mosses

As the verdure of summer and the vibrant reds, oranges, and yellows of
fall fade into memory in January, my eye seeks out the merest color in a
drab, gray and white landscape. It is at this time of year that I am
especially drawn to mosses. Mosses on the whole continue to grow as
long as the temperatures remain above freezing and they have access to
water, suspending their growth during cold snaps or dry spells and
starting up again when temperatures moderate and the rains return.
Thus, many remain vibrant, rich shades of spring green even in the dead
of winter in contrast to the muted evergreen of the laurels, hollies, pines
and other larger plants that hold their leaves though the year. There are
a few places on earth where mosses really dominate the landscape, such
as the great peat bogs of the boreal lands, the temperate rainforests of
Northwestern North America, Chile, and New Zealand, the cloud forests
of tropical highlands, and the ground under firs and spruce in places like
Maine and Northern Ontario. Elsewhere, they play a more minor roll in
the canvas of life, seeking out niches that are too shady, wet, or exposed
for other plants to grow. Mosses lack the complicated vasculature of
most other plants; the xylem and phloem that shunts water,

nutrients, and the
products of
photosynthesis from root
to leaf and back again.
For a moss, water
transport is a slow and
local process. Without
plumbing, the H2O flows
from one cell to the next
by osmosis or by simple
capillary attraction just
as water is wicked up by
a kitchen sponge.
Sphagnum mosses are a
perfect example of this.
The dead parts of the
ever lengthening stems
wick water to the live tips
from below, allowing the
mat to rise up above the
water of ponds and bogs
in floating pillows.

Consequently, mosses can never venture very far from soil, rock, or tree and the reserve of water these substrates provide unless they grow in extremely wet
places like the cloud and temperate rain forests. In the cooler boreal regions of the globe such as much of Canada and Alaska, large mosses luxuriate under
conifers that shade the ground and prevent it from drying out. The same is true in cool maritime climates like those of the British Isles and much of Japan. In
these places, it is possible to cultivate luxuriant carpets of moss in the manner of turf with just a moderate amount of attention and care. Species like
Hylocomium splendens (top left), Rhytidiadelphus triquetrus (top right), Ptilium crista-castrensis (bottom left), and Pleurozium schreberi (bottom right) carpet
the ground in a 3 inch, spongy carpet.

In my area, the climate is cool enough and wet enough that many mosses thrive, though not with the dominance seen in the regions described above. With the
exception of sphagnums, most of our local species are opportunists that colonize places too barren and exposed for larger plants. Just about every shaded tree
trunk, outcrop, fallen log or stump is covered in mosses that survive the vicissitudes of these harsh microclimates because their simple physiology allows them to
go completely dry or frozen for months in end with no harm. Two of the most common are Hypnum imponens and Thuidium delicatulum - both carpeting
species that are easily transplanted to rotten stumps, logs, and low rocks. These protuberances in the wooded landscape offer mosses an important advantage -
they elevate the tiny plants above deadly blanket of leaves that rains form the tree canopy every autumn. There is one thing that mosses cannot abide, and that is
a smothering blanket of dead leaves or other debris. Big species like Hylocomium splendens (stair step moss) can push up through a scattering of fir needles, but
no moss can handle the barrage of maple and oak leaves in deciduous forests.

Some of my best moss patches are on large outcrops of Schist and quartz. One bit of
ledge, which I have nicknamed Whale Rock, is about 30 feet long and 10-15 feet wide
and it rises like the back of a leviathan from the surrounding woods. When we moved
here, it was covered with a dense stand of stunted white pine seedlings that could not
make much headway in the thin, scurfy duff that clung to its surface but which
nevertheless did their best to shade out any moss that might try to gain a foothold. On
the bare edges of the ledge, broom moss (Dicranum scoparium, left and below), along
with a few other speciesdid manage to grow. We have an abundance of pines on our
property, so I had no compunction about removing the stand of seedlings from the
outcrop and I inevitably dislodged some of the duff that had accumulated around their
roots. With the area newly cleared, I raked the broom moss with a metal leaf rake,
sweeping little bits that break off toward the bare areas in the center. After two years,
these took hold wonderfully well and now I must only weed out interlopers once a year
and clear off fallen leaves and sticks twice in autumn.

left) Whale rock in March 2004 after
removal of pines. The broom moss os
confined to the bare rock surfaces where it
can compete against larger plants.

(right) Whale rock in October 2006
photographed from the other end after the
broom moss has colonized the middle
sections of the ledge. I have just used a
backpack leaf blower to remove leaves and
sticks. A few forbs, notably wintergreen
(Gaultheria procumbens), partridgeberry
(Mitchella repens), and wild oats (Uvularia
sesslifolia) now prosper in the moss.
Seedlings of pink lady-slipper
(Cypripedium acaule) have popped up in
one area as well. In a declivity of the ledge
just out of the frame to the right, I planted
a few small clumps of Oconee Bells
(Shortia galacifolia). There is a bit more
duff there and water trickles in from the
ledge, creating conditions where the
Shortia has prospered. I am sprinkling the
tiny seeds into the moss in hopes a few will
take. Many woodland wildflowers, trees,
and shrubs prefer to germinate in beds of
moss, which can be a blessing or a curse.