The Selection, Collection, and Propagation of Mosses for ...

Mosses are bryophytes, and as such have poorly developed water and food conducting systems. These factors do not limit moss’s success because over thousands of years mosses have evolved to grow only in moist places and/or use poikilohydry, drying up and becoming dormant when water is scarce (Vitt, Marsh and Bovey 60). As such, the distribution of mosses is dependant on two climatic factors— temperature and precipitation (Vitt, Marsh and Bovey 7).

Only the mosses with a history of successful propagation and native to Washington and Oregon— where the Northwest Eco Building Guild has chapters— have been included in their study of ecology and EcoRoof value. Generally speaking, however, most mosses native to Washington and Oregon are also native to a large portion of British Columbia and Idaho, due to the similarity in climate within this geographical area. Schenk’s book, Moss Gardening, was used to identify what genera and species had EcoRoof potential, mainly for their relative ease of human propagation. Vitt, Marsh and Bovey’s book, Mosses, Lichens & Ferns of Northwest North America, has been used to identify where potential EcoRoof mosses could be collected, and consequently, what microclimate best suit individual species.

The inspiration for using mosses on EcoRoofs stemmed from the fact that mosses readily self-propagate themselves on roofs, often to the unfortunate disdain of those beneath them. Spores successfully grow on rooftops because they are large areas without any competition; further, in the Pacific Northwest, they often stay moist due to the wood shingle construction that absorbs water, and overhead shading by tree branches (Schenk 69).

Species selection:

The chart titled “Mosses suited for EcoRoofs” (page 6) describes many species of mosses that, with proper cultivation, should perform quite well. Additionally, consider:

The air pollution of cities can prove fatal to many moss species; Bryum argenteum and Ceratoddon purpureus, however, are highly resistant to air pollution and grow well in industrial areas (Schenk 168).
The following genera and species are particularly known for their landscaping value in that they are easily transplantable and dependable ground covers: Calliergonella, Dicranum, Drepandoclatus uncinatus, Eurhynchium, Pogonatum, Polytrichum, Racomitrium canescens, and Rhytidiadelphus loreus (Schenk 248).

Most moss must be collected, as few are available through nurseries or growers (Schenk 159).

Notes on identifying and collecting mosses:

One can more easily identify a moss’s species using a 12-power loupe (Schenk 252).
Use one’s hands to lift the sample from the substratum. The sample should them be placed in an individual small paper bag or paper envelope previously labeled with the date and place of collection. Further notes may include: moisture, substrate, exposure, associated vegetation, and elevation (Vitt, Marsh and Bovey 24).

Soils for successful moss propagation:

For containers to grow moss from pulverized moss for the sole purpose of transplanting: Use builder’s sand and weed-free compost in equal parts (Schenk 98).
For containers where moss sods will be transplanted (i.e. EcoRoofs): Use 1/3 acidic loam, 1/3 builder’s sand, and 1/3 humus with an additional sprinkling of medium-sized water absorbent polymer crystals (Schenk 133). Besides mixing the crystals into the soil, layer a 1/2” of hydrated crystals at the bottom of the container; this will increase the longevity of the moss by harboring it from drought (Schenk 135).
To stimulate moss growth, treat soil with one of the following: fertilizer, egg whites mixed with water, plain milk, unsalted buttermilk, or beer (Schenk 60). When using fertilizers, make sure that there are no traces of calcium as it kills moss (Schenk 133).
Most moss prefer soil with a pH level around 5.5. Soil can be acidified to this pH by covering the ground with any of the following, followed by a sprinkling of water to adhere particles to the soil: powered sulfur, powered skim milk, powered aluminum sulfate, or rhododendron fertilizer (Schenk 81).
To prepare soil for moss inhabitation, keep the ground weeded and smoothly raked, as well as free of leaf liter and other debris (Schenk 85).

Methods of propagation:

Simply transplant moss from one like area to another (Schenk 89). Plant hand-sized moss sods at spaced intervals of 1’ (30cm.), fix in place with bobby pins or flat, wooden toothpicks bent into a “v”, and wait for the moss’s growth to fill in the barren areas (Schenk 91, 115, 158). Moss should be watered daily until it has acclimated to the site. (Schenk 136)
Take dried, collected samples of moss and pulverize them by rubbing them across a mesh screen, with openings of 1/4” – 3/8” (Schenk 156).
Make a “moss-mud slurry” by adding 1 lb. of leaf mold, acidic garden loam or barnyard manure to a large jar and then add water until the jar is 2/3 of the way full. Cap the jar securely and shake vigorously until the contents are well mixed; allow contents to settle. Pour off the water, along with whatever’s floating in it. Scoop one cup of the slurry into a blender and blend with a pancake-sized sod of moist moss. Pour the moss-mud slurry directly onto soil or onto a brick resting in a plate of water; moss grown on the brick can be transplanted to soil later (Schenk 158).

