Overview
Epilobium angustifolium 'Isobel' is a garden plant in the genus Epilobium, part of the Onagraceae family. It typically grows around 2.0 m tall. Epilobium angustifolium 'Isobel' grows best in full sun, and tolerates most soils. Its UK hardiness is rated H7.
About
Epilobium angustifolium 'Isobel' is a tall herbaceous perennial reaching about 2.0 m, notable for upright stems bearing racemes of magenta-pink flowers. It flowers from June to September. Plant in full sun in a well-drained soil; it tolerates sandy, loamy or clay soils if drainage is adequate. It carries the hardiness rating H7, meaning it is fully hardy across the UK.
Wikipedia contributors, CC BY-SA 4.0 — Chamaenerion angustifolium
About the genus
Epilobium is a genus of flowering plants in the family Onagraceae, containing about 197 species. The genus has a worldwide distribution. It is most prevalent in the subarctic, temperate and subantarctic regions, whereas in the subtropics and tropics Epilobium species are restricted to the cool montane biomes, such as the New Guinea Highlands.
Wikipedia contributors, "Epilobium", CC BY-SA 4.0 — Epilobium
In the garden
Epilobium angustifolium 'Isobel' belongs to the Onagraceae and is the cultivated form of the plant commonly called fireweed; it is native across temperate parts of the Northern Hemisphere. Flowering spikes carry magenta to pink blooms through June to September and the flower heads are typically a few centimetres across, producing an upright, elongating inflorescence above the foliage. Give 'Isobel' a sunny situation and you will get best flowering: plant it in full sun in sandy, loamy or clay soils, provided they are well-drained or moist but well-drained. The cultivar grows to around 2.0 m and copes with a wide range of soil textures so long as water does not sit at the roots. It is rated H7 (fully hardy) in the UK and corresponds to USDA zones 3–7, so it tolerates severe winter cold where winters are not subject to prolonged waterlogging. Use the plant at the rear of a herbaceous border where its height lifts the summer display, or in naturalistic groups where tall flower spikes are wanted. Expect the magenta-pink racemes to stand clear of the foliage from mid summer into early autumn, showing the plant at its full height and value in the garden.
Growing conditions
Best soil and position for Epilobium
- Sunlight
- Full sun
- Soil type
- Sandy, Loamy, Clay
- Soil moisture
- Well-drained, Moist but well-drained
- UK hardiness
- H7
Plant details
Epilobium angustifolium 'Isobel' size, habit and characteristics
- Height
- 2.0 m
Frequently asked questions
Where is the best place to plant Epilobium angustifolium 'Isobel'?
Epilobium angustifolium 'Isobel' prefers full sun.
What soil does Epilobium angustifolium 'Isobel' need?
Epilobium angustifolium 'Isobel' is adaptable and grows happily in most soil types, including sandy, loamy and clay. Aim for soil that stays well-drained to moist but well-drained.
How big does Epilobium angustifolium 'Isobel' grow?
Epilobium angustifolium 'Isobel' reaches a height of 2.0 m.
Is Epilobium angustifolium 'Isobel' hardy in the UK?
Epilobium angustifolium 'Isobel' has an RHS hardiness rating of H7, meaning it is fully hardy throughout the UK, tolerating temperatures below -20°C.
More in the Epilobium genus
- Epilobium angustifoliumFireweed
- Epilobium angustifolium 'Album'White Fireweed
- Epilobium dodonaeiDodonaeus' willowherb
- Epilobium fleischeriAlpine willowherb
- Epilobium latifoliumdwarf fireweed
- Epilobium luteumyellow-flowered Californian willowherb
