The Garden Professors™

If you live in a place where water falls from the sky during summer this blog is perhaps not so helpful. However, gardeners in much of the western United States will suffer this summer from hot days (sometimes record breaking) and will need to irrigate their gardens and trees in order for them to survive impending drought conditions. The ongoing drought has drained reservoirs and flows of rivers are down or, in some cases, dry entirely. Due to water scarcity, purveyors are restricting water use outside of homes and in some cases curtailing all landscape irrigation. Using water wisely in the landscape has never been more relevant than now. In this blog post we’ll continue to explore saving our gardens from drought and touch on water use, water demand and plant stress.

Good news — Bad news

The good news is that the longest day of the year was last month. That means that the days are ever so gradually getting shorter. As days shorten, plants use less water. Water use is tied directly to photosynthesis and when the lights are out there is no photosynthesis. Shorter days mean less demand for water. The bad news is that we may have record breaking hot days ahead. Plants become susceptible to wilt, sunburn and dieback during very hot weather. The best way to prevent this is to ensure that roots are moist during very hot weather.

Mediterranean Climate

It turns out that in Ventura, CA the longest day of the year is one of the historically driest months (least rainfall) and the shortest day occurs in a month with more rain than average. This is a classical Mediterranean climate, the rain falls when we least need it for thirsty plants. Plants may not use all the water that falls in winter but soil is leached of salts and deeper soil layers are filled with water. Large woody plants can utilize this deeper soil water in drier months.

Stress

What is not obvious is that stress, especially water stress, is not highest on the longest day but occurs and builds later in the summer and fall months. This is because water is slowly depleted from soils over time. Water use is compensated by irrigations during dry months so stress may not build depending on the effective use of irrigation to keep plants hydrated. Plants and gardens that are less reliant on irrigation build stress over time CUMULATIVELY until they are irrigated or rain falls again. So after the spring rains stop, the “stress clock” starts ticking and keeps building until rain or irrigation happens again in the fall or winter. It is no wonder that symptoms of stress such as wilt, sun burnt leaves, leaf fall and plant death occur in late summer when cumulative stress levels overcome plant physiological limits. Late summer often is the time when the hottest days occur and heat stress in addition to drought stress adds to the struggle for garden plants.

Save your plants in the fall from deadly stress

In the late summer or fall months plants are most likely to die of drought induced stress. This can be forestalled by irrigation applied in August which will reset the stress clock to lower levels. Stress won’t return to low wintertime levels because irrigation water is often of less quality than rain water. The salts in the irrigation water raise the osmotic potential of soil water creating another kind of stress. When it rains, these salts are washed from soil and plants are at their lowest stress levels.

Monsoons (see recent blog by Pam Knox) provide arid climates with stress relief when plants growing in hot deserts most need it. Many plants come out of dormancy or germinate only after the onset of summer rains. While monsoonal moisture can be unpredictable usually some rain falls in the desert southwest. In years when the monsoons don’t come or provide only low amounts of water, some trees or other woody plants even cacti, may die from stress.

Monitor your plants for stress as long dry periods or hot weather get longer and hotter. Apply water strategically to take off stress. Irrigate deeply by soaking the root ball(s) of the plant(s) you want to save. Established plants are pretty tough and can survive adverse periods, newly planted specimens not so much. They must be irrigated frequently just like they were in the nursery until their roots are will grown into site soils. For those of us living in a Mediterranean or monsoon climate we should wait until the onset of a wet period is near before installing new plants.

This Independence Day weekend blog post is about John Bartram, the American gardener and botanist who revolutionized gardening.

John Bartram was born a third generation Quaker on a farm in Darby, Pennsylvania on March 23, 1699. While he had no formal education beyond the local school, he was interested in medicine and medicinal plants. Stymied by the lack of local medical schools, his interests gradually turned to botany and he became one of the first practicing Linnaean botanists in North America.

In 1728, Bartram purchased 102 acres of farmland and 10.5 acres of marshland along the Tidal Schuylkill River from Swedish settlers. After establishing his farm and building his house, he laid out his first garden across six or seven acres on a terraced slope leading from the house to the river. His farm and collections expanded over time and have since been recognized as the first botanical garden in the USA.

