Organic mulch normally lasts 5-6 years. Though, several factors may cause you to have to replace or replenish mulch every 1-2 years.
Organic mulch decomposes over time, so it will need to be replaced eventually. A typical mulch may last about five years, but this timeframe can decrease depending on the type of mulch, weather conditions, rainfall, sun exposure, etc.
For most landscaping and planting applications you’ll have 2-3 inches of mulch in place. If rain, wind, and foot traffic removes some of that, you may need to add much to ensure proper coverage. If you have frequent heavy rains, or if you have soil and climate conditions that speed up decomposition, you may also need to add mulch periodically.
Mulch Color
Another factor is the color of the mulch. Some undyed mulches may start to turn gray after about a year. It’s still effective, just not as attractive. Many people choose to replace all, or some of the faded mulch to improve the landscaping aesthetics.
Dyed mulches may hold their color longer, but it is important to learn how the mulch was dyed. The cheaper mulches that use artificial processes to color the mulch can have some negative impacts as the dye penetrates your soil. For this reason, dyed mulches are often removed and replaced each year. Make sure you understand what you mulch is made of, and how it might impact your soil before placing it in your yard and planting beds.
Mulch Size
The size of your mulch also impacts how long it lasts. Bark mulch normally lasts longer the wood chips. Shredded mulch sometimes washes away with rain, or blows away in high winds. So, shredded mulch will need to be replaced more often than chips or nuggets.
What happens if you don’t replace old mulch?
Eventually, all mulch will decompose and no longer provide the benefits it was designed for. Organic mulches provide nutrients to your soil while retaining moisture and protecting the soil. As your mulch decomposes or is reduced in-depth, you become more likely to see more problems with soil erosion and weeds.
Many people use landscaping mulch strictly for aesthetic value. As mulch ages, it will fade and lose its color. This process could take several months or a few years, but it is inevitable for all types of mulch.
Mulch Maintenance
If you’re looking for low maintenance mulch, look for a large bark mulch that hasn’t been dyed. Cedar and Cypress bark are good choices. This will decompose more slowly than other options.
You’ll likely only need to perform minimal maintenance after a couple of years if you’re using a good natural mulch. Keep an eye on the depth and make sure you’re in the 2-3 inch range for the best results. Don’t allow the mulch to pile up around trees and plants as too much depth can reduce air circulation and harm plants and invite insect and rodent activity.
While there isn’t a single, simple answer to “How often should you replace mulch?”, it is widely accepted that it is important to maintain your mulch. Mulch should be replenished or replaced as you start to see signs of decomposition, soil erosion, and discoloration. And you’ll most likely need to remove and replace all mulch after 5-6 years.