Burlap, the fashion fabric of the gardening world.

Cheap, lightweight and easy to manipulate, burlap has become a popular way to protect transported B&B trees from the nursery to their planting site. To add justification for its use it’s also touted as biodegradable. “No need to remove it!” or “Leave it in place to protect the root ball.” and other such phrases are often tossed at the unknowing homeowner but are they laudable? Let’s investigate.

Hessian soldiers ca. American Revolutionary War – what do they have to do with burlap?

Carl, J.H., “Regiement von Bosse” (1784). Prints, Drawings and Watercolors from the Anne S.K. Brown Military Collection. Brown Digital Repository. Brown University Library.

Burlap is the North American name used to refer to a fabric known as hessian in other parts of the world (except in Jamaica where it’s called crocus.) “Hessian” is attributed to the historic use of the fabric as part of the uniform of soldiers from the former Landgraviate of Hesse and its successors, including the current German state of Hesse. Soldiers from these areas were called “Hessians”. If you recall your American Revolutionary War history, the name Hessian might ring a bell.
While the word burlap might bring to mind the image of a coarse brownish material, Hessian fabric is available in different types of construction, form, size and color. Even though the two names refer to the same fabric, we’ll stick with “burlap” for our discussion.

Illustration of Corchorus olitorius, 1828, William Jackson Hooker (1785-1865)

Burlap is produced from two Corchorus species in the Malvaceae family. The main fiber source is C. olitorius but the fiber from C. capsilarius is considered superior to it having a finer texture. Both plants are called jute, which also applies to the fiber.

Jute grows best in a warm, wet climate. A long monsoon season followed with consistent temperatures over 75ºF/ 25°C and relative humidity of 70%–90% are ideal. Jute requires 65″-80″/160–200 cm of rainfall yearly plus extra during the sowing period. The plants prefer river basins, alluvial or loamy soils with a pH range between 4.8 and 5.8. Periodic flooding or marshy conditions are well tolerated. ~85% of the world’s jute is grown in the Ganges Delta.

Farmer collecting bundles of harvested jute to be taken for initial processing in West Bengal India. CC image

When ready to harvest, the jute is cut off at the soil surface and gathered into bundles for transport and processing. To extract the fiber, the jute bundles are retted. There are a variety of retting processes: mechanical (hammering), chemical (boiling & applying chemicals), steam/vapor/dew retting, and water or microbial retting. Water or microbial are the oldest forms and most often used.

Jute bundles being water retted. The bundles are kept submerged with logs. CC image

When the jute is well retted, the bundles are hit with a long wooden hammer to loosen the fibers from the core. After loosening, the fibers are washed with water and squeezed dry. The extracted fibers are further washed with water then hung up to dry. When dry they’re tied into bundles to be sold at market.

Jute fibers drying. CC image
Jute market. CC image

So what does all of this have to do with B&B trees?

Image by USU Extension

Burlap, even a tightly woven burlap, “breathes.” This gives it a strong resistance to condensation, moisture, and fungal growth. Jute is a hard fiber which makes it very durable and jute burlap is wear, tear, puncture, and stretch resistant. Breathability plus condensation, moisture, fungal growth, wear, tear, puncture and resistance to stretching are all qualities which make burlap a good choice for the transport and storage of goods and as a geotextile.

“Natural” burlap is lightly treated with an emulsion, usually a cheap plant based 3:1 water and oil mixture, as a part of the weaving process. The mixture makes the fibers easier to handle and move through the loom, and helps reduce waste. The water does most of the work; the plant-based oil just prevents the water from evaporating so quickly. Burlap made with plant-based emulsion is required for food safety, storage and transportation and aren’t as long lasting as the other type of burlap. They normally last about three years in use but can take up to a decade to decompose.
Yes, you read it correctly.
“Natural” burlap can take 10 years to fully decompose.

