They also can be found in a subdivision that was built on a former swamp or a lot that was not graded correctly so it doesn't slope away from the house.
All of these scenarios create unfavorable growing conditions for plants. They get "wet feet," which is a catch-all term for a list of diseases and problems associated with poor drainage. Areas with poor drainage tend to hold moisture, and this often causes the roots of a plant to rot.
If root rot affects the crown or major roots, the plant can wilt and die rapidly. If the rot affects only the small "feeder" roots, the plant may decline slowly and just look sickly and be unproductive. The damage may be present on only a part of the root system, resulting in the appearance of yellow, stunted leaves on part of the plant.
Usually, a plant situated in a poorly-drained area will turn yellow in a few months. Many folks throw out some fertilizer, thinking the plants need nitrogen, and this makes things worse. Then they compound the problem by watering too often.
Providing good soil drainage can prevent most root disorders. That means you need to slope beds and lawns so water runs away from the house. In some drastic cases, this may require re-grading, but this may be the only solution if you want to grow plants.
If there is a slope going toward your house, you may have to create a swale to carry the water away from the house.
For those of you in swampy or low areas, grading is usually not the answer. In such cases, you may need to construct drainage channels or install French drains.
Installing gutters can help in many cases if you don't have them. If you have gutters, make sure they drain properly and the downspouts drain away from the plants and don't pool water. Adding an extension pipe on downspouts can help solve problems by releasing the water farther away from the house.
You can also provide drainage by using raised beds, which is particularly good for annuals and tender perennials.
Amending planting beds with 3 to 5 inches of good topsoil or compost will help improve drainage. A general rule of thumb for applying organic matter is to add 25 percent by volume. Using less organic matter than this won't provide enough soil structure change to make a difference.
If you're planting a tree or bush, don't place soil amendments directly in the planting hole. Till or spade the amendments into the entire bed if possible. Dig single planting holes at least twice the size of the root ball.
You can check the drainage conditions before planting by filling the hole with water. If most of the water is still there an hour or two later, a drainage problem is likely. If so, take corrective measures or use only plants tolerant of poorly drained sites.
Never place a plant deeper than the top of the root ball. This is a common mistakemade when it comes to planting. Keep the plant raised up as you are putting the soil back into the hole.
Another common mistake is over-watering. Most plants need about one inch of water per week to look and perform their best, but sometimes less is needed in poorer drained areas. Most shrubs, once established, can go much longer without water. Far too many people water them every other day because they are watering their grass every other day, so the shrubs get it whether they need it or not. This leads to root problems.
Roots need oxygen and excess water forces oxygen out of the root area.
Sid Mullis is the director of the University of Georgia Extension Service Office for Richmond County. Call him at (706) 821-2349, or send e-mail to firstname.lastname@example.org.