The Effects of Flooding On Your Landscaping and Turfgrass

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Umbrella in a flood and effects on your landscape

If you are into growing things outside, you are almost always happy when it rains. Rain makes things grow, that is a fact. If you grow things outdoors, you know that drought is always a possibility, and that it is never an easy condition to overcome. Unfortunately, there are times when extremes can occur on both sides. If you live on the west coast, you are dealing with incredible drought conditions. For those that live on the eastern seaboard, you would welcome some dry weather after Hurricane Joaquin dumped close to 40 inches of rain within two days in the devastating “1,000 year” rain event.

How Well Do Trees and Shrubs Tolerate Flooding?

What does all that rain mean to the lawns and landscapes in these flooded areas? For the most part, unless the water sits there for more than a week, most trees, shrubs and turf should be fine. As long as the roots can continue to get oxygen, the plants will survive, and the effects of flooding on your landscape will be minimal. Some trees and shrubs can survive several months with their roots covered in water. Then there are others that cannot tolerate flooded conditions for even a short period of time. This is especially true of newly planted trees and shrubs.

Will My Lawn Be Okay after a Flood?

What about turfgrasses? Most grasses can tolerate being submerged for more than a month without permanent damage. Bluegrass and Bermudagrass can last even longer – about 55 days, without permanent damage. The biggest problem with flooding is from the movement of soil and debris over the turfgrass. In many cases, turf growing on a sloped area has a greater chance of being washed away, especially if the soil is very sandy. Turf growing in a lower area has a greater chance of being covered with soil and silt from surrounding areas.

What Do I Do After the Rain Stops?

There is not much you can do until the water recedes and you can assess the damage and amount of clean up that will be required. You may have to wait several days for the soil to firm up before starting any major clean up. Repeatedly walking across water-logged turf or driving heavy equipment across it will lead to compaction. Once the lawn dries out enough to walk across it, remove any rubbish that may have been left behind. If there are large silt or soil piles left behind, do your best to remove them using a flat-bladed shovel. If there is not much soil, you can rake the soil/silt across your lawn. Leaving too much soil/silt on the lawn could lead to future infiltration or drainage problems. Having the lawn core aerated will help it dry out and lead to an increase in rooting. If sections of the lawn have disappeared due to the flooding, additional soil may have to be added and the area resodded, especially if your lawn has warm-season grasses in it. Cool-season grasses can be re-seeded, but if it is a large area, sodding may be your best bet. Cleaning up after a flood is hard work and it can be heart-breaking, especially if it was more than your lawn and landscape that flooded. Replacing plants and turf is always easier than replacing a home and personal belongings. It may take some time to get everything back in place and clean, but it may also be an opportunity to make those changes to your landscape that you always wanted to do. Have you had success helping your lawn and landscape recover after a flood? Are you looking for more tips on dealing with heavy rains, and the effects they’ve had on your grass? Let us know in the comments. And if you need help doing the work, get in touch with your local Spring-Green owner.