Locally sourced and great

There’s a new pile of wood chips in the driveway. After a heavy wind brought down some big pine branches in the yard, arborist Kevin Newman recommended thinning the crown of our tallest pine. His team left me the resulting chips. 

I'm gradually transferring wood chips from the driveway to the garden

    Now is a great time for spreading wood chip mulch. On warmer days, I’d like to be outside doing something in the garden, but nothing’s growing. That’s when I load up the wheelbarrow with wood chips and trundle around the yard to dump them where they’re needed.

    After working with this mulch for eight years, I’m a huge fan. It’s a sustainable choice, because the chips originate in my own yard or nearby where Kevin’s men are pruning or taking down trees. The chips are easy to work with, much less dense than bark mulch. 

A wheelbarrow full of wood chips isn't too heavy to maneuver

Unlike bark, they don’t contain wax, so they don’t block water from soaking into the soil. The first time I dug into the soil under the wood chip mulch, I was amazed. It’s dark, moist and rich—just what a gardener hopes for.

    This year I’m spreading wood chips around trees and shrubs, and I plan to add some to the garden paths, where they break down fastest because of heavy foot traffic. If I do more sheet composting, they’ll be a key ingredient.

Sheet composting March 2019: wood chips on top of composted cow manure

    My source of mulch information is Linda Chalker Scott, a horticulturist and mulch scholar at Washington State University. She corrects conventional wisdom with scientific fact. For example, people worry that wood chips will acidify soil. Research shows they don’t. I’m increasingly aware that soil is not an inert substance. It’s full of biological and chemical activity, including an effective buffering system. You can’t change the pH of soil without adding chemicals such as lime to make it more alkaline or sulfur to make it more acid.

    There’s a gardening legend that high carbon mulch such as wood chips depletes nitrogen in the soil. Linda studied this and found no evidence for it. She hypothesizes that there’s a narrow band of relative nitrogen deficiency at the interface between the soil and the wood chip mulch. This is actually a plus, because it suppresses weeds. You can use this mulch anywhere in the garden except where you’re going to plant seeds or young annuals that don’t have an established root system. Like young weeds, they’d suffer in this nitrogen-poor zone.

Wood chip mulch will suppress weeds around this tree

    Can chips from diseased trees infect your yard? This is a concern I often hear from garden club members. It turns out not, because the disease organisms in mulch can’t reach plant roots. I often see impressive networks of white fungal hyphae among the chips, either in the pile or after they’ve been on the ground for a while. Linda Chalker Scott explains that these fungi are decomposers, not pathogens. With their help, wood chips decompose slowly, gradually releasing nutrients our plants’ roots can use. I’m grateful to have this free material for pampering my plants and soil.

Sheet composting begun

Blood meal came in the mail (sounds ominous, doesn’t it?), enabling my grand-dog Felix and me to start the sheet composting project. As you’ll remember, this is a technique for converting some lawn to expand a planting bed. We’d be applying layers of compostable materials to smother the grass and make rich soil for new native plants.

Purple coneflowers will be able to spread into the enlarged bed

    The first step was to mark off the grass section for execution. I did this using short stakes and some stretchy orange plastic surveyor’s tape. I can re-use the tape when this project is finished.

    After moving the stakes around to see how the edge of the new bed would look, I settled on a straight edge parallel to the nearby rectangular vegetable bed and 10 feet from the rabbit fence that protects that area. The ends of the new bed would curve into existing planting areas.

Orange tape marks the edge of the future planting area

    Next I sprinkled a dusting of blood meal on the grass and followed it with layers of newspaper. To pile them several sheets thick, I had to combine sections of the paper, overlapping them so no grass was showing. I avoided glossy supplements that might contain problematic inks. The paper wanted to blow around in the spring breeze but subsided with a generous sprinkling from the watering can. I laid down newspaper in three stages, weighing it down with the next materials before moving on so that the paper wouldn’t dry out and blow away.

I watered the newspaper to keep it from blowing away

    On top of the newspaper I spread a layer of composted cow manure. I had two bags left over from last fall, both open. Some of the contents were frozen, and I couldn’t break them up. I stood the icy parts in the sun to melt. 

Cow manure popsicle warming in the sun against the rabbit fence

In all, it took most of four 50-pound bags to cover the 120 square foot area with an inch of cow manure. I was treating the sheet composting recipe more like instructions for a stir fry than a fine pastry—just adding what looked about right.

A section of newspaper covered with cow manure

    Admonishing Felix not to dig through the manure-covered newspapers, which seemed to be an alluring possibility, I next turned to hauling wood chips from the big heap in the driveway. After many wheelbarrow trips, I’d dumped an 8-inch layer on top of the newspaper. 

