Cockleburs can cause more than just an inconvenience

I was walking around in the brush recently and noticed thick stands of cockleburs (Xanthium sp.). I tried to avoid them, but before I realized it my pants collected dozens.

People with hunting dogs know all about cockleburs. Long-haired dogs have even more problems. Sometimes prickly burs get so entangled that cutting them out is the only option.

I remember putting up hay and coming home with my fingers full of pieces of these nasty briers. I also recall spending hours removing them from an old collie mutt.

Unfortunately, the discomfort of sandwiching one of these burs in between the skin and another object is not the worst of the problem. The cocklebur plant is poisonous. They are a major problem in crop and pastureland.

Toxicity to animals can occur at different times of the year, but newly emerged seedlings are the biggest concern. Early spring is a problem time in pastures. Sometimes animals can get poisoned later in the year when mature seeds drop and start to grow.

Seeds are toxic too. I don’t know of anyone who would try to eat these spiny things, but pets and livestock might ingest some while trying to groom themselves.

Toxicity is caused by Carboxyactractyloside or CAT for short. CAT interferes with cellular energy exchange. It’s a little complicated, but the bottom line is that even low levels of the compound can cause death. This chemical is not a problem in mature plant tissue.

When I lived in West Virginia I don’t recall many toxicity problems with cockleburs. My in-laws never had any poisonings from cocklebur and their neighbors didn’t either. These weeds were more of a nuisance than anything.

I think there were three primary reasons for this. First, their cattle were never lacking for hay in winter. This meant that the animals had the luxury to eat around the spiny burs and not ingest the seeds.

Another reason was probably because most farmers tried to wait until pasture growth was well established in spring before stocking animals. Placing livestock on them before adequate forage accumulated meant short thin pastures during the summer heat.

Finally, cattle were never allowed on meadows until it was time to feed hay. This meant any cocklebur seeds that germinated were already too mature to cause problems.

Cocklebur is an annual weed and spreads only by seed. Clipping pastures before seeds mature can help eliminate the spread of this weed. Many herbicides can control it, but they might leave residues that could accumulate in livestock.

This is a lesser problem in corn and soybeans as there is normally a longer time period between chemical application and harvest. It is impractical to keep animals from grazing an area for much of the growing season.

Cockleburs are problematic for pets. I doubt dogs would deliberately eat them, but they could ingest seeds by trying to remove the burs with their teeth, That’s the only way they know how. They also can get burs stuck in their tongues. Therefore, I suggest grooming your dog if they bring home a coat full of cockleburs.

Cocklebur plant in late winter

Cockleburs on my jeans

Cockleburs on my coat

Close-up of the burs

Ted Manzer teaches agriculture at Northeastern High School (

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Is manuka honey a wonder cure or another overrated holistic drug?

I was talking to a friend recently about an expensive honey from New Zealand. It’s called manuka honey and it comes from the flowers of the manuka tree. Manuka trees are commonly called New Zealand tea trees and are in the myrtle family.

Raw honey is naturally antimicrobial and has long been used in human and veterinary medicine. My father-in-law used it to treat freshly dehorned cattle. I was shocked when I first saw it.

He removed the horns, which many would consider a brutal process. It really isn’t, because horn removal lessens injury when animals are kept in close quarters.

After removing the horns, he tied off bleeding blood vessels and cleaned the area. Finally, he coated the wound with a thick layer of honey. I can’t recall any surgical sites becoming infected.

I don’t know how much he knew about microbiology. I think he was more concerned about keeping flies from laying eggs. They would die in the sticky honey.

He used local raw honey because it was available and cheap. Raw honey is important since a large percentage of honey in stores has been processed and blended to such a degree that most antimicrobial properties have been lost.

Manuka honey is not cheap. Some medical grade stuff can sell for well over a hundred dollars for an eight-ounce jar. This honey has a high MGO content. MGO stands for methylglyoxal, which is much higher in manuka honey than any other types. This chemical has strong antimicrobial properties.

Pollen from the manuka plant is high in methylglyoxal. However, there is considerable variability. In addition, much honey is mixed from other pollen sources.

Manuka honey that is marketed as medicinal quality is graded on its antibacterial strength called its Unique Manuka Factor (UMF). Values of 15 or greater are much more valuable for medicinal use. Price is much greater, too.

Manuka honey is used to treat acid reflux disease and other digestive system problems like stomach ulcers and irritable bowel syndrome. It also is used to treat tooth decay and gingivitis and it also has been used to combat strep throat.

Not all use is internal. Manuka honey is employed topically to treat skin infections like eczema and acne. Research even shows its effectiveness in controlling MRSA and other serious staph infections.

