Stewardship Outings Interns are out all year working hard in our parks and natural areas managing invasive weeds and protecting native plants and animals. See their featured invasive weed of the week and a native plant in danger.
Join us at an invasive weed removal day. Information at: http://sierraclub.org/maryland/invasive-species-corner
Featured Invasive Weed and Native Plant of the Week
Fall 2017 - entries submitted by Fiza Zahid Stewardship Intern
Summer 2016 - entries submitted by Nick Yoder (natives), Stewardship Outings Coordinator Intern and Zev Kaplowitz (invasives), Stewardship Outings Field Intern
9/15/2016
Non-Native Invasive; Mile-A-Minute Weed Persicaria perfoliata
Mile-A-Minute weeds are native to Asia and also known as Asiatic tearthumb. The plant was introduced in the U.S. in the 1930's accidently via a nursey stock. The plant resembles a vine, with triangle shaped leaves and distinctive circular strucutures called ocreae. Flowers and fruits grow from the ocreae. The fruit appears glossy, black/reddish and berry like. They grow very rapidly, growing up to 6 inches a day, causing the plant to grow over other vegetation and completely take over a certain area. The consequences of unchecked growth causes a decrease in native plants due to decreased photosynthesis. However, biological control has been introduced to help control the plant. A weevil, that only eats Mile-A-Minute, has been introduced to areas with this invasive plant. It is called Rhinoncomimus latipes. The result is that the plant's growth rate has decreased down to 3 inches per day and is still decreasing. Out in the field, holes are visible on the plant's leaves which indicate that there is biological control happening.
Photo on the left shows a plant covered in Mile-A-Minute at Magruder Park and the photo on the right is after removal.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
10/15/16
Non-Native Invasive; Japanese Stiltgrass Microstegium vimineum
Japanese Stiltgrass is native to India, Malaysia, China, Korea and Japan but has been introduced in the U.S. in the early 1900's. This plant likes to grow in a variety of habitats from woods to marshes and blooms in September to October. The average height of the plant is 2-3 feet, has a thin stem and a slight silver line running down its leaves. There are native plants that look similar to the invasive but the silver line is often used to distinguish between the two. The plant has spread across the east coast and is spreading west. Currently there are no known organisms that only eat this plant, so removal or herbicide is the best option at controlling the invasive plant. The roots are often not too deep, so it is easy to pull them out by hand. Stiltgrass with few to little native plants are easily visible and common. The Sierra Club stewardship interns have been working at many local parks over the summer and the fall to remove the plant.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
8/9/16
Non-Native Invasive; Garlic Mustard Alliaria petiolata
Garlic Mustard’s origins begin in Europe but were introduced into the United States in the mid - 19th century for nutritional and medicinal purposes. While it takes as long as two full years for this plant to mature and produce seeds, each Garlic Mustard plant can have nearly 20 seeds within its shell. This leads to an exponential growth pattern that can quickly drown out the rest of the natives in the area. While mainly situated amongst forest edges, Garlic Mustards have been found in pristine areas as well. Garlic Mustard’s flowers, which are found to be mainly white, blooms during April time but are died out come June. Researchers have found that Garlic Mustard is allelopathic (it releases chemicals that hinder growth of other plants). This has been proven through laboratory experiments at Michigan State University in 2008. Removing Garlic Mustard plants is as simple as pulling the loose weeds from the earth, but this needs to be done before they produce seed (June/July), or there is a likelihood of spreading the plant. There is no excessive strength or tools needed but be prepared to come across a lot of it.
Native; American holly, Ilex opaca
American holly is typically a medium-sized tree, normally growing to heights of 15 to 30 feet tall, but records indicate mature heights of up to 100 feet. Its leaves are evergreen and can be identified most easily by the sharp spikes or prickles around the margin of the leaf. The bark of it is smooth, and grayish to grayish-brown. The dense branches of this holly grow nearly horizontal in a spreading crown, which takes on a pyramidal silhouette. The American holly is dioecious, which means there are both male and females, and both must be planted in an area where berry production is desired, which is typical because the bright red berries provide winter interest. The berries are also an important source of nutrition, especially through the winter. After the plant has been established for several years, it produces small white flowers from April to June. It can grow in dry or moist soils, but grows slowly. It is a desireable and adaptable landscape plant, as outlined in this article. Additinally, this USDA fact sheet provides further detail on the basic character of this native plant. A note about identification; there are exotic hollies that also have spiked margins, but the pattern and amount is different than that of the American holly.
