Ferns Growing in a Brick Wall

Alkaline Tolerant

• If your bricks contain limestone, choose alkaline- or high-pH tolerant fern species. Southern maidenhair ferns (Adiantum capillus vereris) tolerate high levels of alkalinity and grow on limestone brick walls. These deciduous ferns grow from 10 to 24 inches tall and have feathery fronds. Their bright-green foliage is fan-shaped and bi- or tri-pinnate. Southern maidenhair ferns have short rhizomes and prefer moist, fertile soil and partial to full shade. The fragile or brittle bladder fern (Cystopteris fragilis) only grows from five to 10 inches tall. This deciduous fern has upright, lacy fronds and a smooth stem. Fragile ferns grow well in alkaline soil and have stout rhizomes. They spread easily and grow well on brick. Fragile ferns require moist soil and are partial to full shade.

Natives

• Several native North American ferns grow well on brick. The deer or hard fern (Belchnum spican) grows from 16 to 36 inches tall and has leathery, dark fronds that grow in rosettes. Deer ferns form vase-shaped clumps and have upright rhizomes. These evergreens prefer rich, fertile soil and are partial to full shade, through they do tolerate some sun. The American rockbrake or parsley fern (Cryptogramma acrostichoides) is native to much of western North America. It prefers moist soil and partial sun to partial shade. It has lacy foliage, dark-brown stems and short, scaly rhizomes. American rockbrake fern spores grow well on brick and in rocky sites.

Holly Ferns

• Some members of the Cyrtominum genus known as holly ferns grow on brick walls. The holly leaf fern (C. falcatum) grows up to two feet tall and prefers fertile, moist soil and shady sites. This evergreen fern has broad foliage and spreads into a dense ground cover. Holly leaf ferns grow well outdoors, where their spores often sprout on mossy brick surfaces. This fern thrives in warm climates and is subject to leaf scorch in full sun exposures. The Japanese holly fern (C. fortunei) grows up to two feet tall. This evergreen has tough, leathery, gray-green foliage that grows in an arching vase shape. Japanese holly ferns grow best in fertile, moist soil and tolerate sunny to shady sites. They thrive on porous brick and have thick, scaly rhizomes.

Other Species

• A few other species grow well on brick. The rabbit foot fern (Microsorum scolopendria or Polypodium scolopendria), also known as the wart fern, serpent fern or maile-scented fern, has green rhizomes or rootlets covered with brown, snake-like hairs. Rabbit foot ferns have tough, leathery foliage covered with large, protruding spore clusters. They prefer morning sun, afternoon shade and moist soil. The Huguenot or spider brake fern (Pteris multifida) has thin, bright-green, 23-inch-long fronds and dark brown stems. This fern is deciduous in cooler climates and semi-evergreen in warm regions. It has stout rhizomes covered with red-brown scales. The Huguenot fern grows well on brick and in rocky sites.