Maintaining mosses:

Birds and rodents often disturb mosses by taking pieces of their turf for nest building. This can be prevented by covering areas of moss growth with black nylon netting with a one-inch mesh (Schenk 170). However, since the aim of EcoRoofs is environmental in nature, it may behoove us not to dictate whom or what benefits from the moss’s presence.

Shrubs and perennials that grow well with moss:

Shrub genera and species: Euonymus occidentalis, Kalmia microphylla ssp. occidentalis, Mahonia, Rhododendron, Vaccinium, and Viburnum (Schenk 104).
Perennial genera and species: Asarum caudatum, Camassia, Carex, Cimicifuga elata, Cornus canadensis, Dicentra, Disporum, Dodecatheon, Erythronium, Fragaria vesca, Galium, Linnaea borealis, Luzula, Oxalis, Smilacina, Streptopus, Thalictrum, Tiarella, Tolmiea menziesii, Trillium, and Viola (Schenk 104).

Containers:

If any part of the EcoRoof will be made from concrete, mixing peat with the concrete will encourage self-propagating mosses (Schenk 131).

For further information:

Research: Sir John R. H. Thouron’s Doe Run is home to a moss house, a structure built to grow moss (Schenk 43).
Contact: David G. Long, Edinburgh’s Royal Botanic Garden’s bryologist who maintains the Fern House that is coached to grow moss (Schenk 45).
Read:

The Forests of Lilliput: The Realm of the Mosses and Lichens. By John Bland. 1971. Prentice Hall, Englewood Cliffs, New Jersey (Schenk 255).
How to Know the Mosses and Liverworts. By Henry S. Conrad. 1956. Revised by Paul L. Redfearn, Jr. 1979. Wm. C. Brown Company, Publisher, Dubuque, Iowa (Schenk 256).

Mosses suited for EcoRoofs:

