Scientific: Senna artemisioides subsp. filifolia (formerly Cassia nemophila)
Common: threadleaf senna (formerly threadleaf cassia)
Family: Fabaceae (Leguminosae)
Origin: Southwestern Australia
Pronounciation: SIN-na ar-te-mi-see-OYE-deez fil-i-FOL-ee-a
Hardiness zones
Sunset 12-24
USDA 9-11
Landscape Use: Informal hedge, background, screen, brief early spring flowering accent.
Form & Character: Billowy, rounded, open, creating feeling of distance.
Growth Habit: Evergreen, woody, broadleaf (leaflets narrow) perennial shrub, vigorous, upright and open to 15 feet in height will equal spread.
Foliage/Texture: Medium to dark green, four leaflets per leaf, leaflets are narrow, linear; fine texture.
Flowers & Fruits: Lemon yellow pea flowers in late winter to early spring at same time as Senna artemisiodes xartemisioides, but not fragrant, dark brown bean pod fruit in late Spring to Summer are ugly.
Seasonal Color: Yellow in early spring for about two weeks.
Temperature: Hardy to 18oF.
Light: Full sun
Soil: Well drained
Watering: Drought tolerant, supplemental water will increase rate of growth.
Pruning: Prune only as necessary only after flowering in April. Severe renewal pruning after flowering will rejuvenate, but make sure to leave some foliage or else the plant have a difficult time regrowing. Frequent shearing will impact spring floral display as this plant sets flower buds in August.
Propagation: Seed, hot water soak.
Disease and Pests: Root rot if soil is poorly drained
Additional comments: Threadleaf senna is slightly more cold hardy than feathery senna. As with other large senna, allow adequate space for growth. Do not use where frequent pruning will be needed to control growth as this will compromise flowering potential.
