Thursday, March 28, 2024

Spring Invasive - Lesser Celandine - A Springtime Menace


As the winter chill begins to thaw and the first signs of spring emerge, one of spring's ephemeral flowers makes its debut: the lesser celandine (Ficaria verna previously Ranunculus ficaria L.). Often heralded as a harbinger of spring, this petite yet vibrant plant holds a unfavorable place in the hearts of nature enthusiasts and gardeners alike. 

Botanical Characteristics: 

Belonging to the buttercup family (Ranunculaceae), lesser celandine is a low-growing perennial herb native to Europe, western Asia, and northern Africa. It typically blooms from March to May, carpeting woodland floors, meadows, and riverbanks with a burst of golden-yellow blossoms. Each flower consists of eight to twelve glossy petals surrounding a bright yellow center, creating a striking contrast against the lush green foliage. 



Lesser Celandine, a.k.a. Fig buttercup (Photo: David Nicholls, NatureSpot.org National Biodiversity Network Trust [NBN Trust], UK)

Map of Lesser Celandine’s invasive range in the United States and Canada

Source: https://plants.usda.gov/core/profile?symbol=RAFI


Ecological Impacts: 

Despite its delicate appearance, lesser celandine plays a crucial role in undermining biodiversity. In its introduced range, it arrives very early in the spring, this gives the invasive plant an advantage over native ephemerals such as mayapple or Dutchman’s breeches that are still mostly dormant in those temperatures.  It spreads out over the ground, creating a thick carpet, making it virtually impossible for native understory plants to grow and survive.  Native wildflowers and pollinators are particularly negatively impacted by this invasive specieshroughout history, lesser celandine has been intertwined with various cultural beliefs and folklore. 

Cultural and Folklore Significance

In ancient Greece, it was associated with the god of love, Eros, and was believed to have the power to attract affection. In Celtic mythology, it was considered a symbol of regeneration and renewal, often appearing in springtime celebrations. In Christian tradition, the lesser celandine is sometimes known as “pilewort” due to its traditional use in treating piles or hemorrhoids. Legend has it that the plant’s knobby tubers, resembling piles, were thought to possess healing properties. 

Garden Cultivation and Management: 

Gardeners should avoid incorporating lesser celandine into their landscapes, because of its vigorous growth habit.  Controlling lesser celandine can be challenging due to its ability to spread rapidly. Here are some methods to control it:
  • Hand-pulling: Remove lesser celandine by hand, making sure to remove the entire plant including the tubers. This is most effective when the soil is moist, making it easier to pull out the roots.
  • Mulching: Apply a thick layer of mulch, such as wood chips or straw, to smother lesser celandine and prevent it from receiving sunlight.
  • Herbicides: Selective herbicides containing glyphosate or triclopyr can be effective in controlling lesser celandine. Always follow the manufacturer's instructions carefully when using herbicides.
  • Repeat treatments: Since lesser celandine can regrow from small root fragments, it may be necessary to repeat treatments multiple times to completely eradicate it.
  • Plant competition: Planting competitive native species in the area can help suppress the growth of lesser Celandine.

Remember to combine methods for the most effective control of lesser celandine, and be persistent in your efforts to prevent its spread.

Despite its allure, it’s important to exercise caution and not introduce lesser celandine to a garden setting. In New Jersey, where it is not native, the plant can become invasive, outcompeting native species and disrupting delicate ecosystems. Therefore, it’s crucial to consider alternative native plants that offer similar benefits without posing a threat to the environment. 

Additional Information






 

Tuesday, March 26, 2024

Spring Weeds: Deadnettle and Henbit. What's the difference?

Its spring and spring plants are beginning to flower.  Have you ever notice the little purple/pink flowering plants that appear in your gardener on your walks? They are probably two of the most common spring weeds found in gardens: deadnettle or henbit.  How can you tell them apart?

Deadnettle or purple deadnettle and henbit are often mistaken for each other.  Once you know what to look for they are easy to differentiate.  First some background.  In some of the literature you will see these plants referred to as purple deadnettle(Lamium purpureum) and henbit deadnettle (Lamium amplexicaule).  Unlike some other nettles, these deadnettles do not sting.  In other words it is a "dead" nettle.  The common name henbit comes from observations that chickens like to eat it.

Deadnettle and henbit are winter annuals.  Both plants germinate in the fall and resume growth in the spring as the temperature rises, they set seed and then die in the late spring or early summer.

Square (quadrangular) stems

Purple deadnettle and henbit are members of the Laminaceae (also Labiatae) mint family.  There are over 250 genera of mints and approximately 7000 species.  Mints range in size from small herbaceous plants like henbit and purple deadnettle to trees.  There are certain characteristics that are common to all mints:
  • Square stems
  • Opposite, fragrant leaves
  • Bilabiate flowers 
  • Flowers ovary is segmented in four lobes
Purple deadnettle (on the left) and henbit (on the right) have square stems which are a common identification characteristic of members of the mint family.

Henbit - Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension

Henbit (Lamium amplexicaule)
Lamium amplexicaule L. - henbit deadnettle - Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 121. Provided by Kentucky Native Plant Society. Scanned By Omnitek Inc.- USDA Image Library





















Henbit has petioles on the lower leaves but not the upper leaves.  The upper leaves are clasping, hence 
the species name amplexicaule which means clasping.


