Our Sustainable Garden: Getting to the Root of Things

The holidays have passed, friends from out of town have come and gone, and I am eager to bask in the cold and sunny moments that a Louisiana winter never fails to offer. These moments, for me, are best found fishing the marsh, romping through the leafless woods, and furiously tearing apart my garden at least twice—the past year’s growing season leaving me filled with new inspiration and an entirely new set of garden sentiments I hope to express and experiment with.

Winter, when our plants are dormant, is a most excellent time to plant our perennials and woody plants. Now is the time to plant, divide, and rearrange within your garden. I often find that this surprises people; there tends to be a fear that freezing temps will harm the new plant. This can be the case with tender tropicals, but as far as cold hardy and native plants are concerned, the case is quite the contrary. The plant is now dormant, making it much more durable. 

Plants, like humans, are animate beings, and there are infinite factors that might affect their vitality throughout the life cycle. When planting, perhaps the most important factor to address is the root system. The loosening of roots should be integral to all container-grown plantings, and it is especially imperative to planting container-grown trees. 

[Find more advice from Jess Cole's gardening column, "Our Sustainable Garden".]

Why Loosen Your Roots?       

Though the history of the terracotta plant container can be traced back to ancient Egypt; the advent of plastic in the twentieth century produced the black nursery pot. Plastic pots are cheap and lightweight, and their invention revolutionized the travel of plants between grower and consumer. Plants can now be moved all over the continent in a quick and affordable manner, but alas, oftentimes the most convenient things in life are not the most sustainable.

Forever and always, my greatest garden teacher is the surrounding natural world. One can look to our natural systems (our forests, meadows, waterways, clouds, etc.) and find endless ideas and solutions to inform your garden. From this perspective, let us look to the natural world and see how roots naturally thrive.

When plants grow naturally in the earth, they germinate where conditions are favorable to them, and they rarely move from this spot of germination. In most cases, the roots of a tree, shrub, or perennial have endless space to grow, both laterally and vertically, as needed. By comparison, root systems of container-grown plants are deeply affected by factors at both the nursery and the final landscape environment—living for years in circular hot black plastic, being up-potted numerous times, and traveling large distances for sale.

Plants do not like to grow in circles. When a plant is grown in a container, it can easily grow “root bound”. When transplanting, loosening and pruning a plant’s roots is essential to avoid compromising the plant’s overall health, stability, and establishment. 

Skipping this step, for example, can make a tree susceptible to “girdling roots” that circle the main trunk, causing pressure that in turn impedes both nutrient and water transport between leaf and root systems. 

The discourse on root pruning can get lengthy, intricate, and just dang nerdy. But ultimately, it's a simple concept: lets free up these living plant roots that have labored too long in plastic pots. Annuals and perennials usually live a shorter life in a plastic pot and can benefit from a simple loosening or “breaking up” of the root mass. Shrubs and trees, on the other hand, have lived a long life in those pots, some moving up in size year after year without proper pruning between new homes; and they might require more extensive pruning. 

How to Prune Your Roots

Scruff up the roots well with a trowel (or even better a sharp hori hori—if you do not already know this Japanese garden spade/knife, you are missing out!). Use hand clippers to prune any circling roots, focusing especially on cutting away the outer circling mass you see when you remove a plant from its container. Otherwise, the plant will continue to grow in a circle instead of extending its roots out to then receive the water and nutrients it needs to live a flourishing life. 

This method, and other valuable tips on root pruning, can be attributed to the experts at the tree-focused nonprofit Baton Rouge Green. Great info on the matter can also be found online from Dr. Ed Gillman with the University of Florida. 

Alternatives to Container Growing

Of course, round plastic pots are not the option for growing plants. I personally utilize two other methods of starting perennials and trees. A brief explanation of these follows:

Soil Blocks: I learned this method from revered organic farmer Eliot Coleman, and saw it firsthand with veggie growers in France, where old school gardening traditions remain widely respected and utilized. Soil blocks are squares of compressed soil pressed out of a mold; these squares can replace the use of plastic plug trays or four-inch pots. Plant directly into the soil block, using it as both the soil medium and the plant container. The practice can be traced back a thousand years to Central America; some form of it, historically, has been used in many different cultures. Keep the blocks moist to help hold everything together. Though there is a learning curve, I’ve found it absolutely worth the struggle, and now start all of my veggies, annuals, and a large majority of my perennials this way.

Bareroots: This method involves sowing seeds directly into the ground to then be removed (anywhere from six months to six years, depending on your goals) down the road during the plant’s dormant season. Again, when plants are dormant, they are less susceptible to stress. Therefore, transport is easy, as long as the root system is kept slightly moist. Growing trees directly in ground also requires far less water, meaning this type of growing is less susceptible to drought.

Both of these methods are simple and offer us healthier root systems, and therefore, healthier plants. They are practices that have been around, in some form or another, for thousands of years. This is a recurring theme within my garden work. The “cheap and easy” methods are often worth ditching for more thoughtful, old-school ways that have been proven sustainable before “sustainable” became a buzzword. 

Read about Jess Cole's February Plant Spotlight, The Louisiana Trillium, here.