Flood Recovery

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Photo of breached Levee in 2019 Flooding along the Missouri River, Photo by John Wilson, Nebraska Extension Educator

Many parts of Nebraska have faced flooding issues recently that have done a great deal of damage to homes and properties. Flooding has also caused damage to our landscapes and garden spaces.

Trees in the floods

Floods can do a lot of damage to our trees, depending on the length of time the trees were under water. According to the University of Wisconsin Extension, most plants can tolerate a few days of flooding during the growing season. Now that flood waters have or are receding take time to look at your tree and assess the damage.

When assessing the damage to your tree, make sure the roots remain at the same level in the soil and remove debris from around the tree roots. Hire an arborist to remove broken branches and check the stability of any leaning tree. If the tree is now leaning toward a building or other damaging location, have the tree removed. Do not fertilize your trees for at least a year to avoid further damage or disruption to re-establishing roots.

Garden space in the floods

Vegetable Gardens would be a concern due to food safety reasons. Floodwaters are not clean and they can carry bacteria and other harmful debris and pollutants with them as they move across the land. Fortunately, the floods came through before our gardens were planted, but there is still a concern with the soils and what crops we will plant. Spring garden crops and crops with edible parts coming into contact with previously flooded soils would be the most concerning.

According to John Porter, Urban Ag Program Coordinator for Nebraska Extension:

The recommendation depends on whether or not the crop comes in contact with the soil.  For crops that do not have direct contact with the soil, such as tomatoes, peppers, beans, etc. the waiting period between flooding and harvest should be at least 90 days. For crops that do have direct contact with the soil, such as lettuce and leafy greens, squash/pumpkins, and root crops such as potatoes and carrots the waiting period should be at least 120 days.  If the crops that don’t typically make contact with the soil are allowed to make contact, like tomatoes that aren’t staked, the 120 day recommendation should be followed.

Food safety concerns wouldn’t be present to gardens that were not affected by the floods. We can still plant our gardens into the soil during the 90 or 120 day waiting period, but any mature harvest should be discarded until after that waiting period for food safety. This means that we should opt out of spring gardening in areas where the floods impacted our vegetable garden spaces. Most of our summer crops would be fine, but you may want to use a trellis for cucumbers and use container gardening for things like zucchini to be on the safe side.

Turf in the floods

Lawns are resilient in flooded areas. It is best to stay off of wet lawns to avoid compacting the soil. Wait until it has dried out before mowing, driving equipment over, walking excessively over, and cleaning up the debris that may be on the lawn. Turfgrass can survive 4-6 days submerged, according to Missouri Extension. Most of our localized flooding receded quickly, so the lawn should survive. Also, because the flooding happened during the dormant period for the turf, the injury will be less than if it occurred during the warmer growing season. In areas that are still under water, when the floods do recede soil work, clean-up, and overseeding will be necessary. We may also see an increase in lawn diseases this summer due to the high amounts of rain and floodwater that affected them this spring. View this Turf iNfo on Turf Recovery after Historic Flooding for more information.

For more Flood Resources, visit: flood.unl.edu

 

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Landscaping Around a Tree

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This photo shows a good example of landscaping under a tree. Notice the wide, thin mulch rings.

The winter is a great time to start thinking about spring gardens. One of the gardens you might think about for improvement or development is around trees. There are things you can do around trees to help improve the overall look of your landscape, but be careful, some things may be harmful.

Exposed Tree Roots

Exposed tree roots are often a problem in landscapes. Some trees will pop their roots up and out of the ground which makes it difficult to mow around and can be a trip hazard. Unfortunately, there is not a good fix for this problem. If you were to cut the root to remove it from above the ground, you would severely injure the tree and possibly kill it, depending on the size of the root. Adding more soil around the root to try to cover it up is also a bad idea. Adding more soil to the existing grade of a tree can suffocate the roots and kill the tree.

Raised Beds around Trees

One idea many people want to use around their trees is to add a raised bed around an existing tree. Adding the soil necessary to make a raised bed around a tree can kill the tree. If the tree is correctly planted into an established raised bed after the raise in soil grade is complete, that would be fine. However, adding this bed around an existing tree will severely damage the tree and could lead to tree death. Trees are slow to react to these things, so your tree may live just fine for 5-10 years, but then the damage will begin to show up as the canopy starts to thin or die.

Turf under Trees

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Thin turf under a tree, photo from John Fech, Nebraska Extension Educator

Another issue around trees that many people ask about would be thin turf growth or constantly bare soils under a tree. Turf is a sun plant and it will not grow well in shade. There are shade mixes in the market, but those are designed for light shade. Underneath a full grown, healthy tree is often too much shade for the turf to grow in.

A better option instead of thin turf for underneath the tree would be to just mulch the area. Mulch helps to keep the weeds down, retains moisture, keeps the roots cool, and keeps the lawn mower and weed trimmer back away from the tree trunk to reduce the incidence of damage from this machinery. Keep the mulch at a flat layer of 2-3 inches deep and don’t create a volcano of mulch around the tree. The mulch ring should be at least a 3 foot diameter around the tree, but it can be as wide as the dripline.

You can mimic mother nature and provide a nice growing environment for your tree by utilizing mulch and shade plants under the tree. You can plant shade plants into the area around your tree as long as you don’t add soil to put them in. In nature, trees grow great on their own with little input from humans. A big part of that is the growing conditions they are placed in. Trees in nature grow with leaf litter and smaller plants growing all around them. The leaf litter acts as a mulch and the shade plants thrive in the shade of the large trees.