Using Pebbles as Mulch

    Recent summers in our area of Ontario, Canada, have become increasingly drier. As our garden is located on a gravel ridge this lack of moisture has been a real challenge in some part of our garden. In the spring of 2002 Bill decided to eliminate some of the lawn in a part of the garden where the lawn disappears into brown crispness by late July. Within the last year or so an aggressive miniature geranium type looking weed, which we have not yet been able to identify, has taken over from much of the grass. We do not have an endless supply of water or the enthusiasm to maintain a lawn in this dry area so we chose to extend one of the pebble beds at the south end of the lawn.

Bill uses his pick axe to make planting holes.

To begin the expansion of the pebble bed Bill used his pick axe to define the new edge of the bed. Next he decided where the planting holes were to be. Using his pick axe he dislodged the pebbles, stones and soil in each hole.      The "garden" in the background is made in a similar way with each of the plants being planted in a hole of its own. Gradually, as the plants grow bigger and spread over the pebble mulch, there is an appearance of a planted garden. It takes some time for this effect to be created but is well worth the wait!     Why do we use pebble mulches? As Bill says, "Because we have lots of pebbles!" Weeding is reduced. It is quite easy to pull the few weeds that attempt to grow among the pebbles. Weeding the holes in which individual plants grow is easy too. There is limited space for the weeds to grow in. As the plants mature and fill up the planting spaces there is less room for weeds to find a footing.

Two pieces of essential equipment.

After loosening the rocks, pebbles and soil, Bill uses a shovel to remove all the material to the home-made screen which rests across the wheelbarrow. Larger rocks are picked out and put to one side. All the soil is sifted through the screen, which is sometimes known as a raddle.The pebbles are moved up and down the screen to loosen the earth. A sturdy pair of gloves are the other essential items for this task. We remove any grass roots and put them in the compost.

    To stop the grass from coming up through the pebble mulch we have found that a heavy layer of newspaper and then a layer of plastic on top works very well. Murphy's Law dictates that the wind will always blow on a day when we are spreading newspapers so we have a large plastic container in which we dampen the newpapers before we attempt to spread them. The newspapers cover all of the area that will not be planted. The newspapers hang down into the planting holes to protect the plasic from the stones bordering the planting hole and to discourage the grass. Plastic, usually from our recycling collection, covers all of the area. We pierce the plastic over the planting holes and the "flaps" hang down into the holes, as you can see in the photo. The newspapers and the plastic help to retain moisture, another important reason for mulching. On top of this plastic the pebbles that were recently in the planting holes are spread in a thick layer. Larger flat rocks are used as edging for the bed.

Bill puts down the newspaper mulch first.

    We worked on extending this pebble bed over a couple of days. On a drizzly spring morning we filled the planting holes with a mixture of earth that was sifted through the screen, compost, peat moss and other soil.

Bill mulches daylilies and irises.

We mulched each of the new daylily plantings with a layer of sawdust to help reduce the chances of weeds taking root. The irises were also mulched this way though we took care to keep the mulch away from the iris rhizomes.     We have experimented with various mulches and have discovered that pebbles mulches work well in nearly all parts of our garden. The newly exposed rocks get cleaned off by the wind and rain. Eventually new sections of the mulching are joined invisibly into the previous bed.     The only time we are less than satisfied with the areas of pebble mulch is in the spring. That's when we clean up the fallen leaves from the Fall. We've noticed that none of the gardening books that enthusiastically endorse pebble mulches have anything to say about this problem!

Peonies and Centranthus rubra fill a pebble bed.

In the spring this pebble bed features peonies, centranthus rubra and Japanese irises. Because the bed is quite wide Bill put a pathway of stepping stones so visitors can walk through the garden. In summer the centrathus blooms non-stop.

A quiet sitting place at the edge of the pebble bed.

At the end of the stepping stone path there is a quiet shady place to sit. The hostas have been planted in planting holes that were filled with lots of rich soil. The ground cover was planted through slits cut in the plastic and the newspapers.

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