Horse Manure: Not Guilty, So On To Pruning

    A dark cloud no longer hangs over my horse manure, that is, the horse manure that I occasionally truck over here to add to my compost piles. I wrote a few weeks ago about the possibility of herbicide that, when applied to hay, retains its toxic effect when an animal eats the hay and even, for a long time, after that animal’s manure has been composted or spread on the ground.
    My herbicide residue concerns were soothed with a simple assay that showed satisfactory growth from bean seeds in both hay that was suspect and hay of known integrity. Also, the bedding in the horse manure is mostly wood shavings rather than hay.
    But another ugly dragon kept raising its head above the manure. Another chemical, this time, Ivermectin, a de-worming medication given to horses (and other animals). Ivermectin or its metabolites might pass through the animal and injure soil dwelling creatures such as beneficial nematodes and earthworms. Past studies have shown negative effects on, for example, “dung fauna and degradation of faeces” (to quote a research paper from 2006).
    Ivermectin is, admittedly, a very useful material, even useful in humans to combat lice, bedbugs, and some more frightening tropical afflictions such as river blindness and elephantiasis. Agriculture is always a balancing act, but I like to keep my soil-dwelling partners happy.
    So I was gladdened when a veterinarian recently directed me to a Stanford University publication that summarized research findings on the environmental effects of Ivermectin. To whit: Ivermectin is excreted and it can affect earthworms, springtails, and other fauna. But it degrades quickly at summer temperatures (1-2 weeks, but much longer in winter) and within a day or two of exposure to bright sunlight. With temperatures within my compost bins reaching 150°F., or more, with the compost sitting many months before use, and with the compost being spread on top of the ground, little Ivermectin would end up in the soil. And soil anyway naturally has low levels of this compound.

Snow Makes Me Taller

    Let’s look aboveground, at stems; there’s pruning to be started. With well over a foot of snow on the ground, I turn my attention to taller plants. The snow is actually an advantage because, with snowshoes on, I can reach more than a foot higher into the branches without a ladder.

Sammy (the dog) and I pruning pawpaws

Sammy (the dog) and I pruning pawpaws

    For now, I’m going to start with the easiest pruning, mostly with plants that don’t need regular pruning beyond removing dead, diseased, broken, and grossly misplaced branches. Right here, such plants include pawpaws, plums, cornelian cherries, and a teenage honeylocust tree. Light is important for fruit production from the fruit trees and, generally, to keep diseases and insects at bay, so I also prune away enough branches to let remaining branches bathe in sunlight.
    I go at the pawpaws with one more goal in mind, to keep fruit from forming either too high in the tree or two far out on the limbs. Pawpaw trees will grow 15 to 25 feet high but I harvest fallen fruit from the ground. By my estimation, fruit can make a soft landing, undamaged, from a height of about 10 feet onto mulched ground. So I lop back the tops to weak side branches at about that height.
    Each pawpaw flower is a multiple ovary, potentially spawning up to nine fruits, each of which can weigh more than half a pound. That’s a lot of weight perched onto the end of a branch, so I shorten long branches to decrease leverage of that fruit load.
    (More about all types of pruning on all kinds of plants in my book, The Pruning Book.)

A Beautiful Climber

    I actually did begin pruning a few weeks ago, before the first snow fall. The plant was hydrangea — no, not the common bigleaf hydrangea which has many people scratching their heads about how to prune, but climbing hydrangea (Hydrangea anomala subsp. petiolaris).

Climbing hydrangea in summer

Climbing hydrangea in summer

   Climbing hydrangea is one of the most beautiful vines, even right now as the peeling, pale cinnamon, bark is in focus among the leafless stems. All summer long, the stems are clothed in lustrous green foliage and, in early, summer clusters of white flowers twinkle against that backdrop like stars in the dark sky.
    As expected, the vine took a few years to get firmly established. Now it threatens to engulf my brick home except that I want to restrict it to only the north wall. Every year now, I prune back stems creeping like groping fingers around the east and west walls. And each year the flower stems reach further directly out from the wall, so I also shortened them.

Climbing hydrangea, partially pruned

Climbing hydrangea, partially pruned

    The present pruning doesn’t permanently subdue the plant. This summer, I’ll again shorten the wandering stems, and I’ll be back at it again next winter and for winters to come.