Burlap sacks of green coffee beans.
Image credit: Tim Pannell, Mint Images/Science Photo Library
 

The qualities that make burlap good for food stuff transport also make it useful in the construction, landscape, government/emergency services, and outdoors/sporting sectors. Fabric woven for use in these areas is treated differently; the emulsion used on it during weaving is usually petroleum based. This emulsion is designed to add more water, rot, and gnawing pest resistance to the fibers prior to weaving. It can leave the fabric feeling “sticky” or “coated” and tends to attract dust and dirt. It also has a peculiar chemical aroma to it. The finished fabric is often treated again to add even more resistance. So, the fibers are treated prior to weaving and then often again afterward. A double whammy, so to speak. “Treated” burlap is very long lasting, durable and can be stored for years in a variety of conditions without the fibers weakening. It can last for decades, above and below ground.

A hay bale ground blind covered with water and wind resistant burlap.
We didn’t know this was a thing.

Which brings us back around to B&B trees.

Image credit: Matt McClellan

Guess which burlap is used almost exclusively in the landscape industry, the “natural” or “treated” ?
If you guessed “treated,” you’re correct! Its durability, ease of use, and excellent storage qualities makes it the #1 choice for transporting nursery trees.
Unfortunately many, if not most, plant people don’t know about different burlap types and are relying on out-dated information. (This is true in more areas than just burlap, but those are other issues.)
Try asking if the burlap on that root ball is “natural” or treated and see what their response is. Feel the fabric yourself. Does it have a tacky feel, do your fingers drag on it, does it seem to attract dirt or dust? Does it have a chemical or petroleum odor to it? These are all indicators of treated burlap. Both natural and treated burlap degrade slowly. Leaving burlap on the root ball will only encourage circling roots and probably doom the tree.

Just so we’re not being misunderstood: Wrapping the root ball with burlap for transporting purposes is all well and good.

But you have to remove it at planting!

Let’s do a quick review of the qualities of burlap and how they can backfire when planting trees.
Breathability: not really a problem underground but can cause the root ball to dry out if the tree is exposed to the air for too long.
Condensation and moisture resistant: doesn’t absorb water so the fibers won’t rot.
Little to no fungal growth: isn’t consumed by fungi so fibers stay intact.
Tear and puncture resistance: roots can’t push or force their way through therefore encourages circling roots.
Doesn’t stretch: won’t expand with root growth therefore encourages circling roots. Sound familiar?
Natural” burlap: can take up to a decade to completely decompose all the while negatively impacting root growth.
“Treated” burlap: can take decades. ‘Nuf said.

Bonus round!
Soil factors can also influence burlap decompostion. The decay rate in soil pH levels below 6 is significantly slowed. Low soil temperatures result in a slower decomposition process. Dry soil slows jute fiber break down too and even desert termites don’t care for treated burlap.

A B&B tree is an investment: give it the best possible start you can. Always remove the burlap, wire basket, strings, ties, or any other constrictions you find. And don’t forget to root wash, correct any root problems, and spread the roots out horizontally away from the trunk when planting.

Image credit: George Weigel

For your enjoyment, be sure the sound is turned up so you get the full effect.
https://youtu.be/D9AUnYTol68

Garden Diagnostics

A garden plant with symptoms of an insect infestation

I’ve had this funny feeling that something is just not right in my garden. Can’t put my finger on it, but something is amiss. OMG everything is dying! Help! Garden Death is rampant! Well, a bit of hyperbole perhaps, but over the years I have had many calls from gardeners with great concern for plants or their entire garden based on things they perceive to be going on. I have helped them by trying to diagnose their problems. Thought occurs though that most gardeners should be able to diagnose their own garden problems with guidelines and framework that informs their decision making processes. The problem with solving problems is that often gardeners don’t notice a problem until it has advanced quite far often to the point of no return. So, the trick is to “see” things early so they can still be fixed.

