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Herbaceous PerennialBogs

Asclepias incarnata

swamp milkweed

A thick-stemmed perennial with dense stems and narrow, mid-green leaves up to 15cm long. Clusters of dark purplish-pink flowers are produced from the upper part of the stems from mid-summer to early autumn, followed by narrow, upright seed pods up to 7cm long, green at first then turning pale brown before splitting to release the seeds with their parachutes

Other common names
water nerveroot
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Size
Ultimate height
1–1.5 metres
Time to ultimate height
2–5 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Clay
Loam
Sand
Moisture
Moist but well–drained, Poorly–drained
pH
Acid, Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Pink Green
Autumn Pink Green Green Brown
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Sheltered
Hardiness
H4
Botanical details
Family
Apocynaceae
Native to GB / Ireland
No
Foliage
Deciduous
Habit
Bushy
Potentially harmful
Harmful if eaten. Wear gloves and other protective equipment when handling
Genus

Asclepias can be evergreen or deciduous perennials or subshrubs, with simple, entire leaves and umbel-like clusters of small, distinctively shaped flowers followed by paired fruits containing seeds embedded in silky fibres

Name status

Correct

Plant range
NE & SE USA

How to grow

Cultivation

Grow outdoors in moist, fertile, loamy soil in full sun. Will thrive near a pond or stream

Propagation

Propagate by seed or by division, or root basal cuttings in spring

Suggested planting locations and garden types
  • Cottage and informal garden
  • Prairie planting
Pruning

No pruning required

Pests

Generally pest-free

Diseases

Generally disease-free

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