Royal fern
Osmunda regalis · Osmundaceae
The largest hardy fern: broad fronds with well-spaced, oblong leaflets like those of a locust tree, tipped with rusty spore clusters. It grows at the water's edge.
- Size
- 5 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 royal fern
The planner designed this bed around 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 royal fern stands where it does.
The plants
- 1 Royal fern × 1, green leaves
- 2 Lingonberry × 10, pink
- 3 White barrenwort 'Niveum' × 3, white
- 4 Turtlehead 'Hot Lips' × 3, pink
- 5 Gray's sedge × 3, green
- 6 Celandine poppy × 8, yellow
- 7 Yellow trout lily × 8, yellow
- 8 Fumewort × 12, purple
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
Why here
- Anchors a back corner. At 5 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 Gray's sedge (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 7 groups (86%) are drifts, longer along the bed than they are deep. Cool colours (pink and purple) with yellow as the warm note, and white and green to calm things between them. The flowering is at its height from late April, with 4 kinds out together.
The planner's own design check: 11 Excellent, 5 Good, 1 Satisfactory. 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 royal fern goes in a border
At 5 ft it belongs at the back of a bed. In the planner's ten height classes it is tall (4 to 5 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 fern with the presence of a shrub, and a leaf that does not look like a fern at all. In wet soil it grows head high and turns gold and russet in autumn.
- A magnificent specimen beside water
- Bog gardens
- Autumn colour
What to plant with royal fern
Plants recorded as good partners for it, and what each pairing does:
- Japanese iris: adds the flowers, late June to mid July; low enough (3 ft) to stand in front of it; happy in the same wet soil.
- Rodgersia: adds the flowers, late June to mid July; bold leaves against its medium ones.
- Ligularia 'The Rocket': adds the flowers, early July to early August; bold leaves against its medium ones.
Questions about royal fern
Does royal fern need sun or shade?
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 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 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 5 ft (150 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many 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 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.
Is there a native plant like royal fern?
Royal fern comes from Europe, Asia and northern Africa. These North American natives come closest to doing its job:
- Purple-stemmed royal fern: the same job in a bed; 12 in shorter, bold leaves, not medium.
- Wallich's wood fern: the same job in a bed; 16 in shorter, 6 in narrower.
- Ostrich fern: the same job in a bed; 12 in shorter.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat 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 royal fern look like in winter?
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
- Purple-stemmed royal fern Osmunda regalis 'Purpurascens'
In these guides
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Fern
- Size
- 5 ft (150 cm) tall, 3½ ft (100 cm) wide
- Plant
- 3 ft (90 cm) apart
- Height class
- Tall (4 to 5 ft)
- Place in the bed
- Back
- Flowers
- None: grown for its foliage
- Leaves
- Medium texture, herbaceous; green
- 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.