Bartram made many plant collecting trips, the first documented one to the “Jerseys and Schuykill mountains” in 1735. His many travels by boat, horseback, and on foot, took him to New England, south to Florida, and west to Lake Ontario. While traveling he collected seeds and plant specimens, assessing how best to cultivate them back home in Philadelphia and how to share his discoveries. Other Colonial-era plant nerds supported his efforts and shared unique plants from their own collections.

Through his seed and plant sharing network Bartram became associated with Peter Collinson, an English merchant, fellow Quaker, and Royal Society member. Collinson, also a plant lover, shared seeds and plants with fellow gardeners, many well placed in British society.

Encouraged by Collinson, who eventually became his chief agent in London, Bartram established an international trade in North American seeds and plants packed carefully in wooden “Bartram’s Boxes” which were shipped in the fall. For five guineas, clients received a container of generally 100 or more varieties of seeds, as well as occasional dried plant specimens and other natural curiosities like bird nests and rocks. Despite the hazards of a sea voyage, many arrived safely to their destinations, where they established a new palette of American colors and shapes within European gardens and landscape.

Bartram’s nursery business continued to grow and thrive with sons William and John Jr. joining the business. Bartram and William continued their plant collecting journeys around North America. In October of 1765, after becoming lost on one of their trips near the Altamaha River in southeast Georgia, they came across the “rare and elegant flowering shrub” Franklinia alatamaha. Of course they collected specimens, which is fortunate for us as the plant appears to be extinct in its original native range. It survives today in cultivation because of the Bartrams’ efforts (you can read this interesting article for more on the topic).

After lobbying by Collinson and Benjamin Franklin in 1765, King George III granted Bartram a pension of £50 per year as the King’s Botanist for North America, a post he held until his death. In this position, Bartram shipped his seeds and plants to the royal collection at Kew Gardens. Bartram also contributed seeds to the Oxford and Edinburgh botanic gardens. In 1769 he was elected a foreign member of the Royal Swedish Academy of Sciences in Stockholm.

Bartram, the “Father of American Botany,” died in 1777. His sons, William and John Jr,. continued the family business of North American plants after the American Revolution. A total of three generations of the Bartram family continued to operate and expand the botanic garden. It was considered the major botanic garden in Philadelphia until the last Bartram heirs sold out in 1850. America’s oldest surviving botanic garden was dedicated as a 50 acre National Historic Landmark in 1963. Be sure to visit when you’re in the area.

Interested in learning more about John Bartram and other revolutionary gardeners of his time? There’s an excellent book by Andrea Wulf, “The Brother Gardeners“. I highly recommend it.

Happy Independence Day and here’s to garden revolutions everywhere!

“Some people feel the rain. Others just get wet.”—Bob Marley

If you follow the weather news carefully, you might have noticed a little factoid in this week’s headlines: Mawsynram, Meghalaya, in northeastern India reported the highest all-time single-day rainfall in the month of June on the 17th. At 1,003.6 mm (39.5 inches), it eclipsed the previous highest rainfall of 945.4 mm (37.2 inches) recorded on June 7, 1966, according to the Guwahati-based Regional Meteorological Centre (RMC). The extraordinary rain fell as part of the Indian monsoon while other parts of the country are in drought and have received less rain than usual so far, although monsoon rains have been picking up. Seventy percent of India’s rain comes from the monsoon so if the monsoon fails, agriculture and water supplies are severely impacted.

What is a monsoon?

If you ask a layperson what a monsoon is, they will probably tell you something about very heavy rain and might even mention that it is a seasonal rain event. The most famous monsoon occurs in India each year, but monsoons are found in other parts of the world as well including China, Africa, and the United States. In the U. S., the Southwest Monsoon season usually starts in mid-June. If you look at the weather forecasts this week, it is right on time. This period is characterized by heavy showers and strong moisture flowing into the region bringing wet conditions to areas of the country that seldom see rain in other seasons. But officially, a monsoon is not the rain itself but a change in the atmospheric flow driven by differences in land-sea heating in summer. Rain falls in one half of the cycle but the switch to the opposite flow pattern often means dry weather as high pressure forces moist air away from the land.

