Tips for your yard and garden after heavy rains or flooding

Here are some tips for your lawn and garden after heavy rains or flooding from Louisiana State University Ag Center and other sources:.

Hurricanes and heavy rains can create excessively wet soil. If combined with high temperatures it can create stressful, and potentially deadly, conditions for bedding plants, perennials, vegetables, shrubs and even trees. 

When the soil is saturated with water, pore spaces in the soil that normally hold air are filled with water. Since the roots of plants get the oxygen they need from the air in those spaces, the roots can literally drown when soils stay waterlogged for an extended period. A sick root system leads to a sick plant. 

Wet conditions also encourage fungus organisms in the soil to attack the roots or crown of a plant and cause rot. The crown is the area where the stem of a plant enters the soil. These disease organisms can cause dieback or severe damage or even kill plants. Once infection occurs, little can be done to help a plant. Plants with succulent stems, those that like lower temperatures and those that prefer drier, well-drained soils are particularly susceptible.

Here are some tips for gardens affected by heavy rains:

1) Under saturated conditions, mulch should be pulled back from around plants or removed from beds entirely. This will allow evaporation to help the soil dry faster.

2) You can help plants that were affected by wet soils or root rot by aerating the soil in the root zone. Using a garden fork, drive the tines straight down into the soil about 8 inches and pull straight out in numerous places around the shrubs. Do not dig with the fork, but make as many holes as seems practical. This technique provides air to the roots and encourages the soil to dry faster. A metal rod or wooden dowel could also be used to make the holes.

3) Pests such as snails and slugs, which chew holes in leaves and flowers of many plants, thrive and reproduce rapidly during rainy weather. Try not to let their populations get out of control. If you have toads in your garden, that's great because they feed on slugs. You can place a bowl up to its rim in the ground and fill it half full of beer to attract and drown many snails and slugs or remove them by hand and dispose of them humanely.

4) Heavy rains over an extended period will leach available nutrients from the soil in the landscape. This is especially true of nitrogen and potassium but not so much for phosphorous. Give your plants a chance to recover from the saturated soils, and fertilize if needed if they do not improve. Do not fertilize hardy trees, shrubs and lawns after August, even after heavy rains. Late fertilization can make them less winter hardy. Do consider fertilizing bedding plants and vegetable gardens, if needed. Dried blood meal can add nitrogen to soil while rock potash can supply potassium.

5) Do not consume any vegetables that may have been touched by floodwater. There may be contaminants in the water. In general, fruits and vegetables which were immature at the time of flooding should be safe to eat by the time they are ready to harvest.

6) Some fruits and vegetables are more susceptible than others to bacterial contamination.

1. Leafy vegetables such as lettuce, cabbage, mustard, kale, collards, spinach, swiss chard, celery, and fleshy vegetables and berry fruits such as tomatoes, summer squash, strawberries and peppers are highly susceptible to bacterial contamination. Silt and other contaminants may be imbedded in the leaves, petioles, stems or other natural openings of fleshy structures and can be difficult to remove.
2. Root, bulb and tuber crops such as beets, carrots, radishes, turnips, onions and potatoes are less susceptible to bacterial contamination. Disinfect these vegetables, peel and cook them thoroughly before eating.
3. Produce with a protected fruit or impervious outer skin such as peas, melons, eggplant, sweet corn or winter squash should be washed and disinfected before the outer shell, skin or husk is removed. Then shell, peel or husk the produce and cook it if possible.

7) For additional safety, disinfect produce and cook it before eating.

8) Gardeners should take extra precautions to use good personal-hygiene when working in gardens that may have been flooded. Wash hands before and after gardening. Leave garden shoes at the door, and change clothing after working in a flooded garden. Avoid direct contact with flood waters, including the soil, as much as possible. Young children can be at a high risk for flood related contaminants. If a garden plot has been flooded, consider either not having young children in the garden with you or take precautions to utilize good personal hygienic practices.

9) Newly planted seeds and transplants may not survive even short-term flooding, and seeds may have washed away. Resist the urge to replant immediately; give the soil a chance to dry out first. Working wet soil will have long-lasting effects of soil compaction.