Hay, Grass Clippings, Manure, Leaves — Watch Out!

Organic materials — that is, things that are or were once living — are the core of “organic” agriculture, and right from the get go, many years ago, I set out pitchfork in hand to gather these materials. Into large garbage pails toted around in my van I loaded manure from nearby stables. Neighbors let me haul away their bags of autumn leaves.

I even convinced city workers to dump a truckload of harvested lake weeds onto the side lawn of my small rented house. (That was in Madison, Wisconsin, where fertilizer runoff from lawns was spurring growth of lake weeds which, besides making swimming hazardous, were, upon their death, causing oxygen depletion of the lakes.)

Me mulching, even as a beginning gardener

Me mulching, even as a beginning gardener

Mowings of roadside hay, which I stuffed into the back of the van, were another source of organic matter, used for mulch and for compost. That was before the days of lead-free gasoline, so lead contamination was some concern. Then again, high levels of organic matter in the soil mitigate lead hazards in soils.

More dramatically of concern were bags of grass clippings I once dragged across the yard from my neighbor’s freshly mowed lawn. Hours after I had spread the clippings around my potato’s lush, green vines, their stems twisted and contorted as if screaming in pain — the effect of weedkiller used on the lawn. Perhaps my neighbor was striving for a uniform greensward; perhaps he had inadvertently used a lawn fertilizer laced with weed killer. “Weed and feed” sounds so cheerful and labor-saving. Lawn weedkillers are toxic to broadleaf plants, which means anything but a grass.

The particular weedkiller was probably 2,4-D, also know as Agent Orange (less cheerful-sounding), which is a synthetic category of plant hormone called auxins. At the right concentration and at the right time, whether natural or synthetic, auxins do good things, such as bending plants towards light, initiating root growth in cuttings and in growing plants, and promoting upward growth Otherwise, they can wreak havoc.

I phoned the university extension specialist and was advised to remove the mulch and to adsorb any escaped 2,4-D by mixing activated charcoal into the soil. I did so and subsequent growth was normal.

Home-Grown vs. Imported Hay

I now have the luxury of scything much of the organic material I need from my own one acre field. Early season mowings are succulent and nitrogen-rich, just like grass clippings. Later mowings are hay, dry and carbon-rich. During the growing season, depending on what and when I mow, I can harvest either end of the spectrum, or anything in between.

Wood chips are another good source of organic material, one free of chemicals

Wood chips are another good source of organic material, one free of chemicals

I no longer rely on roadside mowings as organic material for my plantings. They are nowadays too finely chopped for easy and fast scooping up with a pitchfork. Even if that were not the case, I would have second thoughts about bringing such hay on-site. Again, weedkillers are the threat, more insidious these days because of use of more persistent ones. So-called pyridine carboxylic acid weedkillers might hang around in the soil or on sprayed vegetation for anywhere from less than 30 days to several years, even in the manure from animals that have eaten sprayed vegetation!

Caution, Testing, & Time to Avoid Problems

I do still occasionally supplement home-harvested organic materials with imported ones. One source is horse manure from a local stable.

A few weeks ago I was pitching forkful after forkful of manure into the bed of my pickup truck when I glanced over at the far side of the pile and noticed some discarded hay, much of it still pressed together in partial bales. “How convenient,” I thought, for mulching, compost, or bedding for my chickens and ducks.

On my drive home I started thinking about that hay riding behind me. Could it be laced with weedkiller?

For the most straightforward answer, I could just ask the stable owner. A stable hand told me that the hay had been shipped from a few hours away. Rather than cross examine my manure donor, I looked closely at the hay to see if any clover, alfalfa, or other broadleaf plants were mixed in. No. Of course, lack of broadleaf plants does not prove that weedkiller was used.

Well-formed leaves indicate that the hay is free of chemical residues

Well-formed leaves indicate that the hay is free of chemical residues

My final recourse was to do a bioassay of the hay, essentially, to plant seeds in it and observe their growth. Two 4-inch flowerpots, one with chopped up, homegrown hay and the other with the chopped up, imported hay, served as growth media, into which went 3 bean seeds each. Long story short: Growth seemed normal in the imported hay although germination was slower, probably because its texture lent itself to more readily drying out.

