“Mulch” is a blanket term meaning a layer of organic material applied to planting beds. I think of it as a term describing the action (“to mulch”) rather than a specific product. “Mulch types” are varied and each can be beneficial.
There are three main types:
Mulch Type Comparison
Choose the right mulch for your landscape needs
| Mulch Type | Pros | Cons |
|---|---|---|
| Fresh Woodchips (Arborchips) |
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| Partially-Composted Woodchips (bagged/bulk) |
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| Compost (bagged/bulk) |
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- Mulch types to avoid: actual tree bark, cedar chips, and dyed woodchips. Bark and cedar chips do not decompose well and can have properties that inhibit plant growth. Dyed woodchips leach harmful chemicals.
Why to Mulch?
When applied properly, mulch acts as a safety-blanket for plant root zones and helps promote long-term resilience and vigor. Applying mulch is a cultural practice much needed in most landscapes.
The primary benefits of applying a mulch product:
- Soil temperature regulation throughout the year (cooler in the Summer, warmer in the Winter)
- Increased soil-moisture retention (less frequent watering through Summer)
- Improved soil microbiome and soil quality (decomposition via microbes aerates and nourishes underlying soil)
- Short-term “weed” prevention (sheet-mulching increases this benefit greatly)
How to Mulch?
Applying mulch is fairly straight forward but can seem tricky to the inexperienced. Properly applying mulch is crucial to obtaining the benefits and avoiding harm to trees.
Key points to properly mulching:
- Select the mulch type that best fits your goals, aesthetics, and abilities
- Target the wider root zone of each plant/tree (from trunk to edge of canopy)
- Soil moisture should be high prior to mulch application (manually water in Summer)
- Do not pile against the trunk (trunk flare should be visible)
- Mulch product should be 2-3” thick
Sheet-Mulching:
- Cut grass/etc as low as possible (no need to dig)
- Soil should be well-watered
- Apply overlapping layers of cardboard to cover target zone (remove tape/labels beforehand)
- Wet the cardboard thoroughly
- Apply 3-6” layer of mulch product (thicker layer to weigh down the cardboard)
*Pro-tip – establish an edge by digging a 4-6” wide trench around perimeter of target zone. Cardboard should end just inside of trench and mulch at outside-edge of trench. This will keep a sharp line and prevent the cardboard from popping up.