How a monsoon forms

Monsoons are driven by temperature differences between land and water caused by heating from the sun. The hot land causes air over it to rise, leading to a net low-pressure area. Air rushes in from other locations to even out the pressure. On a small scale this type of circulation occurs as a sea breeze that you might feel along the shores of a large lake or ocean. The land heats up much more quickly than the water during the day, causing rising air over land that creates a circulating cell of air that blows cooler air from water to land in afternoon when the temperature difference is strongest. You can often feel a sea breeze front as the cooler air moves inland, and sometimes thunderstorms form along that boundary between land and marine air masses.

In a monsoon this pattern happens on a much larger scale. In Southeast Asia, for example, the whole of India and surrounding countries heats up under the direct summer sun much more than the Indian Ocean to the south. That causes air to rise over the land and pulls in air from the ocean to the south. In India, meteorologists track the progression of the monsoon “front” from south to north across the region and celebrate when the monsoon finally arrives, bringing copious showers that bring much-needed rain to India. In the Southwest U. S., the coming of the monsoon is also watched carefully because it provides welcome moisture and cooler temperatures to the region due to increased cloud cover. More than 50% of the annual rainfall of Arizona and New Mexico falls during the Southwest monsoon, so it is an essential part of the seasonal cycle. But it can also bring lightning strikes that spark forest fires in areas that receive little rain, causing widespread destruction in those areas.

How monsoons are important to gardeners

If you live in a part of the world that is affected by monsoons, you need to be prepared for the variation of rain over the course of the year. During the wet part of the monsoon, you may experience very heavy rains that can erode your garden and wash out plants. If you have low-lying areas, roots can be affected by standing water to the detriment of your garden plants unless you put in good drainage. Conversely, you need to also be prepared for periods with little to no rain at all, sometimes for significant periods of time. That means you either need to use plants that are adapted to the wet-and-dry monsoon conditions or be prepared to irrigate them regularly to keep them in good shape.

Monsoons are one example of how earth’s geography, including sun angle, land-sea distribution, and differential heating all work together to create diverse climates across the globe. They have inspired local music and literature as essential elements of culture in India and other parts of the world. And they serve as a critical driver of plant life by providing needed moisture to growing plants and crops. So for those of you who live in monsoon climates, do a little dance when the rains begin. The monsoon is here!

Other resources:

British Meteorological Office video: What is a monsoon?

NOAA SciJinks: What is a monsoon

Monsoon video series of SW monsoon imagery set to music by Mike Olbinski—spectacular!

Chasing the Monsoon: A Modern Pilgrimage through India—my favorite book on tracking the monsoon through India

Mmmmm, fresh summer tomatoes. They’re great sliced, diced or made into salsa or sauces. There’s nothing like picking one right off the vine, popping it in your mouth and splat! You now have tomato all over your shirt.
“No problem,” you think, “it’ll come out in the wash.”

Fast Forward to Laundry Day…

As you’re putting your freshly washed and dried laundry away you notice that tomato stain is still there. So you toss it back in the hamper for next time.
Several laundry days later, that tomato stain is hanging on. You decide it’s time to get serious.

So you soak and you scrub.
And you soak and you scrub.
And still that stain refuses to budge.
(Rather poetic isn’t it)

You’re about to go all Lady MacBeth on it!

But thankfully you regain your senses before ruining the shirt.
“What’s the deal with this *&#^%*$ tomato stain!” you wonder. You’re almost ready to designate it your “special tomato shirt,” which admittedly would be handy for those “S’ketti Night Socials” at the county fair, but you’re not quite ready to give up yet.

Nil desperandum my friend! Professor Sprout has some special botanical knowledge to impart that will make your Expelliarmus spell work.

Why Are Tomato Stains So Difficult To Remove From Fabric?