Genus:	Species:	Geographically native to:	Native habitat:	Notes on propagation:	Additional comments:	Source:
Atrichum	selwynii	W. WA and W. OR's coniferous forests	Acidic soils in mesic areas		Found with Dicranella	Vitt, Marsh and Bovey 60
Aulacomnium	palustre	All WA and all OR's artic-alpine tundras, subartic-subalpine forests-tundras, coniferous forests, and peatlands		Likes water’s edges; keep moist		Vitt, Marsh and Bovey 78; Schenk 179
Barbula	convoluta	All WA and all OR's dry coniferous forests, deciduous forests, and grasslands-savannas		Grows best on sunny ground		Vitt, Marsh and Bovey 122; Schenk 179
Brachythecium	rivulare	W. and far E. WA and W. OR’s subartic-subalpine forests-tundras, and coniferous forests		Grows best on shady ground	Found with Philonotis fontana	Vitt, Marsh and Bovey 97; Schenk 180
Brachythecium	salebrosum	All WA, except SE corner, and NW OR’s subartic-subalpine forests-tundras, dry coniferous forests, and deciduous forests		Grows best on shady ground		Vitt, Marsh and Bovey 98; Schenk 180
Brachythecium	asperrimum	W. WA and NW OR’s subartic-subalpine forests-tundras, and coniferous forests	Wet grounds in lowland coastal forests	Grows best on shady ground		Vitt, Marsh and Bovey 99; Schenk 180
Bryum	caespiticium	All WA, except SE corner, and W. OR’s alpine-artic tundras, subartic-subalpine forests-tundras, dry coniferous forests, deciduous forests, and grasslands-savannas	Dry, calcareous soils, especially in weedy situations	Grows best in sandy soil in sun		Vitt, Marsh and Bovey 67; Schenk 181
Bryum	pseudotriquetrm	All WA and all OR, except SE corner, in alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, deciduous forests, and peatlands		Grows best in sandy soil in sun		Vitt, Marsh and Bovey 67; Schenk 181
Bryum	argenteum	All WA and all OR’s alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, deciduous forests, and grasslands-savannas	Sandy soils	Grows best in sandy soil in sun	Silver color is unique to B. argenteum	Vitt, Marsh and Bovey 68; Schenk 181
Bryum	miniatum	W. WA and W. OR’s coniferous forests		Grows best in sandy soil in sun	Forms golden to wine colored cushions	Vitt, Marsh and Bovey 68; Schenk 181
Calliergon	stramineum	W. WA’s alpine-artic tundras, subartic-subalpine forests-tundras, and peatlands	Swamps, fens, and peaty grounds	Grows best on damp ground; quick growing		Vitt, Marsh and Bovey 88; Schenk 185
Calliergon	sarmentosum	NW WA’s alpine-artic tundras, subartic-subalpine forests-tundras, and peatlands	Seepy, acidic cliff shelves and wetlands in alpine-artic tundras and subartic-subalpine forests-tundras	Grows best on damp ground; quick growing		Vitt, Marsh and Bovey 89; Schenk 185
Calliergonella	cuspidata	NW WA and NW OR’s peatlands		Grows best on damp ground; quick growing	Common in urban areas as a weed	Vitt, Marsh and Bovey 87; Schenk 185
Ceratodon	purpureus	All WA and OR’s alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, deciduous forests, and grasslands-savannas	Montane and boreal forests	Grows well on all soil types	Common on rooftops	Vitt, Marsh and Bovey 130; Schenk 186
Climacium	dendroides	W. WA and NW OR’s alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, deciduous forests, and peatlands	Mesic organic soils	Grows best on wet soils in shade to nearly full sun		Vitt, Marsh and Bovey 113; Schenk 191
Dicranella	varia	W. WA and W. OR’s subartic-subalpine forests-tundras, coniferous forests, and deciduous forests	Exposed, moist, inorganic soil			Vitt, Marsh and Bovey 126
Dicranum	scoparium	All WA and all OR, except SE corner, in alpine-artic tundras, subartic-subalpine forests-tundras, and coniferous forests	Sheltered, moist, spruce-fir forests	Propagates well using the transplant method; grows best in deep, peaty humus in full sun to 3/4 a day in full shade		Vitt, Marsh and Bovey 124; Schenk 191
Dicranum	polysetum	E. WA’s subartic-subalpine forests-tundras and dry coniferous forests	Upland boreal and montane forests	Propagates well using the transplant method; grows best in deep, peaty humus in full sun to 3/4 a day in full shade		Vitt, Marsh and Bovey 124; Schenk 191
Dicranum	undalatum	W. WA’s peatlands	Organic soils in muskeg habitats	Propagates well using the transplant method; grows best in deep, peaty humus in full sun to 3/4 a day in full shade		Vitt, Marsh and Bovey 125; Schenk 191
Drepanocladus	uncinatus	All WA and all OR, except SE corner, in alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, and peatlands		Easy to propagate; likes upland wood conditions with lots of sun;		Vitt, Marsh and Bovey 90; Schenk 196
Eurhynchium	pulchellum	All WA and all OR’s alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, deciduous forests, and grasslands-savannas	Boreal and montane forests, especially aspen forests	Grows taller and fluffier when in shade		Vitt, Marsh and Bovey 94; Schenk 197
Hypnum	lindbergii	NW WA’s alpine-artic tundras, subartic-subalpine forests-tundras, dry coniferous forests, deciduous forests, and peatlands	Wet fen habitats, especially at bases of sedge clumps	Easy to transplant; likes upland ground		Vitt, Marsh and Bovey 102; Schenk 201
Leucolepsis	menziesii	W. WA and W. OR’s wet coniferous forests	Humid coastal forests, on logs, boulders, and soil	Grows best in deep, fertile sand in part shade, or boggy ground in full sun		Vitt, Marsh and Bovey 72; Schenk 208
Philonotis	fontana	All WA and all OR’s alpine-artic tundras, subartic-subalpine forests-tundras, coniferous forests, and peatlands	Calcareous seepages or springs	Grows best in moist soils with good drainage		Vitt, Marsh and Bovey 81; Schenk 223
Plagiothecium	denticulatum	W. WA and W. OR’s alpine-artic tundras, subartic-subalpine forests-tundras, and coniferous forests	Swampy soil, moist humus, and grassy fens	Overpowers other mosses, but doesn’t hinder ferns’ or flowering plants’ growth; grows best in shady, humus soil; successful, but slow propagation	Makes woodland carpets	Vitt, Marsh and Bovey 101; Schenk 224
Plagiothecium	undulatum	W., SE WA and W. OR’s wet coniferous forests	Shaded, low-elevation rainforests on logs, boulders, and soil	Overpowers other mosses, but does’nt hinder ferns’ or flowering plants’ growth; grows best in shady, humus soil; successful, but slow propagation		Vitt, Marsh and Bovey 101; Schenk 224
Pohlia	cruda	All WA and all OR’s alpine-artic tundras, subartic-subalpine forests-tundras, and coniferous forests	Inorganic soils and peat banks	Easily cultivated if not allowed to become too hot and/or dry	Low, matting moss	Vitt, Marsh and Bovey 69; Schenk 226
Pohlia	filum	Far W. WA and all far W. OR’s alpine-artic tundras and subartic-subalpine forests-tundras	Exposed mineral soil	Easily cultivated if not allowed to become too hot and/or dry	Low, matting moss	Vitt, Marsh and Bovey 71; Schenk 226
Pohlia	longibracteata	Far W. WA’s wet coniferous forests	Sandy cliffs and banks of coastal forests	Easily cultivated if not allowed to become too hot and/or dry	Low, matting moss	Vitt, Marsh and Bovey 70; Schenk 226