Burn and wound treatment are other topical uses. Numerous sources also indicate it helps with skin ulcers caused by diabetes. Even ear infections have been treated with Manuka honey. Honeys with higher UMF levels are most often used topically.

Like all honey, manuka is high in sugar and could be a problem for diabetics when consumed internally. In addition, it could pose problems for folks allergic to honey, even with topical treatment.

There are hundreds of articles about manuka honey on the internet. Some promise such superlative results that they are too much for my inner skepticism. Still, due to the sheer volume of research, the product must have some merit. I still suggest contacting your medical professional before jumping headlong into the manuka phenomenon.


Ted Manzer teaches agriculture at Northeastern High School (

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Bald eagles, ospreys have contrasting styles as predators

Not long after I wrote a column on ospreys, I spotted a pair of mature bald eagles on Northeastern’s campus. I’ve never seen any at school before, but I see them occasionally around Elizabeth city and in surrounding counties.

Bald eagles are a bit larger than ospreys. They eat a greater array of food, too. These powerful raptors catch fish, their favorite food, but they also can take down larger prey. They usually don’t, because that’s too much work.

Eagles don’t like to expend more energy than necessary. Like most predators, they don’t usually take unnecessary chances either. Taking on larger prey like dogs and cats could get them injured. Permanent injury to a predator ultimately means death. Fish are safer.

Ospreys usually make a steep dive for their prey. Sometimes they travel as deep as four or five feet into the water, while eagles catch fish near the surface. These two efficient predators have contrasting styles, and I enjoy watching both.

Eagles fly at a shallow angle when approaching the water. They don’t decelerate much. An adult bald eagle can snatch a three-pound smallmouth and keep right on flying. I’ve seen it.

Large mature bald eagle perched in a white pine in downeast Maine

Eagles also like to view their hunting spots from high perches, rather than fly or glide around scoping out food like turkey vultures do. Eagles also don’t limit themselves to living prey. They are opportunistic and will steal food from other predators.

I saw one eating from a deer carcass once. They will also attempt to pilfer food from other eagles in midair. Bald eagles also like to follow ospreys around and steal from them. Since they are about three times the size of ospreys, the ospreys rarely challenge them.

They also hunt in pairs sometimes. A few years ago, I observed a pair of eagles harvest the offspring from a pair of loons. The communication and coordination were incredible. The loons tried desperately to save their young, but they were no match for the eagles.

We ware all familiar with the appearance of adult bald eagles, but many people don’t recognize what younger ones look like. Eagles don’t develop the classic white head and tail feathers until they reach sexual maturity at four-years-old. Sometimes they don’t mature until they are five.

Immature eagles start out mostly dark colored with dark beaks. Their body colored becomes flecked with white until their fourth year. The beak changes to a bright yellow color by year four. During this time eyes also change from dark colored to bright yellow.

Female bald eagles are slightly larger than males. Both work to build nests, which are often over ten feet deep and eight feet across. Eagles, like ospreys usually fortify their nests every year, so after several seasons they are spectacular. No other bird in North America builds nests as large as bald eagles do.

Alaska is the state with by far the highest population of bald eagles. Cold weather is not the reason, as there is a significant population in Florida. Every state except Hawaii now has growing populations of bald eagles.


Ted Manzer teaches agriculture at Northeastern High School.

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Ospreys might be the greatest of all fishermen

I wish I had more time to spend on and around the water. I love to watch the ospreys patrol the skies in search of fish. Some people call them sea-eagles or sea-hawks. In many places, ospreys can only be observed during certain parts of the year, but here in eastern North Carolina they live here year-round.

Forty years ago, sighting an osprey was rare. They faced the same decline as the bald eagle and many other predatory birds. Certain pesticides didn’t break down in the environment very fast. DDT is the one everyone talks about, but there were others.

These chemicals accumulated in the bodies of animals. Those at the top of the food chain became the most contaminated because of a phenomenon called biomagnification. Plants and insects were sprayed and whatever ate them also absorbed the poison. Animals couldn’t rid themselves of these toxins, which became more concentrated. The same thing happened with mercury levels of swordfish and other apex predators in the ocean.

Since about 1970 we have done a much better job reducing chemical contamination of our environment. Eliminating lead in gasoline means there is now far less lead in our air and waterways.

Pesticides and other chemicals never really killed many ospreys. They caused females to lay eggs with thinner eggshells, and the birds were unable to roll and incubate the eggs without breaking them. Therefore, reproduction suffered greatly.

I’m glad their populations have recovered. It’s fun to watch them. These raptors can fly at speeds as fast as 80 miles per hour. They wait until all odds are in their favor. Then they do their thing.

Ospreys are efficient fishermen. Ask any aquaculture farmer and they will tell you that ospreys can steal profits in a hurry. Killing them isn’t an option as they are protected. Harassing them or interfering with their nests isn’t allowed either.