10) Many snakes are left homeless after a flood. They may seek food and shelter in debris caused by the flood or yard cleanup. Watch where you put your hands and feet when removing or cleaning debris. More information about local snakes.

11) Heavy rains can result in excessive breeding of mosquitoes, resulting in the possibility of disease being carried by the insects. Remove excess water from birdbaths, flowerpots, tires, buckets and other containers to minimize the breeding of mosquitoes.

12) Bees, wasps, and hornets may have had their nests disturbed by excessive wind and rain. The insects can become very aggressive. Before beginning clean up, survey the site to see if bees, wasps, or hornets are hovering in the area. Take necessary precautions to avoid these insects.

In addition to the obvious damage to plants, there are more long-term effects to soils, which have been flooded for extended periods. Soil microorganisms that require oxygen may be killed and those that survive without oxygen take over, which in turn affects availability of nutrients for plant use. The soil structure itself may be physically harmed due to compaction of soil particles.

It will be difficult to know the full effect of the heavy rains in the area until things begin to dry out. And then, of course, a lot will depend on what future stresses the weather may bring to our landscapes.

For more information contact your local Extension office:  

Cooperative Extension Services

• Virginia Cooperative Extension
• Home and Garden Information Center - Maryland Cooperative Extension
• Cooperative Extension Service – Washington, DC

or these sources, which I used in this articles:

Sources: Flooded Lawns and Gardens, LSU Ag Center

Flooded Gardens, (pdf file) South Dakota Cooperative Extension

After the Flood: Garden and Landscape Plants, Purdue Extension

Preventing Disease and Illness in a Flood – Fairfax County

Lessons from a hurricane, part deux - what goes in the ground, comes around

And then the sky broke up
And then the rain came down
And it washed away everything on the ground
Wash it away, wash it away, wash it away.
Lyrics from Ghost Train, by Marc Cohn

 
I remember watching the news after a hurricane a few years ago, and there were children on inner tubes playing in the water from the flooding caused by the storm. All I could think about were the chemicals and pollutants that were probably in that water.

While hurricane  Irene was making her way up the east coast, I watched several online discussions on local gardening message boards about gardeners using roundup and other poisonous weed control products.

Sure, I can understand the children not realizing how many chemicals and how much dog poo and probably septic tank seepage is  in that stormwater. But I found it a little troubling that the adult gardeners didn't seem to realize the connection between garden chemicals and the torrential rains that were expected from the hurricane.

An article in the Green column of the New York Times this week talked about the pollutants from hurricane Irene:

Beyond flooding and destruction, Hurricane Irene is likely to have caused less visible environmental damage by dumping sewage, pesticides and other contaminants into waterways along the East Coast, federal officials said.

Officials are just beginning to assess the condition of seven rivers, including the Hudson River in New York. The United States Geological Survey said it sent out crews beginning on Sunday to follow the path of the hurricane between Washington D.C. and Massachusetts and test for pesticides, bacteria and nutrients flushed into rivers by heavy rains.

“What typically happens is that you get a significant amount of rainfall that leads to a significant amount of runoff,” said Charles Crawford, sampling coordinator for the agency. 

That runoff, he said, carries pesticides from farmland, gardens and lawns like those used for termites around the foundation of homes. The agency is also on the lookout for higher levels of bacteria and nutrients from sewer discharges. 

Excessive amounts of nutrients like nitrogen and phosphorus, Mr. Crawford said, could cause algae blooms that can threaten aquatic life and fisheries.

In typical weather conditions, chemicals used in a landscape might have time to soak into the ground and dissipate, not allowing strong concentrations to find their way into the waterways. But during periods of heavy flooding, the products that are in the ground around your home can seep up and wash away. In areas where the flooding is severe, any chemicals that are stored on the floor of sheds or garages might  also find their way into local stormwater drains.

Water quality scientist Beth McGee, of the Chesapeake Bay Foundation, voiced her concern about this problem as the storm approached. McGee said that much of the flooding that occurs during storms is a result of runoff from streets, lawns, farms and other areas, as well as tides that bring water up the bay. Preserving wetlands, creating buffer areas and landscaping areas to allow stormwater to trickle into the ground instead of running off into nearby waterways can help reduce flooding.

