Hair Cap Mosses - Polytrichum commune, Polytrichum juniperinum
Polytrichum Moss, native to Canada’s boreal forests, are known as acrocarps. This means that unlike the velvety green carpet that springs to mind at the word “moss,” Hair Cap Mosses have an upright growth habit with leaves and stems. In appearance, they resemble short, soft stems of bright evergreen boughs sticking up vertically from the soil. There are two main varieties of Hair Cap Moss: Common Hair Cap and Juniper Hair Cap. Common Hair Cap Moss is taller and more commonly used in landscaping, either as a groundcover or an alternative to grass lawns. It reaches more than six inches in height, producing bright green leaves and stems. These form a lush carpet of greenery that spreads very slowly to fill the available space. Juniper Hair Caps, by comparison, are smaller, typically only growing to be five inches tall and often forming clusters rather than carpets. These have the blue-green color and shape of juniper boughs. Both varieties prefer neutral to acidic soil, and partial to deep shade. Though mosses will do well on a variety of soils, very sandy soils can pose a problem as they may erode away from beneath new plantings and prevent successful anchoring. Mosses do not have extensive root systems, so contact with the soil is crucial in establishing new plantings. Unlike stream-bank mosses, Hair Caps do not require constant water; in fact, over-watering can cause browning and even death. Instead, water lightly each day for the first two months after planting, until the moss is established. Then switch to watering lightly once a week for two months, and once a month after that until the moss has reached the desired size. For established mosses, no watering is necessary except during periods of drought that last three weeks or more.