Mulch
Mulch refers to any material applied over the soil surface, from bark and wood chips to plastic or paper. Unlike soil amendments, which must be mixed into the soil, mulches stay on top and serve a different set of functions—protecting soil, improving plant health, and enhancing visual appeal.
Mulch is a critical part of landscape care. Choosing the right mulch depends on the effect you want—whether it’s moisture retention, weed control, or simply a cleaner, more polished look. Here’s what to consider:
Visual Appeal
Let’s be honest—mulch makes a garden look finished. Like framing a picture, it ties everything together. While looks often drive the choice, remember: appearance is just one piece. Pick two or three mulch types you like visually, then compare their practical benefits before deciding.
Weed Suppression
Blocking weeds is a top reason to mulch. Some mulches are more effective than others, especially those that create a strong barrier—like black plastic. While not pretty or eco-friendly, it’s widely used on farms because it works.
More sustainable options include thick layers of coarse bark or wood chips. Our mulches are made from clean urban wood or forestry byproducts—attractive, biodegradable, and environmentally sound. While not as aggressive as plastic, they suppress weeds well and support soil health.
Still, some weeds can break through, like oxalis or rhizomatous grasses. Oxalis, in particular, stores energy in bulbs that let it push up through most mulches. The best time to pull them is during mid-winter when bulb energy has been depleted during the formation of new shoots.
Although mulch helps suppress weeds, expect to do some weeding. Weeds are tenacious, spreading by seed, roots, rhizomes, and more. Mulch will reduce their numbers but not eliminate them. Typically, weedy plants that reproduce from roots, rhizomes, and bulbs are the most difficult to control and often require removal by digging them out.
Moisture Retention
Mulch helps soil retain moisture, especially in dry, hot climates. Bare soil heats up fast, dries out quickly, and loses water to wind and sun. A mulch layer insulates the soil, keeping temperatures lower and reducing evaporation. It also provides a vapor barrier that holds moisture in the soil.
Combined with drip irrigation, mulch can dramatically reduce water use. Even with overhead watering, mulch reduces the need to water as often. However, mulch can absorb water from overhead watering and release it back into the atmosphere before it enters the soil, essentially wasting this water. Some mulches absorb more water than others.
Protecting Soil Structure
Good soil is crumbly, not compacted. It’s made of small and large aggregates that allow air and water to move freely through it. When soil is left bare, sun, rain, and foot traffic break the aggregates down, leading to crusted, compacted soil. In severe cases, this can lead to water puddling during rains or irrigation. A sigh that water is not moving into the soil. The reduction of air movement into the soil is less visible but also damaging to root systems. Plants do not grow well under these conditions. It is not uncommon to see stunted shrubs showing little growth year after year in exposed soil areas. Even weed growth can be inhibited.
Mulch prevents these problems by protecting the soil’s surface, preserving the crumb structure, and allowing the essential movement of air and water through the soil. It is a role of mulching that is often overlooked, although it is one of its most important functions.
Fir Bark 3/4”
It is our largest bark of the nugget form. Coarse chunks with few fines, giving a bold, nugget-style look. Fresh bark has a reddish hue that weathers to brown and eventually a gray-brown. If spread at a 3” depth, it will provide decent weed control, good soil protection, and improved water retention. Water will pass through the open structure of the mulch, so not much will be lost by absorption and evaporation from the mulch.
Fir Bark ½”
It is only slightly smaller than the ¾ inch but appears smoother, more uniform, and more natural. It also packs tighter and is slightly better at weed suppression at any given depth than the coarser fir bark. It provides decent weed suppression when spread at a 2 to 2.5-inch depth. It also means it is slightly more cost-effective. It probably retains more water during overhead irrigation than the ¾-inch bark, but since it can be used at less depth, the total absorption is perhaps about the same. More fines are present in this bark than in the ¾ inch, which helps it bond to the soil surface, stabilizing the soil’s crumb structure.
Fir Bark 1/4” +/-
This bark is a blend of sizes averaging about ¼ inch. The advantage of this bark’s size is that it effectively covers and binds to the soil surface. It is excellent for protecting crumb structure and enhancing soil over time. If the soil has a hard surface, it should be raked first, or the surface should be broken before adding the bark so it can intermingle with the roughened surface soil, leading to an overall improvement of the soil. We recommend adding some fresh bark each year. After the winter rains, use a rake or your tool of choice to work the old bark into the soil, then place the new bark on top. Doing this annually will significantly improve soil structure.
