Go with the Flow

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In my role as a Master Gardener, one of my volunteer responsibilities is to answer landscape and gardening questions from Atlanta-area residents. Questions such as, Whats eating my peppers and tomatoes? and, Why wont my hydrangea bloom? are fairly easy to answer. Recommending that they spray insecticidal soap or horticultural oil spray for the edible plants and timely pruning and proper fertilization for the flowering shrubs provides a quick and easy fix for these landscape problems.

Before last summer, the No. 1 question asked was how to maintain a viable garden when little water was available. After years of troubleshooting drought-related plant problems, what a novelty it was, last summer, to answer questions regarding too much water. What I quickly discovered, though, was that many new homeowners, having purchased their houses within the last five years, were saddled with serious landscape matters.

After buying their home four years ago, one Kennesaw couple researched, designed and installed a native-wildlife habitat. They were thrilled with the results: a wonderful variety of beautiful, low-maintenance plants with a vast array of birds and animals visiting regularly. Much time and money had been spent in their pursuit of a perfect wildlife habitat, and it was an ideal landscape. Then came the spring and summer of 2003. A record amount of rain fell, and a seemingly gentle slope served as the channel to a wide pool of standing water that took weeks to drain, causing the demise of a many expensive plantsnot to mention displacing the wildlife.

Obviously, water can be a considerable problem in the landscape. Drainage and erosion problems go hand in handand the best time to avert this trouble is before the first planting hole is dug and the first pallet of sod is put down.

While it is impossible to predict every potential problem, there are indicators that can help homeowners identify current or possible problems.

Avoid Drainage and erosion problems by making sure water flows away from your home. Retaining walls and selective landscaping can help control the effects of water flow.

SURVEY THE SITUATION
The first place to look is the survey or plat of your property. The Kennesaw couple knew a piece of their property was located in a designated flood plain, but didnt really pay attention to that fact, since their house would not be affected by floodwater. Based on their experiences with the weather, they didnt anticipate that the flood plain would affect their landscape plans. It was a costly mistake; if an area is a designated flood plain, at some point it will be inundated with water.

Another thing to keep in mind if a designated flood plain is on your property is that the soil in these areas is generally hydric, or capable of holding water much more readily than most soils. If this is the case, your choice of landscape plants will be limited to those that can survive in swampy conditions.

The survey also will show drainage easements (labeled d.e. on the map). Drainage easements are the paths water will take across land during a downpour. Erosion frequently is a problem along these easements, so it is important to be aware of their location when planning for fences, structures or planting beds.

What about that creek that meanders gently through the back yard? While a creek is a seemingly desirable feature in the landscape, be careful when planning a landscape around it. It may flood during heavy rainstorms, resulting in unstable soil conditions and stream-bank erosion problems. Retain stream-bank vegetation to help maintain the water quality and diminish the likelihood of future erosion, and, if necessary, replace vegetation to discourage future erosion.

Examine your property carefully next time it rains. Watch for runoff from the roof, the gutters and hardscape areas (driveways, patios, sidewalks), as well as from your neighbors yards. Does the water follow a neat pathway from the gutter downspout, along the driveway to the street and into the storm sewer? Does a sudden downpour create a reservoir in your front yard that takes days to drain away? Make note of your observations, so you can make modifications to your property before you begin landscaping.

CONTROL DRAINAGE
If youve got drainage and erosion problems, what can be done to improve the situation? First of all, remember the laws of gravity, and that water will flow to the lowest point available. With that said, you must ensure that water flows away from your house, and does not pool or puddle around the foundation. Make sure the ground slopes away from the house and the foundations, so surface water runs away from the building. Take a look at the earth around your house; if it doesnt appear to be sloping at least slightly away, fix it.

Make sure gutters are kept clean and downspouts pipe water to a driveway, drainage easement or practical lower spot in the yard. This may require extra fittings or pipes be added to your gutter system. It is well worth the money, so that the foundation and surrounding areas will not be compromised.

The solution used to correct drainage problems depends largely on the extent of the problem. If it is not too severe, such as a small amount of excess surface water on the yard, improving soil structure alone may solve the problem. In the Atlanta area, the heavy clay soil holds water and does not allow good drainage. Tilling the soil and adding organic material can be helpful, additionally providing better environment for plant growth. For low spots in the lawn, leveling the area with additional topsoil may be the answer.

In addition to strategic construction, rain gardens, made up olants that tolerate “wet feet”, are a low-maintenance way to use rainwater to benefit the landscape.

PLANT A RAIN GARDEN
Rain gardens are a low-maintenance addition to the landscape, intended to capture rainwater. Planted with vegetation that tolerates wet feet, they are located in areas that absorb runoff and hold it for a short period of time. Rain gardens reduce flooding risks significantly, allowing positive utilization of excess rainfall.

You may have a boggy area in your yard, due to underground springs or a low water table. If this is the case, surrender to it and plant shrubs, trees and perennials that love wet feet. If you have more significant drainage dilemmas, soil improvement or leveling may not be enough. A diversion, such as a swale, could be constructed to channel the water to a more desirable spot, and prevent pooling in the yard. A popular solution is to create a dry creek bed, providing an interesting focal point to the landscape during dry weather, and serving a useful purpose when the rainy season arrives. Both swales and dry creek beds also help significantly with erosion.

GO BENEATH THE SURFACE
If neither of these options is feasible in your landscape, subsurface drainage might be the answer. Underground collection pipes, catch basins and channel drains can be installed to remove large amounts of potentially damaging water.

French drains are another alternative, particularly around the foundation, in raised beds or planting areas. These drains collect water and allow it to slowly seep back into the ground. In some situations, drain fields can be dug and filled with crushed rock to enable water to seep into the earth.

While handy homeowners can install simple drainage systems, larger or more complicated jobs might be better suited to a landscape professional that is an expert in grading and drainage work.

Turf, mulch and other groundcover are exceleent remedies for eroding soil, particularly on a gradual slope.

ERASE EROSION
What about erosion caused by drainage problems? Planting vegetation often is the best solution, since the plants roots will help to hold soil in place. Turf and groundcover are an excellent remedy for eroding soil, particularly on a gradual slope. For more steeply graded areas, terraces may be built to slow the water flow. Terraces also can provide wonderful planting areas for the landscape. If there is a great deal of erosion present, it may be necessary for topsoil to be brought in to enhance the existing earth.

Professionals who specialize in erosion and soil issues also have numerous products that can help to correct serious problems.

AVIOD THAT SINKING FEELING
Another landscape problem that has become more common in metro Atlanta is the occurrence of sinkholes. Common in Florida due to developments built over underground limestone caves, sinkholes holes seemingly appear overnight, causing distress to homeowners.

Most sinkholes occur where debris such as trash, stumps, tree branches and other building materials were buried during construction. Over a few years, the debris decays, leaving an empty cavity in the ground. Hidden under a layer of soil, the hole finally caves in, resulting in a sunken area in the landscape. If you encounter a sinkhole in your yard, inspect it by enlarging the surface so that you can see inside with a flashlight. If you see building materials or decaying branches, it is a construction sinkhole. Poke into the hole with a stick, and determine if it is solid at the bottom and the sides. If so, you probably can fill the hole yourself, adding layers of soil, a foot at a time, and packing it firmly until filled. You can then safely plant turf or small plants in the area. If there is standing water or a pipe in the cavity, it may be a broken sewer line. If so, contact the county or city water department for guidance.

PLAN YOUR PROJECT
Just as in any home-improvement project, research and proper planning before you start the task will help ensure a successful final outcome. Take care of problems in the landscape before you plant, and in the longrun youll save time, money and lots of headaches.