Comptonia peregrina aka Sweetfern

Comptonia peregrina, or sweet fern, belongs to the Myricaceae family. It grows wild in eastern Canada and the north-central and eastern United States. Despite its name, this plant is a woody shrub. Its leaves look like fern fronds, but fall each year. Wild plants grow along roads and on gravel banks. The shrub can fix nitrogen and grow in poor soil.

Garden plants reach about 2–5 feet [0.6–1.5 metres] tall. Their spread reaches about 4–8 feet [1.2–2.4 metres]. RHS lists a taller limit of 8.2 feet [2.5 metres]. The shrub forms a low mound with many slim, upright stems. Rhizomes and suckers help it form broad colonies over time. Young twigs have fine hairs and a grey-brown colour. Smooth bark has a red-brown sheen and many small lenticels. Older stems may show copper or purple tones and resin dots.

The narrow leaves have deep lobes and a glossy surface. Each leaf is simple, despite its fern-like outline. Leaves start pale green, then turn olive or dark green. Crushing them releases a strong scent. Some leaves show red, orange, or yellow tones. Autumn leaves often turn brown and offer little colour. Small flowers open in April and May. Each plant bears both male and female flowers. Brown male catkins appear before or with the new leaves. Female flowers have a yellow-green colour. Clusters of green-brown nutlets follow, with a burr-like look. The fruit appears in fall.

Grow sweet fern in sun or some shade. It favours sandy loam with good drainage and an acid pH. RHS also accepts neutral soil and clay. Moist soil suits it, but established plants tolerate drought. It also tolerates wet sites and wind. Sources place it in USDA zones 2–6 and UK rating H5. UConn reports poor growth in climates warmer than zone 6. Moving plants can be hard, and new plants may struggle to settle. Root cuttings, layering, and suckers offer ways to raise more plants.

Sweet fern suits native gardens and spaces where colonies can spread. Its roots help hold soil on slopes and road banks. It also suits rain gardens and sheltered coastal sites. The foliage provides scent rather than a bold flower display. It attracts butterflies and songbirds, and deer tend to avoid it. Sources report few major pest or disease problems. Once settled, it needs little upkeep, though its spread needs space.