When shopping for organic mulch, you will most likely come across cypress mulch. Home improvement stores and garden centers sell either 100% cypress mulch, or a cypress mulch blend that also contains other types of woods.
Cypress mulch is often cheaper than hardwood mulch. However, cypress mulch is not the most environmentally and sustainable mulch. Consider the pros and cons of using cypress mulch in your garden before you make a decision.
What Is Cypress Mulch?
Cypress mulch is made from the shredded wood of cypress trees, either bald cypress (Taxodium distichum) or pond cypress (Taxodium distichum var. nutans). Both cypress species are deciduous conifers and native to North America.
Originally cypress mulch, which comes mainly from Florida and Louisiana, was a by-product of lumbering. The increasing demand for cypress mulch however has made the felling of cypress trees solely for mulch an industry of its own.
The Benefits of Cypress Mulch in Gardens
Cypress mulch shares the other benefits of wood mulch. It prevents weeds from growing because weed seeds need light to germinate, and mulch keeps them in the dark. It prevents the moisture in the soil from evaporating and drying out quickly, which cuts down on the amount of watering. Mulch also keeps the soil cool. As the mulch decomposes, it adds nutrients to the soil. Cypress mulch can help control insects such as termites, cockroaches, and some species of ants because the wood—provided that it comes from old, mature trees—contains oils and chemicals such as thujone that act as insect-repellants.
During the winter, mulch helps prevent frost-heaving—the lifting of the soil due to the pressure from cycle of freezing temperatures and soil defrosting. And, last but not least, cypress mulch gives yards a neat, manicured look.
Cypress much has an additional advantage over other wood mulches such as pine bark or cedar bark mulch or shredded hardwood mulch: due to its dense fibrous texture and weight, plus the way it is shredded, the pieces stick together and don’t dislodge in heavy rain, that's why it is often sold as “no-float mulch."
Can Cypress Mulch Harm Your Plants?
The properties of cypress mulch that prevent it from floating can also have negative effects in your garden. Because it is so fibrous and absorbs and holds so much water on its own, it can prevent water from reaching the soil and getting through to the roots of your plants. Cypress mulch that has baked in the hot sun, can become so dry that it will repel water and not absorb it, with the result that during a heavy downpour, water just runs off elsewhere instead of seeping through the mulch into the soil.
Why Cypress Mulch Is Not Environmentally Friendly
Cypress lumbering has decimated the tree’s populations in Florida, Louisiana, and other southern US states, leaving forests bare and prone to be taken over by invasive plants. Excessive clearing has destroyed wetlands, and with them the ecosystems and wildlife. If cypress trees are replanted at all—which they often aren’t as the land is planted with pines for future logging—it takes decades for the cypress populations to regrow.
Numerous environmental advocacy groups and universities in states with once significant cypress populations such as the University of Florida in its Florida-Friendly Landscape Care and the Louisiana State University Agricultural Center do not recommend the use of cypress mulch.
If the insect-repellent properties of cypress mulch appeal to you, keep in mind only mature trees possess them. It is highly unlikely that the cypress mulch you buy is from old trees because the natural cypress forests have been depleted, and if younger trees that have been planted in their place, they do not have those properties.
So while cypress mulch may be widely available, ask yourself if as an environmentally-minded gardener you still want to use it, especially since there are several good and much more sustainable mulch alternatives.
Alternatives to Cypress Mulch
There are plenty of other sustainable alternatives to cypress mulch. For a long-lasting much, choose a tree-based mulch such as pine bark, mixed hardwood mulch or eucalyptus mulch. Just like cypress mulch, it comes from trees in South and Central Florida but eucalyptus is grown specifically for mulch, and the trees grow much quicker than cypresses. The best kind of mulch for your for your garden or yard will depend on a variety of factors, including the needs of your green space, your visual preferences, and how much work you want to have to put in to maintaining it.