In relation to invasive species the American holly does a good job at mitigating invasions with its thick, evergreen leaves which in totality severely limit the amount of sunlight that can reach the forest floor. Often when we are walking through the woods surveying the spread of a plant like garlic mustard, there is no growth under the holly trees. This can be true with other natives as well, like beech for similar reasons, or some pines whose needle litter lowers the soil ph making it less habitable for some invasives species. As with many native plants there are often small holes in the leaves, evidence of insects eating the vegetation. The opposite is true with non-native invasive plants and animals, as they have no natural predators and can therefore spread without natural biological control.
The character and growth habit of the American holly make it a desirable tree in both wilderness and landscapes areas. Many cultivars are sold in nurseries in the area, but it is not very common to see the native holly for sale, in my experience. The difference in shape and density make this an unfortunate circumstance because the native holly is typically a more ...delicate… looking tree, especially when it is part of a forest understory. It does not dominate a garden for instance, as a thick evergreen blob, as indicated in the above photos of a two or three year old American holly I transplanted from a nearby forested area into my garden. The sparse, vertical branching is spaced evenly enough to see the curves of main trunk and the vertical spacing between limbs allows for glimpses through the tree to the background. These characteristics, along with the berries and evergreen leaves make it an extremely versatile plant, in my opinion. To learn more about the holly and efforts of those that support the American holly visit the American Holly Society website. As further demonstration of adaptable hollies are, this article from National Geographic talks about the spike on the holly leaf as a defense mechism for deer browsing.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
8/1/16
Non-Native Invasive: Amur “Bush” HoneySuckle Lonicera maackii
Of the four categorized Bush HoneySuckles identified within American forests and woods, the Amur Honeysuckle is most prominent on the Eastern half of the United States. Originally native to Asia, particularly Northern and Western China, this Bush HoneySuckle was introduced to the U.S. with good intentions to provide home and urban ornamentals as well as control erosion, create wildlife cover, and provide food sources. However, as most invasives are deceptive by nature, the Amur HoneySuckle proved to have aggressive growth patterns, forming dense leave clusters, blocking out sunlight to surrounding plants. In addition, these beasts can grow anywhere between 6 and 15 feet long. The Amur HoneySuckle can be identified by its unique white lobed/tubular flowers, lined and shredding bark, and hollow pitted stems. They grow in moist areas such as savannahs and grasslands, and thrive best in shaded areas.
To remove this invasive species, one must be prepared to do some intensive cutting or sawing. The trunks of these bushes can be extremely thick and the use of chainsaws might be required. Always remember that after having cut the stump as close to the root as possible, proper herbicide must be applied to prevent regeneration. In Prince George’s County alone, there are multiple parks and wildlife areas that are suffering from the inhabitant Amur HoneySuckle and proper measures must be carried out. Remember the reason for removing our local invasive species is to improve biodiversity, save native wildlife and keep our wild zones pristine!
Native; Staghorn Sumac, Rhus typhina
The staghorn sumac grows in shrub and small tree form, and is native to much of the Northeast United States, including Maryland. It is most easily recognized by the large, dark-red fruits that develop on the end of branches. They are soft, fuzzy fruits similar in character to the fruit of the common ‘cat-tail’. It has alternately, pinnately compound leaves, which means there are multiple leaves growing on the smaller stems (rachis) that branch off of the larger central stalk. The leaves show fantastic fall color, shining with shades of brilliant red, and dappled highlights of orange and yellow. As some of the first leaves to change color, they are harbingers of Autumn. An interesting note is that the fruits can be used to make lemonade! As it pertains to the role the staghorn sumac plays in our native ecosystem, they have high wildlife habitat value as outlined in this article by the NJ Audobon Society.
This image shows a recently fallen Staghorn Sumac, in Buck Lodge Community Park. What made this tree so special was that it had recently been identified by M-NCPPC Park Ranger Michael Ellis as the possible County and State Champion Staghorn Sumac. The designation of a champion by MD Big Trees means that it is the ‘largest’ tree of its species in the defined region. Though a large part of this calculation depends on the circumference of the main trunk measured at breast height (54”), it also includes measurements of the height and spread of the canopy, which are commonly gathered using laser rangefinders. The current Co-Champion sumac is 18 inches in diameter and 30 feet high, both measurements of which were ostensibly topped by the Buck Lodge Sumac. Unfortunately, a few weeks after beginning the process to have this tree registered as Champion, a series of large thunderstorms came through the area overnight and the tree couldn’t withstand the stress of the winds.
