Types of Lumber Used for Flowerbeds

Redwood

• The oldest portion of a redwood tree --- called "heart" wood --- contains enough tannic acid to repel pests and deter rot. The redwood tree's heartwood also carries the tree's namesake color: a deep, brownish-red. The outer, active portion of the tree, called sapwood, is primarily white and doesn't contain enough tannic acid or color to warrant a higher price tag. However, redwood heartwood is a traditional, attractive and durable choice for flowerbeds and planters of all types.

Cedar

• Cedar generally costs less than redwood, yet contains similar rot- and pest-resistant compounds. Unlike the striking red color of redwood, cedar typically has a subdued, golden-brown hue. Additionally, without the application of surface coatings, such as waterproofing compound, cedar lumber weathers to a dull gray. However, many gardeners appreciate the worn look of weathered cedar and intentionally leave cedar flowerbeds untreated.

Pressure-Treated

• Although pressure-treating refers to a specific manufacturing process, builders use the term "pressure-treated" to refer to all types of chemically treated wood products. The most familiar type of pressure-treated wood is the "green board" commonly used as a foundation sill plate. Although green board is literally green in color, alternative chemical treatments result in reddish hues or clear coats. Chemically treated lumber is suitable for direct contact with moist soil, such as flowerbed construction. Because manufacturers use inexpensive lumber to produce treated wood products, treated lumber costs less than naturally rot-resistant lumber, such as redwood and cedar.

Railroad Ties

• Although technically a type of treated lumber, the unique appearance and widespread popularity of railroad ties places them in a category of their own. Railroad ties are large beams that are typically coated with creosote and buried in the ground below metal railroad tracks. Railroad companies continually replace railroad ties. Despite its weathered appearance, used railroad ties will last for decades, even when in direct contact with soil. Typically 6 inches by 8 inches or larger, railroad ties are heavy and unwieldy. However, their chunky, loglike appearance and rich brown color has widespread appeal for all types of landscaping applications, including steps, flowerbeds, borders and planters.

Safe Handling of Creosote and Pressure-Treated Products

• Despite their widespread use and popularity, working with creosote and pressure-treated lumber requires attention to several precautions. To avoid prolonged contact with potentially harmful wood preservatives, builders must wear protective gear when working with creosote and pressure-treated products. Protective gear includes dust masks and goggles during the sawing or machining of preserved wood products and full skin protection, such as long sleeves and gloves, during the prolonged handling of preserved wood products. Manufacturers suggest that workers thoroughly wash hands and skin following bare-skin contact with the products and that workers wash exposed clothing separate from regular laundry. Burning preserved wood products releases harmful chemicals into the atmosphere. Never burn preserved wood products; dispose of the products at solid-waste landfills.