Silphium perfoliatum![RHS AGM](/assets/styles/images/icons/RHS-AGM--Small-Vert__web.svg)
cup plant
S. perfoliatum is an upright perennial to 2.5m tall, with paired, oval leaves joined around the stem, and branched sprays of bright yellow daisies 7-9cm wide, opening in late summer
![](https://apps.rhs.org.uk/plantselectorimages/detail/WSY0078586_6157.jpg)
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Size
Ultimate height
1.5–2.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Moist but well–drained, Well–drainedpH
Acid, Alkaline, NeutralColour & scent
Stem | Flower | Foliage | Fruit | |
Spring | Green | |||
---|---|---|---|---|
Summer | Yellow | Green | ||
Autumn | Yellow | Green | ||
Winter |
Position
- Full sun
- Partial shade
Aspect
West–facing or South–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical details
- Family
- Asteraceae
- Native to the UK
- No
- Foliage
- Deciduous
- Habit
- Bushy
- Genus
Silphium are robust herbaceous perennials with tall stems bearing simple leaves, aromatic when bruised, and loose clusters of yellow, daisy-like flowers in summer and early autumn
- Name status
Correct
- Plant range
- E N America
How to grow
Cultivation
An impressive plant suitable for the back of a border. It performs best when grown in full sun; in partial shady, or windy, sites it may require staking
Propagation
Propagate by seed or division
Suggested planting locations and garden types
- Architectural
- Cottage and informal garden
- Flower borders and beds
Pruning
Cut back after flowering; stems may optionally be left until shortly before new growth begins the following season
Pests
Generally pest-free
Diseases
Generally disease-free
Get involved
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