How to Garden by Treated Fence Posts

What Not to Plant

• 1

  Avoid edible plants such as vegetables or berries. As the National Organic Standards Board points out, toxic chemicals from treated lumber can leach into soil and be absorbed by plants. Reduce the chance of chemical contamination in edibles by not planting them next to treated fence posts.

• 2

  Resist plants with high picking appeal if there are children in your family. Spring bulbs, which are so appealing after a dull winter, can draw children close to and perhaps onto treated wood. If finding the first snowdrops and picking grape hyacinths is exciting for your family, plant the bulbs at least 3 feet from the fence posts so the flowers and the soil they grow in can be safely touched by youngsters.

• 3

  Find another location for low plants children can step over to reach the treated lumber. Pansies, candytuft, dwarf snapdragons, lobelia and impatiens, for example, are easy to hop over when chasing a ball. With children, pets and treated outdoor wood, the game you need to play is keep-away.

• 4

  Writing in "Fine Gardening," Ruth Lively makes the point that the issue in landscaping around treated fence posts is not a matter of preventing a child or adult from biting into a single arsenic-loaded string bean. Rather, since some arsenates, borates and/or copper salts tend to leach into and stay in close-by soil, landscaping should be directed toward avoiding chronic small encounters with toxic soil that can, in time, lead to cumulative poisoning of children, animals and even adult gardeners. She further points out that one reason treated lumber was EPA-approved for general garden and landscape use is that CCA or borated lumber does not affect the growth of plants as did earlier lumber preservatives such as creosote. Thus, flowers, shrubs, and vines will thrive; soil accumulations of chemicals are not enough to hamper their growth.

• 5

  Stay current on the effects of new preservative compounds used since the withdrawal of CCA wood from the residential construction market in 2004. The University of California cites remaining concerns about disposal of CCA wood and appears not to have final evidence of the harmlessness of wood treated with alternative alkaline or amine copper quat (ACQ) or copper azole. The University of California's studies note that the EPA still considers CCA wood suitable for many landscaping uses, differing with parents concerned about the chemicals their children may absorb from soil and CCA play equipment. For the present, families may wish to take a look-don't-touch stance on all forms of treated wood until further results develop.

What to Plant

• 6

  Use the natural defenses employed by plants to keep humans away. Climbing or rambling roses make a fine show on a treated fence, while thorns keep admirers at a distance. Other sun-loving climbers can enhance your fence; consider trumpet vine or wisteria as ornamentation that will last as long as your fence.

• 7

  Take advantage of well-known shade lovers that may demand too much space in the rest of your yard. Clematis, honeysuckle and climbing hydrangea will fill as much room as you give them, managing to be both dense and decorative at the same time. As with sun-loving climbers, they make it hard, if not impossible, to get close to treated posts and have the further keep-away feature of attracting beneficial insects.

• 8

  Enhance a split-rail treated fence with a hedge planted on the inside edge. This strategy gives your yard a more formal look and increases privacy at the same time.

• 9

  Build a height-graded perennial border against your fence, and then allocate space in front of these woody shrubs for annuals. The mixture of colors and the variety of different, overlapping bloom periods lets both you and passersby admire a barrier-turned-border. This is a particularly beautiful way to protect family members from the toxins in treated wood posts.

• 10

  Scout out long-lived untreated fence posts to replace treated ones as weather and soil take their toll. Osage orange, black locust and cedar have reputations for durability. Woods may vary in your area, but increasing numbers of lumberyards are offering durable untreated lumber as well as treated items.