Mosses in the garden; good or bad?

 

Moss growing on my brick patio.

Moss growing on my brick patio.

   There are many moss-like plants.   Sea Moss is actually algae; Reindeer Mosses are lichens; Clubmosses (Lycopodiums and Selaginellas) are vascular plants more closely allied with Horsetails; Spanish Moss is a bromeliad (related to Pineapples); Irish and Scotch Moss are in the carnation family.

     True mosses, in the class Musci; include “true” mosses, peat mosses, and granite mosses.    They are primitive “non-vascular plants,” meaning that they have no tissues for conducting water or nutrients such as the xylem or phloem in “higher” plants.

    Plants that have no vascular tissue cannot grow large.  They need to absorb moisture and nutrients from their surroundings.  Because of this, like lichens, mosses are very susceptible to air pollution.  They need to live in moist places during part of their life cycle.  Mosses may be found on the ground, on rocks and cliff faces, near waterfalls, on rotting logs, and in bogs.  Mosses or other plants that grow on trees are called epiphytes.  There are about 700 species of “true mosses” and about 40 species of Sphagnum peat moss in our region.

    Do you consider moss a pest?  It may be–when it is growing on your roof–Just make sure that you use an environmentally-friendly, “least toxic,” product when controlling moss on structures. 

    Many people in their quest for a perfect lawn will use chemicals to kill moss.  Proper management is a better strategy–Rake the lawn to remove thatch and moss, aerate it to make sure it drains freely and overseed to fill in bare spots.  Irrigate adequately during dry periods to keep the grass healthy but do not let water puddle, follow a recommended fertilizer program, apply lime to keep the pH between 6.0-6.5, and mow grass at the proper height for the species.   In shady areas, turfgrass grows poorly; other groundcovers may be more suitable—mosses, at least, are green! 

    A Moss Garden can be an attractive feature in a woodland garden.  I saw a You-tube video that made it sound easy—all you had to do was acidify the soil!  Mosses grow best at a pH of ~5.5.  To try to encourage more moss, I tried a little experiment in my yard.  After testing the pH of my soil, I endeavored to lower the pH a little more.  The only products readily available for acidifying soil are aluminum sulfate (usually sold for making hydrangeas bluer), and elemental sulfur (often sold for treating fungal diseases).  It was difficult to quantify the results.  The amount of mosses varies dramatically through the seasons and unfortunately, the grass still survived.  The plots treated with the aluminum sulfate, however, appeared to have a little more moss.

    For the best success, you really should start with bare ground in a shady location, removing all the grass, weeds, leaves and debris.   Next, scratch up the soil to loosen it slightly and moisten the soil.  There are two methods for establishing moss in a new area.  You can transplant entire clumps of moss to the new spot or make a “moss milkshake” to spread over a larger area by mixing clumps of moss with buttermilk or beer in a blender (using a few types of moss insures a better success rate).  Just make sure to mist or water regularly and remove any leaves or debris that fall on the moss.  These methods also work well for establishing moss on rocks, in between pavers, in bonsai, fairy gardens, or other special container gardens.

    A Moss Garden is a great project for an environmentalist on St. Patrick’s Day!  After all, is anything greener than moss?

(This article was first published in the Peninsula Gateway on March 16, 2011)

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