Purple-stemmed royal fern
Osmunda regalis 'Purpurascens' · Osmundaceae
The fronds come up wine purple in spring and turn green, keeping their purple stems all summer; butter yellow in autumn.
- Size
- 4 ft tall, 3½ ft wide
- Zones
- 3 to 9
- Light
- Part sun to shade
- Flowers
- Grown for its leaves
- Pets
- No toxicity recorded
- Job in a bed
- Specimen
A bed built around purple-stemmed royal fern
The planner designed this bed around purple-stemmed royal fern when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 6, part shade. It chose the other plants from the 354 that suit those conditions and its wet soil, and says below why purple-stemmed royal fern stands where it does.
The plants
- 1 Purple-stemmed royal fern × 1, green leaves
- 2 Green-and-gold × 11, yellow
- 3 Lingonberry × 8, pink
- 4 Turtlehead 'Hot Lips' × 3, pink
- 5 Northern sea oats 'River Mist' × 3, green
- 6 Masterwort × 3, white
- 7 Fawn lily 'White Beauty' × 10, white
- 8 Yellow trout lily × 5, yellow
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
- The only bold leaves here. The rest are medium and fine. A change of leaf keeps plants distinct when nothing is in flower.
Why here
- Anchors a back corner. At 4 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to northern sea oats 'River Mist' (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A feature plant is seen as an object, and needs clear ground around it.
Why now
- Here for its leaves, spring to frost. They cover the 15 weeks between early March and late November when nothing on the plan is in flower.
Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. The front edge is finished with lingonberry and green-and-gold. Green-and-gold is the plant there is most of: 11 of the 44. Every line of the Design check comes out Good or better.
The planner's own design check: 14 Excellent, 3 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where purple-stemmed royal fern goes in a border
At 4 ft it belongs at the back of a bed. In the planner's ten height classes it is moderately tall (3 to 4 ft).
Its job: specimen. A feature plant with a shape of its own. It stands alone with room around it, and repeats only at a distance.
A royal fern with an extra season. In wet soil it stands full sun. A fine partner for the fresh green of other waterside plants in May.
- Pond and stream sides
- Purple spring fronds
- A large fern for wet soil
What to plant with purple-stemmed royal fern
Plants recorded as good partners for it, and what each pairing does:
- Japanese iris: adds the flowers, late June to mid July; medium leaves against its bold ones; happy in the same wet soil.
- Marsh marigold: adds the flowers, mid April to early May; medium leaves against its bold ones; low enough (16 in) to stand in front of it.
- Ligularia 'The Rocket': adds the flowers, early July to early August.
Questions about purple-stemmed royal fern
Does purple-stemmed royal fern need sun or shade?
Purple-stemmed royal fern grows in part sun (4 to 6 hours of sun, including some afternoon sun), part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).
It wants moist to wet soil, rich in organic matter, and plenty of water. It copes with soil that stays wet.
What zones does purple-stemmed royal fern grow in?
USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should purple-stemmed royal fern be planted?
3 ft (90 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3½ ft (100 cm), so a group knits into one patch.
It grows 4 ft (120 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many purple-stemmed royal fern plants do I need?
At 3 ft apart, set out in staggered rows:
- 1 to fill 10 square feet (about 1 m²)
- 4 for a single row 10 ft (3 m) long
- 4 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one, with clear ground around it: a feature plant is seen as an object, and a group of them is a thicket.
In the bed above, the planner used one in one group.
Is purple-stemmed royal fern poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat purple-stemmed royal fern?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
What does purple-stemmed royal fern look like in winter?
Purple-stemmed royal fern dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
More Osmunda
- Interrupted fern Osmunda claytoniana
- Royal fern Osmunda regalis
In these guides
- Plants for wet soil and rain gardens
- Deer-resistant plants for shade
- Pet-safe plants for shade
- Native plants for shade
- Garden plants native to Canada
- Plants with purple and burgundy leaves
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Fern
- Size
- 4 ft (120 cm) tall, 3½ ft (100 cm) wide
- Plant
- 3 ft (90 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- None: grown for its foliage
- Leaves
- Bold texture, herbaceous; green, purple
- Shape
- Vase-shaped, clumping
- Hardy in
- USDA zones 3 to 9
- Light
- Part sun, part shade, shade
- Soil
- Rich, moist to wet
- Water
- High
- Feeding
- None needed
- Family
- Osmundaceae
- Comes from
- Europe, Asia and northern Africa
- Stands up to
- Deer, wet soil
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.