Looking for patterns in your garden can inform disease issues. here all the boxwood are yellow and all the redwoods are brown. See first paragraph! Yikes!

Patterns

The first step to solving garden problems involves looking for patterns in the symptoms that are presenting as the “that does not look right to me” situation. The redwoods and boxwood in the image above are all performing badly and the symptoms are uniform. Uniform symptoms that occur across a population of plant often suggest an abiotic cause. In this case the use of recycled water high in salts has impacted the landscape plantings.

Symptoms are plant responses to a pathogen or abiotic condition

Symptoms

are plant responses, changes in physiology such as chlorosis, and necrosis, spots, coloration or discoloration etc. Foliar symptoms often form when a plants ability to make or utilize chlorophyll is compromised. Symptoms also occur on stems in the form of cankers or dead spots that can ‘girdle’ the stem leading to foliar symptoms in the shoots on that stem. When diagnosing garden problems it is important to look at symptoms carefully and early. This involves understanding what is normal for the plants being grown. Plants exhibit a variety of growth patterns and changes throughout the season so some changes are normal. The trick is to see the early onset of “not normal” symptoms.

Signs are the actual pathogen that is causing the symptoms in the affected plant

Signs

…are the cause of disease. Signs often confirm a diagnosis and give way to control options once a pathogen or other disorder is identified. Finding signs is of the confirmation needed to take some action to fix the problem in the garden. Often fruiting bodies of pathogens don’t form until the host has died or shed leaves that fall on the ground. Many signs are microscopic, but some spores can be seen ‘en-masse’ when inocculum builds up to visible levels. And sometimes symptoms and signs occur together helping to solve the diagnostic problem.

Powdery mildew spores (white) are signs and the broom-like symptoms are typical of the disease that forms in coast live oak.

Canker diseases cause a variety of symptoms and signs. Most cankers only form signs after the stem has died. Early in the progress of disease plants may appear discolored but it is not until later that the signs will form usually after the plant is visibly necrotic

Early symptoms of Ficus canker in Indian Laurel Fig
advanced symptoms of Ficus canker
Signs of Ficus canker disease. The black dots forming on the end of a cankered branch are fruiting bodies that hold the spores of the fungus causing the disease.

Time

…is an important factor in disease progression. Diseases do not happen instantly but form over time. Diseases, if they result from pathogens, have a “life history” where the various stages of the pathogen are formed or survive and accompany symptom development in the host. Early symptoms may be innocuous or subtle. The problem is we notice problems at a single point in time but the problem is often well along or has been developing long before we notice it. Understating the time line of disease or pest formation is important in diagnosing the cause.

Insects

—are often confused with pathogens because they can cause some of the same symptoms as plant pathogens or abiotic disorders. Insects cause an array of symptoms that can be used to diagnose their presence. Some insects related symptoms are: foliar stippling, bronzing and bleaching, leaf spots, chewed foliage, wilting and death of branches or entire portions of a plant or tree and galls. Insects also create signs of their activity such as frass, galleries, honeydew, cast skins, and excrement. Of course the ‘gold standard’ of insect signs is the insect itself which can take the form of adult insects or larval insects, both of which may look very different and affect different parts of a plant.

Frass shown here is a sign of boring insects inside this tree.
Many insects cause their host to grow galls such as this oak apple gall caused by a small wasp
This leaf spot on Lantana camara was long thought to be a fungal disease but is actually caused by a ‘blotch miner’ insect in the genus Liriomyza.

Diagnosis of garden enemies is just the first step in finding a solution to a garden plant malady. Often determining the cause requires some expert help. Your local Cooperative Extension advisor often has experience in diagnosing the most common problems or can find assistance getting answers. With the advent of smartphones that have great cameras we can diagnose many issues remotely with images. Regional expertise is best as pests vary by state and region. The diagnostic prowess is often local–in the county where you live. Start there and widen your research until you feel you have the identification you need to research possible cures.