When ospreys catch fish, they position their prey facing forward for better aerodynamics. This is important as these birds carry large payloads for their size. Ospreys look larger, but adults only weigh about three pounds.

Ospreys nest in large elevated open places near water. They build structures bird watchers can monitor with ease. Both males and females help build nests from sticks. They line them with finer materials.

Parents use the same nests year after year and fortify them with more material. After several years these structures become massive. Sometimes nests are constructed at the tops of large dead trees, but utility poles and other man-made structures become the basic framework for many osprey nests.

Females usually lay three eggs which hatch in five to six weeks. Sometimes males help incubate them. Once the eggs hatch, males bring fish back to the nest. Young birds stay in the nest with their mother for about two months.

Older hatchlings usually bully the younger ones when food is scarce. Often, only the first hatched egg survives. Ospreys only hatch one brood per year, so a productive nesting site is critical for survival of the young. Ospreys are long-lived birds and usually breed for about ten years.

Osprey on a nest made on top of a utility pole in Down East Maine


Ted Manzer teaches agriculture at Northeastern High School (

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Oyster mushrooms are a common fungus on deciduous trees

A friend of mine brought in a mushroom sample recently for me to identify. I smiled when I saw it. When I was a teenager, it was one of my favorites to collect. My dad and I usually found it on dead or dying elm trees.

It’s called oyster mushroom (Pleurotus ostreastus) and it’s one of the most abundant in North America. These mushrooms are tree rotting fungi, but they don’t kill healthy trees. Usually trees are already stressed and dying before oyster mushroom spores invade them.

These fungi are saprophytic. That means they break down tissue that is already dead. Parasitic species attack living tissue.

I have been hesitant to write about collecting wild mushrooms for fear I might encourage someone to partake some without proper training. Many edible species are abundant, but so are many questionable ones. One mistake is all it takes to stumble into a disaster.

Even this oyster mushroom has one lookalike that could pose a problem for mycological newbies. It’s called the angel wing mushroom (Pleurocybella porrigens) and it grows strictly on pines and related conifers. Both these mushrooms have a clam-shell appearance. Angel wing fruiting bodies are white with a white spore print. Oyster mushrooms are cream colored to tan, also with a white spore print.

Angel wing fungi have much thinner flesh than oyster mushrooms do. They also have very little odor. Some mycologists describe oyster mushroom scent as anise-like. I think they have a seafood smell when raw. That’s why I always thought they were called oyster mushrooms. Most literature reports their overall physical appearance to be oyster-like, and that’s the reason for the name.

Oyster mushrooms and angel wing mushrooms both have what we call gills (lamellae) on their lower sides. Gills are parallel slits on the undersides of the fleshy caps. Both also don’t have a true stem-like structure called a stipe. Parallel gills run the entire length of the cap on both.

I like to collect oyster mushrooms for several reasons. Usually they can be found in great abundance. A bushel or more on a single tree is not uncommon. They have nice flavor and freeze and can well. I think they are too thick fleshed to make good drying mushrooms. My experience is that once dried they become leathery.

They are best if cooked. Raw ones are too chewy. I sauté them in butter or olive oil and season them with a little salt and garlic. According to many sources they are a rich source of antioxidants and even contain chemicals that reduce bad blood cholesterol. Research also indicates blood glucose levels can be reduced by this fungus.

Except for the angel wing mushroom, I can’t think of anything else that resembles oyster mushrooms. Oysters only grow on deciduous trees. Around here we find them mostly on beech, cottonwood and sweetgum. They are sometimes spotted on oak, hickory and other hardwoods.

As with any type of food, even if you trust the source don’t ever eat much the first time. Some people have no reaction while others could get quite sick. Mushrooms especially are nothing to play with. Always confirm the identification with an expert or maybe two.

Oyster mushrooms showing the upper and lower sides

A nice mess of oyster mushrooms

Oyster mushrooms on tree


Ted Manzer teaches agriculture at Northeastern High School.

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Grape Holly is a shrub with winter appeal

Recently, someone asked me about shrubs that were showy in winter. Obviously, camellias fit that bill as do winterberry holly and a few others. Mahonia, often known as grape holly, is an underused adaptable shrub that also has winter attributes.

I have one that is in full bloom right now. It has bright yellow flowers which will give way to purple grape-like fruits later. Broad, multibladed leaves are spiny and shiny. Cut off a twig and you will find the wood is yellow. That shouldn’t be a surprise as this is not a holly at all. It’s a member of the barberry family.

Barberries have yellow wood, not that it’s used for anything commercially. Several years ago, my daughter conducted a science project using natural plant dyes that could be collected in winter. Mahonia wood makes a beautiful colorfast yellow dye for fabric.