Wood chip layer

I added a few inches of fall leaves that I raked from nearby beds, anchoring them down with more wood chips. That’s where the project stands as of Saturday afternoon: a long foot-tall mound of compostable layers, widest in the middle and tapered at both ends.

It doesn't look like much now. Give it two years.

    The next stage will be to pile on a layer of compost, which will boost the population of soil organisms to start the decomposition. The icing on the cake will be a topping of weed-free straw.

    Moving the wood chips wore me out, but the initial investment of time and energy seems like a small price to pay for what should become an area of great soil in a couple of years.

Smothering some lawn

On Friday Kevin Newman’s team did some long-overdue pruning in my yard. They cut out dead branches, pruned back our trees where they were hanging over the fence, and removed branches that had grown over our property from next door. They fed all the branches into the big chipping machine parked in the driveway. Before they left, they carefully dumped a portion of the chips in front of the garage.

A new trove of wood chips

    This puts me right where I want to be. I’ve got big plans. I’m going to add a big swath to one of the shrub and perennial beds by trying out sheet composting.

    The spot I have in mind is some lawn in front of the dawn redwood (Metasequoia glyptostroboides). When we planted the tree in 1997, it was slender and just 10 feet tall. Now it’s rooftop height and wider every year, with feathery branches overshadowing the perennials I planted around its base. By commandeering some of the lawn in front of this bed, I can grow plants that need more sun than they can get under the tree’s branches. And I can forward my mission to subtract lawn.

Now covered with snow, this patch of lawn doesn't know what's about to hit

    My planting plan for the new part of the bed is still vague. I’m picturing low native plants. I’ve got time to study my ecoregion’s plant community to decide what these should be. The flower color scheme so far has been blue and deep pink. I’ll try to harmonize with the dusky pink blooms of a growing patch of purple coneflower (Echinacea purpurea) at the front of the existing bed.

What goes with purple coneflower?

    Sheet composting is the same process that happens in compost bins, but spread out over a wider area. 

Master Gardener Eve Werner, Butte County, CA, demonstrates sheet composting over lawn

The technique I’ll use is adapted from Toby Hemenway’s permaculture book Gaia’s Garden. Usually I skip recipes for “lasagna composting,” because I can make compost more easily by dumping plant waste on the compost piles as it comes. This time, though, I’m going to try the recipe to speed things up. If I just put down a layer of wood chips and fall leaves, they’d take years to decompose.

Wood chips on paths decompose very slowly

Here’s the recipe from the ground up:

1) A thin layer of blood meal for nitrogen (Blood meal powder is a byproduct of slaughterhouses. It appeals more to me than a high-nitrogen chemical fertilizer, which could leach nitrogen into the groundwater).
2) A layer of newspaper, minus glossy supplements, an eighth to half an inch thick, to smother grass
3) Composted manure for more nitrogen 
4) Twelve inches of wood chips mixed with fall leaves
5) A couple of inches of compost to inoculate the pile with soil organisms
6) Two inches of clean straw that’s free of weed seeds

    It’ll take a couple of years for soil organisms to weave through these layers and convert them into rich soil. I can plant seeds and seedlings this year in pockets of compost. 

Tomatoes planted into sheet compost-photo Natureln

Bigger plants will wait until next year. Meanwhile I can gloat over the lawn decomposing underneath.

Mulch falling from the trees

My new perennial bed near the back of the house is covered with needles from a big white pine (Pinus strobus) nearby. 

Pine needles on the new bed in October

When the area was lawn, I didn’t notice how many needles fell from the tree, perhaps because our focus was on raking them off the grass.

    Now I realize that those pine needles are providing natural mulch without my intervention. Is that a good thing? A couple of persistent urban legends warn against pine needle mulch.

    In the South, you can buy compressed bales of pine needles, commonly called pine straw, in various shapes and sizes at the garden center. 

Bales of pine straw at Space Coast Landscape Supply in Florida

Proponents point out that this mulch is pretty, it’s slow to decompose because of the needles’ waxy coating, it doesn’t blow around or pack down to create a water barrier, and it’s less dense than bark mulch. A 40-pound bale of pine straw covers as much ground as 30 cubic feet of other much heavier mulches. By contrast, big bags of bark mulch that I purchased recently contain 3 cubic feet each. I can barely lift them, and a bag covers a dishearteningly small area.

Bark mulch, heavy as all get out

    Tossing pine needles around has got to be easier than schlepping those bags of bark mulch. Having the tree and the wind spread pine needles is even less work. (My recent mulch favorite, arborist wood chips, also has the advantage of being less dense than bark).

Arborist wood chips make great mulch too

    It’s often suggested that pine needle mulch will acidify soil. The argument is that since the needles have a lower pH than average soil, adding them to soil must make it more acidic. Many gardeners hesitate to mulch with oak leaves for the same reason. But science doesn’t substantiate this.