Tomatoes contain multiple pigments: chlorophyll, carotenoids, xanthophylls, and betacarotene. The trouble maker is a bright red carotenoid, lycopene. It’s an approved food coloring and is found in other red fruits such as watermelon, red carrots and papaya. Despite it’s being a carotene, it has no vitamin A properties.

Why Does Lycopene Stain?

Lycopene is not a water soluble pigment, it’s only soluble in fat. In other words, it’s hydrophobic. Hydrophobic molecules cling together to minimize their contact with water, so the pigment hangs onto whatever surface it’s on. Add the nooks and crannies of fabrics, especially natural ones, and it’s hard to get it to release its hold. The hydrophobic nature of lycopene also means that it resists attempts to clean it with just soapy water. The high temperatures of a washing machine can drive stains even deeper.

So, How to Remove a Lycopene Based Stain?

The trick to removing a lycopene based stain from fabric is to treat it like a lipid stain (lipid = fat or oil). Bleach won’t work and often regular spot treatment or laundry detergent won’t either. If it’s an old stain you might need to put a drop of regular cooking oil on the stain or spritz it with an oil based pan spray. What you’re wanting to do is get the lycopene back into an oil base which can then be washed out.
Another thing that works is to hit the stain with a solvent based stain remover. There’s a popular brand of carpet cleaner that works quite well for this. We can’t make commercial recommendations here but if the name Sp*t Sh*t rings a bell well, aren’t you clever. As with all stain removers test on an inconspicuous area beforehand.
If the stain has been through several wash loads, it make take a few wash loads to remove it. But the above method will work.

Bonus round!

Lycopene also stains plastic which is why the container you reheated the Aunt Mamie’s spaghetti sauce in is red. The good news is that lycopene will oxidize so you can soak the stained plastic with a bleach solution which should remove it.

So there you go. Enjoy tomato season and don’t worry about the laundry!

Yikes!

Drought of epic proportion is imperiling many western states this year. For the first time some water districts have proposed curtailment of all exterior irrigation, no applied water will be allowed outside of residences. There are public forums are scheduled with experts and officials giving advice. Of great concern is the certain loss of turfgrass swards but far more concern is being expressed for the loss of trees.

Don’t assume your trees will die of drought!

Most established trees are resilient, they have built in drought avoidance and tolerance strategies. It helps to understand these processes and know the symptoms of drought injury in trees. Almost all trees will stop growing when they enter drought conditions because there is not enough water to produce the turgor pressure necessary to expand cells. While growth may slow, trees have root systems that help prevent them dying of drought. The root systems, while mostly in the surface layers of soil, also explore greater depths where they can extract water from larger volumes of soil. So even though soil may be dry on top, trees have greater access to moisture than is obvious from above. Trees also have mycorrhizal fungi that help them extract water bound tightly to soil. When these strategies become limiting, tree roots produce abscisic acid that flows to the pores in leaves and closes them to reduce transpiration. If drought continues, many trees will drop leaves entirely to help stem and root tissues survive, thus avoiding drought. These mechanisms are all controlled by tree genetics and their ability to ameliorate drought effects is variable. Some trees are just more drought resistant than others.

Don’t plant new trees in the Summer!

Now is not the time to plant trees. As we near June 20th (the longest day of the year) demand for water is also greatest as sunlight drives photosynthesis and thus water use by trees. Newly planted trees all need irrigation to help them establish. During drought years, wait until later fall months (when rain is more likely and day length is decreasing) to schedule planting.

Don’t fertilize trees during drought!

Fertilization is the last thing you want to do during or at the onset of drought! Fertilizer (organic or inorganic) contains salts that increase the osmotic potential around roots. This alone can create “physiological drought” as water is drawn out of roots into soil solutions. Fertilizers should only be applied when known deficiencies are present and water is abundant enough to dissolve the applied materials.

Don’t prune trees during drought!

Pruning removes terminal buds that regulate growth of the canopy. When they are removed by pruning, lateral buds are released to grow. Stimulating new growth during drought is a disaster for trees. Don’t do it! You may falsely think removing branches in a tree canopy will save water. Most trees can regulate their own water loss as discussed above or by dropping leaves as necessary when dry conditions ensue.