So in my opinion, if you want to "round up" anything, you should round up the chemicals that you have been using in your landscape and dispose of them properly:

Household Hazardous Waste Disposal, DC
Household Hazardous Waste, Montgomery County
Household Hazardous Waste, Frederick County
Household Hazardous Waste, Fairfax County
Household Hazardous Waste, Loudon County
Household HazMat Program, Arlington
STOP Throwing Out Pollutants, Prince William County

After the Storm - Lessons Learned about People and Trees

Shhhh. Do you hear that? It is the collective sigh of relief in the wake of hurricane Irene. Or haven't you let out your sigh of relief yet? I think it’s okay now. Go ahead and breathe.

And now, comes the clean up. And the lessons learned.

One of the first things that I always seem to notice after something like this is what I learn about people. I think that any sort of emergency or disaster either brings out the kindness or the cruelness of people. There are those who reach out to their friends and neighbors, checking in, seeing if they need anything. And there are those who shove ahead of others in the crowded department store lines or loot the homes of people who evacuated their homes. With all of the stress of hurricane preparations and recovery, it's a little disheartening to learn about the negative side of people. So just ignore it. Move on.

The other lessons, of course, are the ones that are learned from Mother Nature. As of this writing, there are at least 19 deaths attributed to hurricane Irene. At least 11 of those deaths were caused by fallen branches or trees.

Millions of people were without electricity during the storms. Again, many of the power outages were caused by fallen trees.

I am a self-professed nature nerd and tree lover, so these statistics about the cruelty of nature  bother me as much as the reality of the cruelty of people. But these thoughts are not quite as easy to ignore. I can do my best to avoid unpleasant people, but my soul would suffer if I thought I had to be fearful of trees.

Thankfully, there has been a lot of research done on hurricanes and trees, conducted  by the experts who have experienced much of it first hand, researchers at the University of Florida IFAS Extension.  Since 1992, they have been studying the kinds of trees that were more apt to break or topple over during hurricanes, as well as the reasons why.  True, some of what they learned was about treess that don’t grow in the northeast. But as with most things in nature (human nature and mother nature) many of the lessons that life provides are not geographically specific.

If you lost trees or lost power, or are just interested in  learning a little bit more about trees and hurricanes, the University of Florida has created an entire website devoted to Trees and Hurricanes.

For example, some of the trees that were found to be MOST wind-resistant in their studies include: American holly, inkberry and bald cypress.  Some of the trees that were the least wind-resistant were:  tulip poplar, southern red oak and water oak.

Here are a few more of the  lessons learned:

Root/Soil Issues

• Trees growing in confined soil spaces are prone to blowing over.
• Root defects such as girdling roots cause trees to blow over.
• Apparently healthy trees can blow down because supportive roots have decayed or soil becomes soft from saturation.
• Large and old trees blow over; recently planted trees blow over; well established young to medium-aged trees are less likely to blow over.
• Construction activities within about 20 feet of the trunk of existing trees can cause the tree to blow over more than a decade later.
• Trees in shallow soils are more prone to blow over than trees rooted more deeply.
• Uprooted trees can break underground utility lines such as water and sewer.
• Trees become unstable in soils saturated by lots of rain.

Cultural Issues

• Trees that are preventively pruned are less likely to fail than neglected trees.
• Trees with one dominant trunk fair better than trees with co-dominant stems.
• Trees with bark inclusions are prone to falling apart.
• Large pruning cuts create decay and cracks that can lead to breakage in storms.
• Trees in a group blow down less frequently than single trees.
• Tree trunks can be hollow without openings in the lower trunk; these are prone to failure in storms.
• Trees that have failed before are likely to fail again.
• Topped trees break.

So while you are enjoying the relative peace in the wake of the storm, think of the lessons learned. Take care of the people and the trees that you love. And don’t be reluctant to get rid of the ones that may only end up hurting you.

Source: Trees and Hurricanes