    Soil has tremendous buffering capacity. As Robert Pavlis points out in this blog post, rain becomes acidic as it falls, picking up carbon dioxide from the air and converting it to carbonic acid. This is true even without the pollution that causes acid rain. If rain hasn’t changed soil pH over millennia, you’re not going to do it with a few pine needles or oak leaves.

Pine needles can't overpower soil's buffering capacity

    Second, pine needles contain a group of organic compounds called terpenes that people worry may suppress growth in the garden. Terpenes act as insecticides, preventing insects from eating the needles. They may also help suppress growth of other plants under the tree. But once the needles fall from the tree and hit the ground, the volatile terpenes quickly float into air or water—that’s why the needles stop giving off that pleasing pine scent. Plants can and do grow under our white pine.

Shade lovers growing at the base of the white pine

    Recent research suggests terpenes help trigger rainfall by combining with free radicals and oxygen in the atmosphere, forming aerosols of polarized molecules that collect water and grow into clouds. Trees aren’t as passive as we used to think!

Conifers don't just wait for rain

    I’ll soon be able to assess whether pine needles are improving soil, suppressing weeds, and helping to retain moisture in my new bed. I’m optimistic.

Planting party

What a week! On Wednesday, Kevin Newman’s team finished work on my yard. They left me with two new beds filled with beautiful black loam, ready to be planted. On Friday I set out on a shopping binge, and now I’m shuffling the plants around, designing the new plantings. Chances to plant a whole new area come along once in a decade. I’m having a blast! 

Trying out arrangements of new perennials for sun and part shade

    The first stage of the renovation started Monday morning, with the men rapidly scraping away the lawn around the deck. In a couple of hours, the grass was gone. Then they cut down five hemlocks at back corners of the lot (more on this in a future post), dragged the pieces out to the chipper parked in the driveway, and reduced them to wood chips. They returned the chips to the yard, using them to cover two new paths. 

Wood chip path for trundling wheelbarrows

Paths made from our own wood! You can’t get more sustainable than that! [note the presidential punctuation].

     The longest phase involved the heavy work of lifting large bluestone pavers from around the deck and putting in a new stone path leading toward the garden.

    What’s going into the new beds? They’re partly in sun, which means a chance to grow flowers that can’t thrive in most of the garden because it’s too shady. I had so many perennial darlings on my wish list that the problem was to pare it down. One of everything is not a good design principle. 

    I was looking for plants that stay low, so they won’t block the view of the garden from the deck. I thought back to a successful bed that designer Betsy Brown created for us in 1994 for a hot, dry west-facing spot. This time natives were a priority, but I couldn’t bear to leave out a few imports that had been stars of Betsy’s design.

Lady's mantle (Alchemilla mollis) had to be included--photo by Anneli Salo

    So far here are some high points of what I’ve chosen: For the sunniest area, Achillea ‘Coronation Gold,’ a yarrow with gray foliage and flat yellow flower heads in a subtle shade of yellow, 

'Coronation Gold'

an elegant St. John’s wort (Hypericum ‘Magic Universe’) with golden flowers, dark red fruits, and foliage with tones of red and blue, 

St. John's wort fighting off depression

prairie dropseed (Sporobolus heteroleptus), a native grass that will contribute panicles of pinkish-tan flowers in late summer, and a low-growing blue juniper (Juniperus squamata ‘Blue Star’) for winter interest.

     For the partly shaded section, a few I have high hopes for include the red-gold flowers of sneezeweed (Helenium ‘Short ‘n’ Sassy’), 

A similar sneezeweed--photo by Dietzel

a nice goldenrod (Solidago odora), and some blues in the form of Stokes aster (Stokesia laevis ‘Blue Danube’) and Canadian phlox (Phlox divaricata ‘Blue Moon’). Among these I have a chance to intersperse some of my favorite ground covers: bearberry (Arctostaphylos uva-ursi), wintergreen (Gaultheria procumbens), and a multi-colored bugleweed (Ajuga reptans ‘Burgundy Glow’).

Gaultheria procumbens does well in part shade

     This is just the first pass. Stay tuned for the editing process.

Less lawn in 2017

Although there’s snow outside my windows, plans for the 2017 garden are swirling in my head. One gnawing issue is the lawn around the deck. It mostly doesn’t exist. 

Spring photos and avoiding looking straight down help disguise sparse lawn grass

     It’s tempting to imagine that this time I’ll really work on that lawn, improving the soil with compost, reseeding, and pampering the new grass with frequent watering. It’s never happened before, but this could be the year. 

