Bark Blowing, Mulch, Barkdust: pros & cons

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Benefits of barkdust and mulch can't be overstated. I recall an experience years ago, in Beaverton by Portland, Oregon, when we planted about 30 Rhododendrons under some Douglas Fir trees. We were planting in an area where there was just exposed soil.

We expected that it would be easy to keep Rhodies moist, even if weather was nearly 80 degrees for 3 weeks straight - all we needed to do was water. But each day. the plants wilted, and wilted more, and then more. Finally, we acquired one pickup truck bed load of bark mulch, and laid down a 5' wide circle of that shredded bark around each plant, about 1” deep.

In only one day, the leaves perked up to the healthy condition seen on the day of purchase. In one week there was new growth - new leaves and shoots.

The clay soil around the planting holes that was like a brick from lack of moisture, could now be penetrated with a shovel relatively easy. The barkdust promoted new plant growth and good soil conditions.

This is related to what happens when some rain forests are stripped for farming, but rendered useless as soon as the soil dries out. Soil benefits from shading, and garden bark mulch provides that. And other types of organic mulch.

Bare soil will be compacted by rain drops. Rain hits, compacts the top soil particles, and causes more erosion. Bark, mulch and cedar chips take the impact and protect the soil layer below. This is especially useful for cities near Portland, Beaverton, Lake Oswego, Eugene, Salem, Brookings and Seaside in Oregon, which receive a lot of rain. Vancouver and Seattle are very similar, as is Vancouver, B. C..

The city drains in all of those cities can be spared excess rain water, if residents avoid exposed bare soil by adding layers of mulch and barkdust.

Barkdust reduces compaction from rain, reduces erosion, shades roots, holds moisture in a way that words almost can't convey, insulates roots and soil from freezing temperatures, and, it looks good.

Bark is also useful for tree root preservation at construction sites. If thick layers can be placed around the drip line of trees, the bark reduces soil compaction from activity if the area can't be fenced-off.

The presence or absence of a decent layer of barkdust or mulch will frequently make or break the success of newly planted trees and shrubs.

Barkdust and mulch, leach-out compounds that improve the structure of soil. This increases the movement of air, moisture and beneficial microorganisms in the ground.

First, bark blowing companies have a good service to offer. But the bark and mulch service must be offered and performed ethically and honestly. That includes more than just how many cubic yards of fir, hemlock or cedar chip you will receive.

The best aspects about powered blowing of barkdust:

1. Bark can be blown on some steep slopes much easier than manual application, especially if the bark must be applied from down below, to the slope up above.

2. It is much faster in many cases to apply barkdust in a remote location like a back yard. Somtimes it is easier to wind a bark blowing tube through a slim gap, than it would be to force a wheelbarrow through.

3. An experienced bark blowing operator can apply bark over certain ground covers more efficiently than a worker using a wheelbarrow, shovel or pitchfork.

Blowing machinery can also apply chips to playgrounds, soil mixes to landscape areas and various mulches as needed.

Don't be deceived if a bark blowing company claims that blown barkdust reduces the needed amount of product. That is not true. If we need 2” of mulch or barkdust, then we need a 2” layer. It won't matter whether the bark is blown on with a blower or spread by wheelbarrow and shovel – we need 2”.

In fact, the use of a bark blower may increase the amount of product needed. If you ever get a chance to watch a bark blower, pay attention to how much of the fine particles float in the air and land on other houses, cars and in remote areas. These finer particles would be the first part of the mulch to decompose and amend the soil if those did not fly away in the air.

Manual spreading of barkdust prevents the loss of fine particles. Manual spreading is the means by which less product will be needed when compared to bark blowing. Don't let this discourage you from hiring a bark blowing company, but this is to set the record straight regarding potentially false claims by bark blowing companies.

Another misleading statement about a bark blower application is that weather conditions do not restrict it. Let's think about that one. If a wheelbarrow was rolled across a saturated lawn to move barkdust, that could be bad for the lawn. The hose of a bark blowing operation does minimal damage to drenched turf, and can move the bark to the destination without leaving muddy ruts in the grass and other areas.

But, if the weather is wet and rainy, there will be fine barkdust caked all over the leaves of plant and trees. It will stick to the moisture on the leaves, and additionally, the bark can stick to wet siding on houses, wet patio furniture and wet automobiles. In dry weather, strong wind can blow fine bark onto your neighbor's cars and even into their open windows. Bark blowing is a very dusty operation when the wind is not blowing. When the atmosphere produces strong wind, barkdust blowing is very, very messy. So weather can drastically affect whether or not bark should be blown on your landscape.

Bark blowers may promise a smooth and consistent “finish”. In general, that is true for most of the exposed flat surfaces of the ground. But in most cases, the bark that is blown accumulates in small piles against the trunks of shrubs and trees. Bark should not be piled against tree bark. If bark is in a heap against a trunk after blowing, it should be removed or smoothed. In most cases where I have seen bark blown in a landscape, the workers have not removed bark from against shrub and tree trunks. The workers have blown the messy fine barkdust particles from sidewalks, but not the trunks.

If you tend to hire professional window cleaning services to wash and clean your windows and screens, consider using bark blower services only for special needs. Bark blowing impregnates screens with particles and the fine barkdust suspended in the air lands and accumulates in the window tracks. Fine particles can be seen adhering to window panes too, after a bark blower company is through.

Barkdust blowers do apply a smooth finish, but not smoother than manual application in most routine landscape situations. If the back side of a metal leaf rake is used to smooth bark, it will look every bit as nice as barkdust blown on with blower machinery.

To wrap this up:

Bark blowers and manual application of bark both have a place. My suggestion is to use bark blowing for steep slopes, inaccessible areas, remote areas and where wheelbarrows or machinery with wheels would cause soil damage or an extensive mess. But for most barkdust application needs in the landscape, manual application and spreading will retain and save more of the bark product and keep windows and surrounding surfaces cleaner. In addition, manual spreading is done slower, allowing more opportunities and time to make sure that bark is not heaped against tree trunks. Manual application – done slower – allows the workers to pay attention to much more of the landscape situation

Usually, I don't recommend rubber or synthetic mulch. These don't leach as many useful compounds, and may give off pollutants after a period of time in the sun and weather. On the other hand, I don't rule out any product altogether. Certain materials can fit special needs.