Do not install artificial turfgrass

Artificial turfgrass is not a solution for hot dry conditions. In some cases it may exacerbate the situation. Artificial turfgrass does not allow percolation and capture of water since it covers soil. Artificial turfgrass does not transpire, so landscapes will not be cooled by it. Trees adjacent to artificial turfgrass have less ability to access water than those adjacent to a mulched area.

The longest day in June may not be the most stressful for trees

When water is scarce, it is important to apply it strategically to reduce tree stress. Even though June has the longest day and potentially tress will transpire the most, it may not be the most stressful time for trees because water may still be available at lower soil levels in June. As we enter later summer and early fall, stress builds as available water is depleted from tree root zones. Deciduous trees will lose leaves but evergreen trees or trees that can’t shed their canopy may begin to enter their permanent wilting points. This is usually proceeded by wilt, dieback, and loss of color. This is a critical point where strategic water applications can help trees through a critical period.

Do apply Arborist Chip Mulches

Mulch is a critical drought survival tool for trees. It is best if mulch is already in place but it is never too late to apply it. Mulch changes soil structure allowing for more water storage. Over time, mulched soils become more drought resilient. In the short term mulch prevents evaporation from soil surfaces so that applied water stays applied in the soil and is not lost. Coarse wood chip mulches prevent weeds that use water thereby keeping more moisture in the soil. Wood chip mulches support the mycorrhizal fungi that help trees survive.

Do “top up” existing mulched areas around trees

Mulch breaks down as it is supposed to. It is important to keep mulch layers intact by occasionally adding to mulch layers. If you have not done so, add mulch before summer gets too far along.

Do remove lawns or shrubs that are no longer sustainable in the landscape with care.

Water restrictions, hot weather and dry soils culminate and can greatly damage landscapes. If landscapes are over planted or there are unwanted/unnecessary plantings they can be removed to save the water they would use. Be careful not to expose existing plants and trees to bright sunlight as this may cause them harm from sunburn. Be careful removing turfgrass swards and the irrigation that accompanies it because adjacent trees may be reliant on the excess applied water. A slow dry down and mulch over process may be the best approach to save valuable perennial plantings near unsustainable turfgrass.

Do monitor your trees for signs of impending drought stress. and apply water in a timely manner

Wait until leaves start to turn yellow prematurely or canopies show wilt symptoms to apply water. As drought symptoms develop, consider a slow application of water by a dripping hose (moved frequently) or a low flow sprinkler that applies water only as fast as the soil can take it in. Apply water at night to cut down evaporation loss. Continue to monitor for further drought symptoms and spread out irrigation as needed to conserve water.

Do turn off your valve controllers to avoid over application of water.

Don’t let electronic devices make irrigation decisions for you during water restrictive drought periods. No electronic system completely understands the stress conditions around trees and will not be able to accurately predict when to irrigate. It is best to make these decisions based on your own assessment of conditions and resources available. Many “irrigation clocks” rely on regular frequent applications of water to keep soil moisture supplied. Frequent short run cycles replace water used by plants. During drought restrictions, controllers need to be reprogrammed to apply less frequently but for longer runs (to the point of run off) or not used at all if the sprinkler emitters put out too much water. Targeted water applications will likely be necessary and valve controllers will need to go “dormant”, i.e., turned off.

Be hopeful

Droughts come and go, right now they keep coming. But there are many examples of trees that only receive rainfall, no applied irrigation and yet survive well. Don’t assume your trees will die of drought. This may be a time to remove trees that are not adapted to growing in your area and drought conditions will reinforce this. European Birch are certainly disappearing from many landscapes this year in Southern California. Increase the use of mulch, apply water strategically, and consider planting more adapted trees late in fall or winter when water is available to support establishment.

While drought is part of the natural cycle of the climate and many native plants depend on drought to propagate, it is the bane of gardeners everywhere because of the increased need for water. I have previously written about the four types of drought. Today I thought I would focus on drought monitoring and a way that you, as a citizen scientist, can help report local conditions that the official drought monitor authors can use to fine-tune their depictions of drought. This will be especially helpful this year with so much of the country in drought conditions.