     To be a sustainable gardener, though, I resolved NOT to pour resources into lawn grass. Mowing, fertilizing, and extra watering all make lawns environmentally undesirable.

Just about any other plantings are more environmentally sound than a lawn

     Last year I became aware of a major problem for this supposed grassy area—me. I walk over it constantly on my way between the garden, the house, the tools in the garage, and the compost piles in the utility area. The soil is well and truly compacted. What’s to be done? 

Clover, dandelions, plantain, and crab grass predominate in the compacted lawn

     Now that I think about it, the neighbors who maintain lovely lawns stay off them. But not walking on this section of my yard isn’t an option. I could aerate the soil, but my footsteps would soon pack it down again. I could replace the whole lawn with gravel or stone pavers. I don’t want to take on the never-ending job of keeping soil and weeds out of gravel, though, and paving the whole section seems excessive, as well as expensive.

Gravel is kept clean in this British garden. They make it look easy.

    I considered an approach I’d have thought completely philistine until recently—artificial turf. In 2014, my sister-in-law Jennifer Gilbert Asher, a garden designer and sculptor in Los Angeles, tore out the lawn around her swimming pool and replaced it with recycled artificial turf. Her reason was southern California’s longstanding water shortage. I thought she was heroic, but I still couldn’t see it for New England. That was before the Northeast’s 2016 drought.

    This month I noticed some good-looking green grass around a building owned by our electric utility. I’d walked by the place many times and never recognized that the lawn was artificial. I can see why it fooled me, because the “grass” is deep green, soft, and doesn’t look plastic. 

Artificial turf in Florida. It looks a lot better these days.

     Jennifer laid her artificial turf on a layer of sand, which I think means that her lawn doesn’t include the toxin-containing “crumb rubber” layer that’s used in artificial athletic fields. Of course, it doesn’t require mowing, watering, or fertilizing. 

     There are negatives, though. Artificial turf doesn’t provide the animal habitat offered by a natural lawn. It might heat up uncomfortably on summer days. When it came time to remove the polyethylene artificial turf, it probably wouldn’t be recyclable.

    Jennifer replaced her front lawn with a thick layer of arborist wood chips. That might be my best option for the area around the deck. I could replace part of the lawn with low-growing perennials and make some wide wood chip paths to get me where I need to go. 

More wood chip paths could be a solution

Then I could stop feeling bad about this pathetic grass and focus on plants that are more fun.

Coming soon--spring bulbs

Time for wood chips

With spring almost in the air, I asked my neighbor Kevin Newman to drop off some wood chips from his arborist business. Kevin and his men came over and carefully dumped a moderate pile of chips in the driveway. 

Three years ago they brought a whole dump truck’s load, and it made a pile almost too huge for me to deal with.

    I got the idea of using wood chips as mulch from reading Linda Chalker-Scott, known to her admirers as “the Mulch Queen.” She is a professor of urban horticulture at the University of Washington at Puyallup and a myth-buster who applies scientific principles to conventional wisdom in gardening. She and colleagues blog at The Garden Professors, which is a great source of unembroidered horticultural truths.

    Chalker-Scott has reviewed the scientific literature on mulch and conducted her own experiments. She recommends arborist wood chips as the best mulch of all. 

     Before trying the wood chips, I was happy with the mulch I made from fall leaves. I never have enough for the whole yard, though, and the leaf mulch decomposes fast, mostly melting into the soil within a year. 

I was still supplementing this homemade product with bark mulch I bought at garden centers or Home Depot.

    The wood chips are superior in several ways. First, they’re free. Kevin is willing to give them to me; otherwise he’d pay to dispose of them. Second, they do impressive work building soil. I was amazed when I first dug through a layer of wood chips to plant some native Allegheny spurge (Pachysandra procumbens) in a shady area under a line of trees. The soil under the mulch was rich, black, moist, and easy to work. When I’ve dug under bark mulch, I’ve sometimes found the soil dry and hard, possibly because the wax in the bark can prevent water from penetrating the mulch layer. 

     Another good feature of the wood chips is that they’re easy to handle. A wheelbarrow full of chips is much lighter than an equivalent volume of bark mulch, which is so dense that I can barely heft a bag from my car to the wheelbarrow.

    The look of the chips is an acquired taste. I found their blonde color jarring when I first laid them down. Now I’ve gotten used to it, and I know that over a few months they’ll fade to a less conspicuous gray and later to brown.

A path of aged wood chips

    So I’m spending this weekend shuttling back and forth with my wheelbarrow, adding a new layer of wood chips to my garden paths. The next priority will be the berm at the back of the yard, where they’ve been enabling water to soak down to the roots of mature evergreens that screen us from our neighbors (The only place not to use the chips is around vegetables and annual flowers). 

     It almost feels like the gardening season has started!