There are many species of Mahonia. The most common is Oregon grape holly, but numerous others are commercially available. One gaining popularity is called ‘Soft Caress’. It is a spineless cultivar that has a palm-like appearance. It also doesn’t get too tall, making it useful in more situations.

‘Wintersun’ and ‘Charity’ are taller cultivars that make great specimen plants. They usually attain heights of 10-15 feet. Yellow flowers adorn these plants from late fall to late winter.

These evergreen barberry cousins thrive in moist but well-drained soil. Soil pH is not very critical. Grape hollies also are best in partial sun but will tolerate substantial shade. One thing to consider is that they will bloom less in shadier locations.

Most literature list hardiness as zone seven or possibly six in sheltered locations. Some sources claim it to be hardy to 30 below (zone 4), but I think that’s pushing it.

I have one planted next to a loquat. The loquat was nearly totally killed by last winter’s extreme cold during the first week of January. The grape holly wasn’t hurt a bit.

Sometimes they are difficult to establish. However, once ensconced into their new home they require very little care. They aren’t heavy fertilizer users and they don’t require much pruning. However, plants can be encouraged to grow prostrate if taller canes are removed. In some situations, this can be effective.

Few diseases or insects attack Mahonias either. Deer usually leave them alone, but in winter if food sources are short, deer will nibble at them, especially the flowers.

Colorful fruits are edible but quite sour. With a generous influx of sugar, they do make a flavorful jelly or jam. Usually no pectin needs to be added as fruits are rich in it already.

Medicinally, grape holly is a major player. Stem and root tissues are used to treat stomach ulcers, acid reflux and other digestive system maladies. Herbalists prescribe topical formulations to combat psoriasis.

Grape holly also contains a chemical called berberine. This is often used to treat high blood sugar. Holistic practitioners also use berberine to combat high blood pressure. Those with low blood pressure or people with organ transplants should avoid it.

Close-up of Mahonia inflorescence. This specimen is in full sun and still doing well.

Ted Manzer teaches agriculture at Northeastern High School (

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Sweetfern is a spicy northern cousin

I was trimming a wax myrtle the other day when I caught a whiff of its sweet fragrance. It reminded me of my many treks through the Maine wild landscape. Walking through waist-high patches of sweetfern gave my clothes an aroma that lasted all day.

Sweetfern (Comptonia peregrina) is not actually a fern at all. It’s a flowering plant in the same family as wax myrtle, sweet gale and bayberry. Similarly, it can be used as a spice, too. This shrub has an even stronger taste and aroma than any of those. It also has the same insect repelling properties.

According to some sources, it can be found in our area, but I’ve never encountered it. I have seen it in a few open places in the mountains of western North Carolina though. However, it’s not a major species there either.

It’s a common staple to sunny waste places in northern regions of the US and is hardy as far north as central Canada. It also has a unique quality which enables it to thrive on infertile soils.

Like legumes, sweetfern can derive nitrogen directly from the atmosphere through bacteria that live on its roots. The bacteria can split nitrogen molecules and combine them with hydrogen to form ammonium compounds plants can use. In exchange for the nitrogen fertilizer, sweetfern roots provide sugar to the bacteria.

This relationship makes sweetfern a great conservation species. It quickly colonizes disturbed sites and thrives in full sun. Plants also form mats of underground stems that help keep soil from eroding. Sweetfern tolerates drought well, and this further enhances its conservation qualities.

While sweetfern is a flowering plant, the flowers are not showy. Separate male and female flowers are found on the same plant, and the tiny nutlets that form are edible and very palatable. I’d consider them survival food though. They’re good, but it would take considerable effort to procure enough to save for future use.

The fern-like foliage is the attractive feature for this species. Plants make a great naturalizing border in their native range. Here in eastern North Carolina we are probably a little too far south for this wax myrtle cousin to adapt. Plants are also deciduous, and many folks prefer most of their landscaping to be evergreen.

Foragers traveling to northern states or eastern Canadian provinces might wish to collect some foliage from this shrub. It makes a tasty tea and simmering potpourri. Herbalists prize sweetfern for medicinal use.

Wildlife utilize sweetfern for food and cover. Small birds and mammals make homes in its thick undergrowth. Several butterflies rely on its foliage to complete their life cycles. Deer and rabbits use sweetfern for winter browse. It’s not their favorite food, but it provides sustenance when food supplies are limited.

Sweetfern is the alternate host of the sweetfern blister rust disease caused by the fungus Cronartium comptoniae. This affects pine trees with needles in groups of two and three. This includes many of our native pines. White pine isn’t susceptible. Economic losses for the trees are small, even in sweetfern’s native range, but the disease could be a consideration for some wishing to establish sweetfern here.



Ted Manzer teaches agriculture at Northeastern High School.

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