What is the Drought Monitor?

The U. S. Drought Monitor (I’ll call it the DM here) is the source of the “official” drought status across the country. Of course, you don’t need an official status to be in drought but it is commonly used by media, government agencies, and scientists to categorize the strength of drought over time and space. The official DM map shows a single map for the United States updated each Thursday morning that is color-coded by five levels of dry conditions ranging from Abnormally Dry (D0) to Exceptional Drought (D4). The drought categories show experts’ assessments of conditions related to dryness and drought including observations of how much water is available in streams, lakes, and soils compared to usual for the same time of year. If there is no color shown then that region is not officially in drought. If it is in D0 (bright yellow on the map), then it is considered dry but not currently in drought. Often a D0 designation means either that drought is imminent or that there are lingering impacts from a drought that is ending. You can read more details about what kinds of impacts are seen in each level of drought and how the weekly map is produced on their “About” page. You can also find links to state-specific impacts there, since a drought in the Southeast does not look like a drought in the Southwest, for example.

Issues with the DM

One of the shortcomings of the DM is that there is just one weekly map that is supposed to be a complete depiction of drought across the United States. If you read my last post on drought, you know that drought comes in different varieties that occur over different time periods. Agricultural droughts are caused by dry spells and hot temperatures during the growing season and can come on very quickly (“flash droughts”), while the long-term precipitation averages might not reflect that lack of water and so would not be captured on the DM map. Hydrological drought is related to a long-term lack of rainfall that reduces the water levels of lakes, streams, and reservoirs over many months or even years. It might not affect gardens and farms significantly as long as enough rain falls at regular intervals to keep the plants alive.

While the DM was not created to be a legal means for defining drought, it has become one in legislation passed by Congress to provide drought relief to affected farmers. The program I deal with the most in my work is the Livestock Forage Disaster Program, which provides a payment to forage producers to offset economic losses if drought stops the growth of pastures, especially early in spring when hay supplies are depleted over the winter. The law is written in such a way that if the drought level is severe drought or worse (D2+) for eight consecutive weeks, then they can receive one month’s payment for the lost forage. If it is in extreme drought (D3) somewhere in their county for any time during the growing season, then they can get payment for three months.

As you can imagine, when a flash drought happens and the grass stops growing the forage producers need the relief to help purchase hay to keep their livestock alive. But the DM does not typically depict this quick-changing drought because it is based on longer-term indicators that do not change much over just a couple of weeks. So there is a disconnect between what the DM is showing and how it is being used for legal purposes, at least in the case of forage and pastures.

As you might guess, this results in some attempts to game the system to make it look drier than it is to get the DM authors to declare a D2 or higher drought. The authors tell stories about being harassed over the phone about where they draw the drought lines on the map, finding observers who report no rain when radar clearly showed it occurred, and other creative ways to make the drought appear worse than it is so they can get access to the payments they need.

How can you monitor and report drought?

Here is where you come in: Citizens like you have an important role to play in keeping an eye on local vegetation and monitoring it for signs of drought or impacts from saturated soil. Gardeners are already especially attuned to what conditions are normal and what conditions are not. Folks who monitor local climate conditions are much like storm spotters who monitor weather systems for strong winds and tornadoes—they watch how things evolve over time and provide that information to the authors of the DM and others who need hyper-local information, although on a much longer time-scale that storm spotters. If you are a CoCoRaHS rainfall observer, you probably already know about the Condition Monitoring report that you can submit through their website. Another great place anyone can submit official Condition Monitoring Reports (called CMOR which is pronounced “see more”) is the CMOR site on Drought.gov.

As you can see from the map above, there are many parts of the country with no CMOR reports to provide information about conditions at those spots. By providing these reports, you are helping the DM authors with unbiased, fact-based local observations that can support other drought indicators like streamflow, precipitation deficits, and groundwater losses. Thanks for providing this service to the DM authors and other scientists!

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?

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.

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.

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.

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.

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

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.

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.

Which brings us back around to B&B trees.

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.

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