To put my mind thoroughly at ease about the hay, I’m going to let the pile sit for a few months, where rain, sun, and, eventually warmth, can do their job in splitting apart the insidious weedkiller molecules. The hay is not for my compost, in the dark innards of which weedkillers, if present, would be particularly persistent.

Autumn Leaves, Good Stuff

Just like the old days, I do still import organic materials in the form of bagged autumn leaves — except a lot more these days. They are both weed- and weedkiller-free.

New Video from Last Summer: Grape Training & Pruning

If you’d like to join me on a brief journey back into summer, see for a new video, I made last summer, about how to prune that quintessential summer vegetable, tomatoes, just like the Godfather.

Propagating Cuttings, Quackgrass

Ten weeks ago I wrote of the “pot in pot” propagator that I was using to root dormant fig and mulberry cuttings. The propagator is nothing more than a small, porous, clay pot filled with water and with its drainage hole plugged that I plunged into the mix of peat moss and perlite that filled the larger pot. Water drawn out of the small pot keeps the peat-perlite rooting mix consistently moist.
The cuttings have sprouted with enthusiasm. And when I lift out the small pot, I see roots running around in the moist rooting mix, so I separated the plants and potted them up individually.
No need to put the propagator away now that plants are no longer dormant. With a simple covering to maintain humidity, the propagator also works well for so-called softwood cuttings, that is, cuttings that start out with leafy shoots. Technically, today’s new cuttings aren’t “softwood” because they haven’t had time yet to begin much growth. They could more accurately be called “leafy.” Their first leaves have unfolded and shoots (the “softwood”) are soon to appear. Whether “leafy” or “softwood,” such cuttings need high humidity to keep leaves from wilting until roots develop.
The propagator conversion involves nothing more than poking four sticks into the rooting medium equally spaced around its outer edge, and then draping a plastic bag over the sticks. Bright light will keep the green leaves feeding the cuttings. Direct light is a no-no because it would cook the cuttings in their high humidity chamber.
I suppose I could be nostalgic about the quackgrass (Elytrigia repens, and also commonly called witchgrass and couchgrass) stealthily making inroads into my various gardens. After all, quackgrass was my first serious weed problem in my first real garden, a vegetable plot of about 500 square feet in Madison, Wisconsin. At the time, the lakes in Madison were suffering their own weed problems, the result of “fertilization” of the water with runoff from over-fertilized, residential lawns surrounding the lakes. Giant beaters plied the lakes in those days, chopping the lake weeds which were then harvested onto boats and then trucks for disposal. “Weed-free mulch!,” thought I. 
I convinced a lake weed crew to dump a truckload of those water weeds onto my front lawn. I spread the mulch quickly — I had to because the soggy mass started rotting within a few hours to what was beginning to smell like a a pig farm. Laying pitchfork after pitchfork of the stuff between rows of vegetables spelled quick death to the quackgrass.
My gardens now are far more extensive, no straight expanses beckon easy mulching, and water weeds are not in the offing. So for now, I am attacking quackgrass mano a mano, digging and pulling out every last shoot that I can find along with attached, running roots — no easy task among perennial flowers. Where I can, I’ll spread a few sheets of newspaper and top that with mulch. Now is the time to attack because in about a month, new runners will begin to push further afield just beneath the soil surface. The pointed ends of these runners are sharp enough to push right through a potato.
Quackgrass is so widespread that you’d think it was native. Not so. But it has been here for a long time, coming over from Europe with the first colonists. And it’s not all bad: It is good forage for horses and cows, and has been used in herbal medicine especially for kidney ailments. “It openeth the stoppings of the liver,” according to 16th century herbalist John Gerard. Still, it’s not welcome in my garden.
I’ve got one more deathly arrow in my quiver with which to fight off quackgrass, but it must wait until the weather warms. Vinegar. Household strength vinegar sprayed on the plants kills the leaves; repeatedly killing the leaves eventually kills the plants. I boost vinegar’s efficacy by pouring 1 tablespoon of Ivory dish detergent and 2 tablespoons of canola oil into each gallon of vinegar. Vinegar works best when temperatures rise above 70° F.