regularly monitor for pests and diseases to support healthy seedling growth.

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Images of Roughstem Rosinweed

Care Guide for Roughstem Rosinweed

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