About
Blechnum penna-marina, the alpine water fern, is a mat-forming, evergreen fern producing spreading rosettes of simply pinnate, deep-green, sterile fronds to 15 cm long and narrower, erect fertile fronds, the young fronds often reddish. An excellent and ornamental ground-cover fern for a moist, shaded position.
About the genus
Blechnum are mostly evergreen ferns with erect or creeping rhizomes and simply pinnate, leathery fronds, the fertile ones usually erect and the sterile often spreading. They are grown for their elegant, year-round foliage in moist, shaded garden positions.
Growing conditions
SunlightFull shade, Partial shade
Soil typeLoam, Sand
Soil pHAcid, Neutral
Soil moistureMoist but well-drained, Poorly-drained
AspectEast-facing, South-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH4
Plant details
Plant typeFerns
HabitMatforming
FoliageEvergreen
Height0.1-0.5 metres
Spread0.5-1 metres
Time to full height5-10 years
Suggested usesCity and courtyard gardens, Cottage and informal garden, Patio and container plants
Native toSouth America, Australia, New Zealand
Care notes
CultivationEasy to grow in most cool, moist, shaded sites. See how to grow ferns for further advice
PruningDead or damaged fronds may be removed as necessary
PropagationPropagate by sowing spores (may not come true) in mid to late summer or by division in spring
Pest resistanceGenerally pest-free outdoors
Disease resistanceGenerally disease-free outdoors