Deadnettle - Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension

Deadnettle (Lamium purpureum)
Lamium purpurem L. - purple deadnettle - Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 3: 121. Provided by Kentucky Native Plant Society. Scanned By Omnitek Inc. - USDA Imahe Library

The leaves on deadnettle all have petioles.  The length of the petioles tend to get smaller as you move upward on the plant.  The upper leaves on henbit do have petioles and leaves on the lower portion of the plant have long petioles.



Deadnettle (on the right)  and Henbit (on the left) Leaves

Notice that the leaves on the deadnettle are more triangular in shape and not as deeply lobed as the leaves on the henbit.  The leaves of henbit have a more rounded shape, are deeply veined and have hairs on the upper and lower surfaces.

Visit the weed control links listed below for information on controlling these weeds around the home or in the lawn.

NOTE: Always read and follow herbicide directions carefully. Do not use herbicides for controlling broadleaf weeds in turf such as dandelion in or near ornamental planting beds. If weeds are a persistent problem in landscape planting beds homeowners may wish to consult with a professional landscape contractor. 

Additional Information

New Jersey Weed Gallery - Rutgers NJAES Cooperative Extension

Weed Control in Home Lawns - Rutgers NJAES Cooperative Extension

Weed Control around the Home Grounds - Rutgers Cooperative Extension


Monday, March 11, 2024

What’s Not to Like About Lichens?

Often overlooked, Lichens serve many functions in the natural environment. Not only are they good indicators of environmental health, but they also support wildlife. Known as a “keystone” species, lichens are vital to the well-being of the entire ecosystem. Late winter/early spring is a great time to take a walk and keep an eye out for the many different types growing in New Jersey.

Lichens come in different shapes, sizes, and colors.
Photo Credit: Alyson Ricketts, Rutgers Master Gardener of Burlington County

Lichens can be found growing on trees, rocks, soil, metal, plastic, cloth, etc. They are living organisms that function as a symbiotic combination of fungus, algae, and yeast. The algae provides nutrients through photosynthesis, the fungi protects the algae from drying out, and the yeast allows the lichen to produce an acid that protects it from microbes.

Lichens can be beautiful and take on many shapes depending on the type. The three main groups of lichens include: crustose (crusty), foliose (leafy), and fruticose (bearded or tubular).

Perhaps the biggest reason for lichens’ likability is that lichens are indicators of good air quality. They are used as bio-monitors and give scientists clues about environmental pollution levels. Most lichens will not tolerate air pollution, they require clean air. They may die if exposed to elevated levels of sulfur or heavy metals. According to the National Park Service, Lichen trap particulate matter in the air like dust, while also absorbing smaller pollutants like sulfur, mercury, and nitrogen. This means cleaner, healthier air for us to breathe.” 

In 2015, two species of lichens were removed from the Rutgers Pinelands Field Station and moved to the New York Botanical Garden in New York City. But, more than two years after the move, the lichens met their demise. Researchers attributed their non-survival to both disturbance and exposure to higher levels of air pollution than was present in their previous habitat in southern New Jersey.

Group of boulders with crustose lichens.
Photo Credit: Karen Dillman, U.S. Forest Service.

Contrary to a popular misconception, lichens do not harm trees. They do not feed on tree bark. Lichens are not a sign that a tree is damaged, dying, or diseased. They are found, however, on slow-growing, often mature trees. In this way, they can be an indicator of declining health of the tree because the bark has become brittle and cracked or the tree has defoliated. The lichens are not damaging the tree, simply using the bark as a place to exist and collect sunlight.

Foliose type lichen growing on a pine tree.
Photo Credit: Alyson Ricketts Rutgers Master Gardener of Burlington County

Fun Facts about Lichen:

  • Lichens occur in all habitats, including arctic, rainforests and desert.
  • Ruby-Throated Hummingbirds use lichen to line their nests.
  • Lacewing insects carry lichen on their backs as camouflage.
  • Lichens are a food source for deer, birds, and rodents.
  • Scientists can use certain slow-growing lichens to estimate the age of rocks, glacial retreats, and landslides.
  • Humans throughout history have used lichens in food, to dye clothing, and as medicine.
  • Some lichens can live for centuries.
  • There are approximately 3,600 species of known lichen in North America.

The next time you are out for a walk, take a moment to notice the abundant and different types of lichens.  Now you know more about them, you may find yourself breathing a bit easier and liking lichens a bit more.


 References and Additional Resources:

Rutgers Cooperative Extension Fact Sheet: “Tree-Dwelling Lichen”
https://njaes.rutgers.edu/fs1205/

University of Maryland Extension: “Lichen, Algae, and Moss on Trees”
https://extension.umd.edu/resource/lichen-algae-and-moss-trees/

US Forest Service: “Lichen Biology”
https://www.fs.usda.gov/wildflowers/beauty/lichens/biology.shtml

Us National Park Service: “Lichen-The Little Things that Matter”
https://www.nps.gov/articles/lichen-and-our-air.htm

New York State Parks Blog: “Likin’ the Lichens in New York State”
https://nystateparks.blog/2017/05/09/likin-the-lichens-in-new-york-state/

New York Botanical Garden Blog: “New Jersey Lichens Give Up the Ghost”
https://www.nybg.org/blogs/science-talk/2018/01/new-jersey-lichens-give-ghost/