Weed Cloth and Red Death Kill Soil

Two things kill the soil on most of our public and commercial landscapes and many residences in Grants Pass: weed cloth and fine bark mulch, also called Red Death, often used in combination.  Under the influence of water and gravity, dead soil compacts nearly as hard as rock.  Roots won’t grow in it; they grow on top of it, just under the cloth, under the bark or gravel covering the cloth, or in the Red Death.  Storm water, instead of percolating into such soil, runs off into streets, down storm drains, and pollutes our river.

Weed cloth (and its cheap relative, black plastic) kills soil by stopping the movement of worms and other soil life.  Worms under the cloth, unable to get to food on the surface, eventually run out of food under the cloth and starve.   Ants, the other great soil aerators, are not able to live under weed cloth either; nor are any other insects.  With no life to lighten the soil beneath the cloth, it compacts and loses oxygen, which roots need to breathe.  Any further root growth is on top of or just under the cloth, on top of the dead soil.

One might think it’s a good idea to put landscape cloth on paths under gravel or mulch, to make the soil compact and keep it that way.  But roots will grow on top of or just under the cloth; this gardener recently dug and cut out a cottonwood root that had grown 8 inches high across a path of cloth covered with gravel over a mere 7 years.

Another problem with weed cloth and plastic is that mulch will not stick to it, and it soon shows along the edges and anywhere the soil is humped, by the growth of roots for instance, and where it shows, it’s ugly.

Fine bark, or Red Death, kills soil by leaching bark’s toxic natural preservatives into the soil.  Trees make chemicals in their bark to protect themselves from insects, fungi, and bacteria.  Grind it up, break the plant cells, and those preservatives are released to leach into soil, where they quickly kill insects, fungi, and bacteria.  Dead as a doornail, the soil compacts under the influence of water, and roots begin to grow on top of the soil, in the bark.

Neither weed cloth nor Red Death kills plants directly, but some plants cannot stand compacted soil, sicken, and die.  That’s why businesses have pansies and petunias planted in blocks of potting soil, surrounded by Red Death.  Most common landscape shrubs in our town can take compacted soil, or they don’t last long and aren’t used by landscapers.  But they grow slowly and are not healthy in dead soil.

Weeds grow regardless; gravel or fine bark are dandy seedbeds for them, even on top of weed cloth.  They don’t have to be big to be ugly weeds; ugly little weeds spread just as readily and look just as ugly.  Seeds are tracked in and fly in.  Roots under the cloth find their way out along the edges.  So it doesn’t even work to stop weeds.

Larger screened bark, shredded wood-bark mixes like Walk-on fir, and chipped wood or trimmings do not kill soil, as the preservatives are kept in the bark.  It is the bark dust and small particles that leach enough preservatives to kill soil.  Since larger barks keep their preservatives, they last a lot longer.  The larger the bark, the longer it lasts, but walking is easiest on Walk-on and ¾” nugget, and Walk-on fir sticks well to slopes.

Completing a Blueberry Bed at the Parks Office

January 29th, 2014

I started working out front of the Josephine County Parks office back in mid-summer, when I was appointed to the Parks Advisory Board.  I went down to the Parks office to ask for permission to put up signs at the dog park for my weeding classes and filled out a volunteer application to make the classes official, and found out that I get a Jo Co Parks pass for being on the Board, and thus volunteering more than 8 hours per year. 

The first thing I saw was the railroad-tie bed in front of the office, with an ivy column at the far end, and roses, irises, blackberries and grass in the rest.  Having seen it, I had to do something with it, and requested permission to weed and mulch it.  I also asked if I could crown their roses when they were done blooming.  I scheduled a day to weed it and came back a week or so later to mulch the bed with heavy walk-on fir bark and crowned just one rose plant, as the other one was just coming into bloom.

All this time, I had been looking at the space on the other side of the rail of the entry walkway, an unusable space full of moss and false dandelion because no one walked there, an area about 12’ X 20’ between the front fence, walkway railing, and the fuel tanks next to the big gate.  I talked to our Parks Director about building a blueberry bed there in the fall, demonstrating using leaves as base mulch and pine needles as top mulch, as well as how to grow blueberries in Southern Oregon.  She thought it was a great idea. 

I started spraying the weeds with glyphosate in preparation for fall mulching, and repeated it once or twice through the summer.  Glyphosate (aka Roundup) is a heavy fertilizer of broadleaf plants, which are going to dominate this bed.  I also continuing to fight the grass and blackberries in the rose bed.

Fall is a very busy time for me, moving and spreading leaves, and I didn’t get to move leaves from Schroeder Park to the Parks office until November.  I brought silver maple, cottonwood, and sweet gum leaves, about 3 yards in two pickup loads, and piled them generally in an oval shape in the center of the area, but also spread them on what would be the path around it, and in the 8” space between the fuel tanks container and the front fence, to keep the weeds down.  

I wasn’t sure yet what kind of path mulch I wanted, and the director wasn’t there that day to consult.  4 x 8 sand (1/4”-1/8” river sand) would look sharp, but would need regular working with hula hoe and rake to keep it that way.  The other option was to cover the leaves that I spread around the bed with walk-on-fir bark, which would need only yearly renewal.  For the time being, I decided to go with the leaves and bark for lower maintenance.

Our early December snow storm hit before I could return with compost and Rubel blueberry plants that I had been growing from #1 to #2 containers all summer.  At the Parks board meeting in early January, our Director told me that the leaves behind and around the tanks had to move.  That decided me on the 4 X 8 sand with regular maintenance option for the path around the bed and behind the tanks.  One inch is all one needs; more than that and it feels like walking on a beach.

The second Wednesday in January, I brought a yard of compost and three blueberry plants and commenced to raking and forking soggy leaves from the path area and behind the tanks; piling and stomping them in the center oval nice and flat; and making cone-shaped holes in the leaves to set the blueberry plants in.  I followed that with compost around the plants up to the level of the pot soil and all over the leaves, thick enough to hide them pretty well.  I then went to get a load of 6-12 cobble rock (aka Dog Creek Boulders) from Copeland, of a generally flat-bottomed shape and middle size, to hold in the compost.  I wound up 7 feet short of surrounding the oval.

I heard at the Parks Board meeting that people were loving the look of the bed.  People really do love the look of compost and rock borders.  But I wasn’t finished yet.

Two weeks later, I brought a ½ yard load of 4 x 8 sand and enough rocks to finish rocking in the oval.  I brought just enough sand to cover the area around the bed, making a clean walking path.  But there was not enough to cover the area between the fence and the tanks.  That will wait for another couple weeks, when I also crown both the roses. 

It is difficult to see naked blueberry plants, but there are three of them.

I then went to rake up a small load of pine needles along Pinecrest/Plum Tree Lane, where the gravel shoulders catch and hold pine needles, while letting oak leaves blow into the ditch.  I spread about half of what I raked onto the blueberry bed, shaking the needles onto the bed as naturally as possible, and picking out the occasional cigarette butt.  I tried to put on enough to keep it covered the whole year, as top mulches tend to thin out over the summer. 

I took the remainder home and spread them over about half my front yard beds, to cover the maple leaves I had spread earlier to protect my pots and plants before December’s snow and deep freeze.  Pine needles look a lot nicer than big leaf maple leaves, and keep them from blowing around.

I’m not sure yet what ground covers I want to plant to keep the blueberries roots covered and cool.  I’m thinking about small sedum and winter cyclamen.  They are slow growing, but easy maintenance and very pretty and low.  Pine needle mulch will have to be kept fairly thick until they grow in solid.