Mulches are soil-protective materials that discourage weeds, maintain soil temperature and moisture, and prevent soil erosion in wet or windy weather. Organic mulches are those composed of biodegradable materials that were once alive. Cypress wood and bark are common organic mulches. Organic mulches eventually break down, adding humus and nutrients to the soil, says Virginia Cooperative Extension specialist Diane Relf. Using cypress mulch on flowers, however, has both advantages and disadvantages.
Cypress mulch is available as shredded bark, wood chunks or a combination of both. Its warm, pink color lasts for a year before fading to pinkish gray, advises University of Florida Cooperative Extension professor Mary L. Duryea. Cypress mulch is harvested from wild cypresses from Louisiana and Florida's cypress wetlands. These harvests may lessen the wetland's effectiveness as hurricane and flood barriers and deprive wildlife of habitat.
Cypress mulch harvested from old growth trees has the same insect and rot-resistance of the heartwood from which it comes. That resistance, however, is non-existent in young trees, reports the Lake Pontchartrain Basin Research Program. Because so few old-growth trees remain, commercially available cypress mulch usually comes from young trees. It's no more durable than other wood mulches.
Cypress Mulch and Water
Cypress mulch both repels and retains water. Dry mulch--especially on slopes--is highly water-repellent. Until completely saturated, cypress mulch holds onto water. It may decrease the water available to your flowers' roots. When saturated, however, the mulch prevents soil water from evaporating. Many gardeners know all too well the experience of having their carefully laid mulch wash away in the first heavy rain, leaving their flowers unprotected. Cypress mulch is no exception.
A major benefit of using organic mulch for your flowers is that, as it degrades into the soil, it provides additional nutrients. Cypress mulch from old growth trees, however, is resistant to decay. While it looks good in your flower beds longer than other organic mulches, it will not improve your soil as quickly as they do. Flowers in infertile soil may need additional fertilizer if you use cypress mulch.
Applying and Maintaining Cypress Mulch
A layer of cypress mulch heavy enough to settle into a 2- to 3-inch layer is adequate for a flower bed. The mulch should cover the entire bed. Pulling it back from the stems of individual flowering plants prevents stem-rot moisture from building up around them. Replacing decayed cypress mulch on an annual to semi-annual basis replenishes it without a complete reapplication. Restore color to old mulch by turning the faded layer under with a rake and bringing fresh mulch to the surface. Spray mulch dyes are also available, notes University of Florida Extension associate professor Robert J. Black and colleagues.