What: Blechnum penna-marina is a top-rate garden plant. The evergeen fern’s new fronds emerge in the spring copper red and gradually fade to rich green. It slowly creeps to fill cracks and crevices between paving stones or rockery walls. It can also be used as a small-scale groundcover. Plant alpine water fern under shrubs or trees with high branches, so that it gets some light for the best spring color.
Where: Alpine water fern grows best in moist to well-drained soil and will tolerate sandy soils or clay.
Size: This spreading fern can grow to be 6 inches tall with a span of 5 feet when mature.
Care: Provide light to dappled shade and occasional watering during dry weather. It can be grown full sun with regular watering in summer and protection from hot locations. Cut it to the ground in late winter to gain the full effect of the colorful spring growth.
— Richie Steffen, Great Plant Picks