Friday, September 1, 2023

Hurricane-scaping in Florida

Hurricane Idalia 2023

Florida's hurricane season is from June 1 to November 30. These five months are also the wet season here when we receive up to 70% of our annual rainfall. Our hot wet summers make it difficult to grow some vegetables like sweet basiltomatoes and most members of the squash family, but growing crops is not the topic for this post.

As I'm writing this, Hurricane Idalia is pummeling the west coast of Florida. Florida is subjected to more hurricane activity than other states because the 1,350 mile-long coastline, which is surrounded by warm waters. When sea surface temperatures are above 82˚F, this warm water sustains and intensifies tropical storms that may strengthen into hurricanes. This year the Atlantic Ocean temperatures reached as high as 101˚F just off the east coast of Florida. So it's not surprising that we have been struck by a Category 4 hurricane.

While there are several actions you can take in the landscape to make it more wind-tolerant, if your property suffers a direct hit of a strong hurricane, there will be significant damage wind and storm surges no matter what precautions you might have taken. This is especially true for more coastal properties. Even then, storms can do serious damage. In 2017 during Hurricane Irma, we lost 8 large trees out back in a relatively wide stretch of woods. Three were broken off at 25 feet above the ground. We suspect that there was some type of tornadic activity that took them down. Fortunately for our neighbor, they did not fall on his house. We are in North Florida 45 miles from the east coast and 130 miles from the west coast--we are definitely not coastal.

With this in mind, we'll cover four hurricane-scaping ideas to help you make your property and your community more resilient to tropical storms.

Control and sequester stormwater

Capture some of the rain with multiple rain barrels for more capacity, this increased volume will be useful during the dry season for irrigating crops and wetting compost piles.

Create a flow chain for the stormwater including rain barrels, rain gardens, ponds, and overflows to wooded areas or large bioswales.

As sustainable gardeners, we want to sequester as much rainwater on our properties as possible to improve the quality of nearby waterways and to recharge the underlying aquifers. We all live in a watershed. I've written several articles on rain barrels, rain gardens, and drywells listed under "rain" on the Green Resources webpage. If there are roadside swales at the edge of your property, these help as well.

Storing stormwater may seem like the opposite of what you'd want to do when there's an approaching tropical storm, but controlling where it goes will help protect vulnerable areas. And you'd certainly want to direct the water away from your house, other buildings, infrastructure such as patios, driveways and walkways, and other vulnerable areas. This should all be in your hurricane-scaping plan.

Since we normally have several days warning that a storm is coming this gives us a chance to plan ahead. In addition to securing your lightweight garden items such as container gardens, in the days before a tropical storm is predicted to hit, also empty your rain barrels to add more capacity during the storm. Many of Florida's tropical storms will drop several inches of rain in only a few hours.

Build groves around lone trees 

Lone magnolia tree (Magnolia grandiflora) in a lawn. Lone tree near a lake fell during a hurricane.
Creating a grove around a lone tree
will help it become more wind tolerant.

It seems to be the default landscaping style in Florida, but lone trees planted in the middle of the lawn are much less wind tolerant than a grouping of trees and shrubs for two main reasons. The first is that the grouping presents a more rounded profile rather than a top-heavy set of leaves on the single trunk. The second reason is that a group of established woody and herbaceous plants will have interwoven surface roots which make the whole group more wind tolerant. I describe the process of building a grove around a tree in my article, Habitat gardening.

In addition, the woody plants and larger understory plants such as bunching grasses will soak up much more water than a lawn due to their larger leaf surface areas and their resulting higher transpiration rates. Transpiration is the process of the water being absorbed by the roots and then transported through the plant to the leaves where 90% or more of the water evaporates into the air. A mature oak tree can transpire more than 400 liters of water on a hot summer's day. For more details on transpiration and other life cycles in forests read my article: Transpiration: Forests' most important service.

When planting container-grown trees, rinse the roots to reveal any coiling roots and to make sure that the roots are spread out as far as possible so they will be more wind tolerant. I explain reasoning and the process in this article

Healthy soils absorb more water

Healthy soil with an assortment of non-poisoned plants absorbs more rainfall per hour than high-maintenance, frequently mowed monoculture lawns.
Fogfruit (Phyla nodiflora) in a lawn needs less mowing and has extensive roots, which helps that lawn soak up more rainfall.

High maintenance lawns that are routinely treated with fungicides, herbicides, and insecticides will have thin poor soils since those treatments kill off the majority of the soil's microbes, which are an important part of a healthy soil ecosystem. All those pesticides are not particularly good for the turfgrass either, so the lawn-care companies apply synthetic fertilizers to keep the grass alive and to push it to grow faster so that it needs mowing more often. And here in Florida, where most turfgrass goes into dormancy for the winter, the lawn care people over-seed it with winter rye grass, so that they have something to mow year round. This may be a profitable business practice for the lawn care companies, but it's terrible for the soil and it pollutes nearby waterways with both pesticides and nutrients that have been causing algae blooms and fish kills. 

In addition, when it rains on a lawn like this, it does not absorb nearly as much water as less-frequently mowed area with a wide variety of plants growing in a non-poisoned soil filled with humus and microbes. These plants will have more extensive root systems compared to the high-maintenance lawns on life support. One term for such a mowed area is a "freedom lawn" since it's free from all those pesticides and free from the synthetic fertilizers. I explain much more about this in my article: Our freedom lawn

Preserve mangrove forests and other shoreline
ecosystems because they provide protection
from storm surges and onshore winds.

Preserve coastal ecosystems

Florida's coastal ecosystems including mangrove forests, saltmarshes, barrier islands. and others provide significant protection from storm surges and onshore winds. Keeping them in place or restoring them will make the whole coastal region more resilient when hurricanes strike.

This is usually more of a community-wide action, where you and your neighbors can work to support efforts to preserve and restore coastal ecosystems. It's been shown that both mangroves and saltmarshes will keep up with rising seas so they will continue their protections for generations to come. Here's a good example: The Snook Islands project in Palm Beach County. 

Stay safe!

After Idalia passed through, we were lucky that it passed to our north and west. We received only .7" of rain and only small branches and leaves blown down. I added some of those raked leaves to the top of my compost pile for a nice green layer and to sequester some of that carbon. 

So please stay safe during our hurricane season, and I hope that this post will help you create a safer, more wind-tolerant landscape. 

Green Gardening Matters,
Ginny Stibolt

I also covered hurricane-scaping in "Sustainable Gardening for Florida."


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