The 1/4 +/- bark is effective when applied at approximately a 2-inch depth. This dense covering helps keep many weeds at bay, and greater depth can provide additional benefits. The bark can be easily spread around plants that are already growing in more densely planted areas. We consider this a “gardener mulch” because it can be used at various depths and mixed into the soil at any time throughout the year. It is ideal for enhancing soil tilth and can be seen as both a mulch and a soil amendment. Keeping a bag or two at home will be convenient when working in the garden.
Cottage Garden Mulch
This mulch is similar in size and use to Fir Bark ¼ +/-. The major difference is that it is darker and more closely resembles the color of good soil. Many people prefer the more earthy appearance, but both have their fans. The reddish brown of FB ¼ +/- is a lovely fresh look, but it eventually loses the reddish color and never becomes as dark brown as Cottage Garden, which blends beautifully with soil and complements plantings. It keeps its color well, even when dry. Great for detailed planting areas or open beds where appearance matters. Also effective at improving soil when mixed into the top few inches.
Forest Floor Bark
Forest Floor is one of our most popular mulches. It’s made primarily from fir bark in various sizes, from very fine particles to chunks over 2 inches. This blend mimics the natural duff layer found on a forest floor—hence the name.
Forest Floor does a great job suppressing weeds when spread to a depth of 3 to 4 inches. The finer components of the mulch integrate with the soil surface, protecting and improving the underlying crumb structure. This allows for better air and water movement in the soil—which is key for healthy roots. It’s an excellent option for large open areas but works well in smaller ones.
It’s an excellent choice for moderate slopes because it holds together better than most bark mulches. Its natural look also blends seamlessly into the landscape—more subtle than large nugget barks or coarsely shredded mulches.
Shredded Redwood Bark (Gorilla Hair)
Highly fibrous, lightweight, and fluffy, Shredded Redwood Bark is great on slopes where other mulches may have trouble staying in place. It is also good at weed suppression when spread at 4” depth. An occasional oxalis will make its way through the fibrous maze, but many will not. It is very effective in hot weather, keeping soil cool, and aids in conserving soil moisture. Shredded Redwood Bark does not last as long as other barks. The fibers become compacted during the second year and the bark becomes very flat by the end of that year. At that stage it is no longer effective at weed control.
It is not as useful at maintaining soil structure as fine fir bark, but it is excellent as insulation to keep soils cool during very hot weather. It is also very effective in protecting soil moisture. Works well in open beds but may allow tough weeds like oxalis to break through.
Shredded Cedar Bark
Similar to Redwood but less fibrous and more compact. This denser structure makes it slightly better at weed control. Still good on slopes but may restrict water flow slightly if spread too thick. Supply can be inconsistent depending on timber market conditions.
Redwood Wood Chips
Redwood Wood Chip Mulch is precisely what the name implies. Scraps wood remaining after the milling of redwood lumber are chipped into pieces ranging from about 1 to 1.5 inches wide, and slightly longer. The chips vary naturally in color, from light to dark, and will gradually darken with age. The chips are very clean and devoid of finer particles and soil.
They work well for weed suppression if applied at a depth of 2.5 to 3.5 inches. This is also a good depth for moisture retention. This mulch helps insulate the soil and keep it cooler during hot weather. It can also be used to create simple, mud-free walking paths or as a cushioning layer in playgrounds. A depth of 3 to 4 inches is recommended for paths and playgrounds.
Black Chip Mulch – Narrow
Narrow Black Chip Mulch is made from clean, recycled lumber and cutoffs. It is colored with natural, nontoxic black pigments. The chips are long and narrow, about ½” by 2”, which helps them interlock and stay in place on gentle slopes.
This mulch is an excellent option for small garden spaces as well as more extensive areas. Its deep black color contrasts nicely with the plant foliage, and its color holds up well over time. It stays in place, rarely shows footprints, and is less likely to be disturbed by pets or wildlife than the broader black chips, which often get scattered.
It can be applied as a thin layer of 1 to 2 inches for basic coverage or slightly thicker for enhanced weed suppression. Generally, there’s no need to use a thicker layer. If you are mulching a large area, you may want to buy a bag to play around with to determine your preferred depth.
Arbor Mulch
Arbor Mulch is a locally produced mulch made from the larger wood parts of urban trees. It excludes leaves, fine twigs, and brush. It is comprised of long and narrow hammer-milled wood strands that interlock to form a stable mulch layer that stays in place—even on slopes where chunkier mulches might slide or scatter.
Arbor Mulch offers solid weed suppression, cools the soil during hot weather, and is a budget-friendly option for wide coverage. Spread it 2 to 4 inches thick for best results.