Osmundastrum cinnamomeum

Osmundastrum cinnamomeum: Cinnamon Spikes Rising From a Green Vase

Cinnamon Fern sends up rusty brown fertile fronds that look like cinnamon sticks, then surrounds them with a bright green vase of fronds. THE SPICE RACK OF THE SHADE GARDEN.

Plant Characteristics:

• Botanical Name: Osmundastrum cinnamomeum (syn. Osmunda cinnamomea)
• Common Name: Cinnamon Fern
• Height: 90–150 cm (3–5 ft)
• Spread: 60–90 cm (2–3 ft)
• Flowers: None; it is a fern. Separate fertile fronds turn cinnamon brown in spring and fade by midsummer
• Foliage: Bright green, once-cut fronds in an upright, vase-shaped clump, turning yellow to tan in fall; small woolly tufts mark the base of each leaflet
• Features: Rabbit resistant, tolerates wet soil

Where to Plant: Use it where you want height and drama in a damp, shady garden: along a pond or stream, in a rain garden, in a low wet corner or at the back of a woodland bed. A single clump makes a fine focal point, and it's one of the few large perennials happy in soggy, acidic soil.

Companion Plants: Give cinnamon fern a moist to wet, shady bed with Jack-in-the-pulpit and a blue-gold hosta. Arisaema triphyllum adds hooded Jack-in-the-pulpit flowers at 30 to 60 cm from April to June. Hosta 'Sunny Halcyon' brings gold leaves at 30 cm. Onoclea sensibilis adds sensitive fern fronds at 30 to 90 cm. Liriope 'Big Blue' edges the front with grass-like leaves and violet spikes at 30 to 45 cm.

Plant Care: Plant it in part to full shade in rich, moist to wet, acidic soil with plenty of organic matter. It can handle more sun if the soil never dries out. In dry soil the fronds brown early and the plant may go dormant. Keep it well watered, especially the first year. A leaf mulch helps hold moisture. Cut back old fronds in late fall or early spring. It grows slowly from a compact crown, takes a few years to reach full size, and rarely needs dividing.

History: Cinnamon fern grows wild in swamps, wet woods and bogs across eastern North America, including Ontario and Quebec, with related populations in tropical America and eastern Asia. Long classed as Osmunda cinnamomea, it was later moved to its own genus, Osmundastrum, after botanists found it was less closely related to its look-alike cousins than once thought.

Final Thoughts: A native that loves wet soil and doesn't interest deer or rabbits. Plant a few by the downspout. ALL SPICE, NO OVEN.