As a closing anecdote, this incident made a lasting impression on me. As it happened, a park patron had informed us that morning that a tree had fallen over the trail entrance on the other side of the park. As we drove over to assess the damage, we discussed the possibility of it being the sumac. I doubted it… did not even really consider it a possibility, in truth. What were the chances, i thought, of the one tree that we had special interest in of the thousands of trees in the park being the one tree that was felled by the storm?
But as we stood looking at the fallen almost-champion, I realized the error in my thinking. Of course it had fallen. After all, it had lived longer, perhaps, than any living staghorn sumac in the state. And this is what made it so special; it was old, and I was looking at the end of a singular story. It made me wonder where the next future fallen champion was emerging from the soil.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
7/25/16
Non-native invasive: Linden Viburnum , Viburnum dilatatum
Linden Viburnum is a deciduous shrub having round, dark green and often shiny leaves that additionally blooms white creamy flowers in the Spring months and red berries in the Fall. Linden, along with other Viburnums grow ideally in moist, fertile areas. While it’s seemingly appealing color, fruit, and nature made it a popular choice to introduce into America from Eastern Asia in the 1800’s, the plant has proved to be invasive in many ways. First, like many invasives, there is yet to be an identified wildlife species that finds nutritional value from the Viburnum leaves, making it a threat to biodiversity. More importantly however, is the sheer size and density that these shrubs can grow to, reaching nearly 10 feet in both height and width, shadowing and blocking sunlight to nearby plants, preventing much native growth and regeneration in surrounding areas. Removing is a relatively cumbersome process so the following steps should be taken:
Identify the Linden Viburnum by its brown, densely pubescent bark, and its dark, rounded, deeply veined leaves. Additionally, there are two small glands on the back, base of the many of its leaves (little dark spots) that will help prevent confusion with the native arrowwood viburnum, Viburnum dentatum.
Cut the shrub as near to the base of the plant as possible. Some linden viburnums can get fairly thick, so appropriate gear such as a proper cutting saw and gloves are helpful. Young plants can often be removed by hand pulling.
Remove the cut branch away from the area, prohibiting re-rooting
Treat the cut stump area with glyphosate or another type of herbicide
After removing the plant, try replacing them with some native plants offering similar foliage and flowering such as the common winterberry, the American beautyberry, or the red chokeberry. Michael Ellis, A vegetation management field coordinator and Prince George’s County park ranger says that the average population believed there was no such thing as a bad viburnum, but the invasive tendencies of the linden viburnum are proving that statement wrong.
Native: American Chestnut, Castanea dentata
The American Chestnut, in its natural form, is a large tree generally considered the finest chestnut species in the world owing to its quality of fruit for wildlife and wood for timber. It can be identified most easily by the shape of its leaf, which has ‘saw-toothed’ serrations on the leaf margins, and a leaf tip that comes to a long narrow point. The American chestnut’s native range stretches from the Northeast U.S to the South, generally around the appalachian mountains and foothills. The tree was important to wildlife because of the high nutritional value of the nuts and the leaves; a beneficial relationship that regional wildlife and the Chestnut depended on for years.
Over the past century, however, the vast majority of American Chestnuts have been killed by an invasive pathogen, the chestnut blight fungus (small tree in the image on the right). Discovered in 1904 and determined to have been brought to the United States in woodstock of other trees imported from China, it is estimated that 4 billion American Chestnuts have been killed.
In fact, in the local parks where the Stewardship team has been working this summer to remove invasive species like the linden viburnum, we look for remnants of the American Chestnuts that have survived by spotting relatively thin, dead trees about twenty feet tall, which also have new succors coming up from the base of the plant. Unfortunately, this is the typical condition we find American Chestnuts in because the chestnut blight basically destroys everything of the plant that is above the ground, while leaving the root systems intact. So, of the plants that do survive the devastating stress of being infected with the blight, it is rare to find mature plants of any significant size. In all of our work this summer, we have not seen an American Chestnut that has been unaffected by the blight, despite our being in the prime habitat for the species to thrive.
The largest example of the species in Maryland is in Montgomery County and measures 4'6" in diameter, which is decidedly thin for a Champion large shade tree. There are significant efforts underway to regenerate and reestablish the American Chestnut. You can read about the efforts of The Amercan Chestnut Foundation, one of the leaders in this arena @ http://www.acf.org/mission_history.php. They have been working to develop a blight resistant hybrid, and have some promising ongoing research. This article from 2006 discusses some of those efforts, and demonstrates the onging struggle and required vigilance to protect native plants.
Sources;
https://en.wikipedia.org/wiki/American_chestnut
http://www.acf.org/partnerships_in_action.php
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
7/18/16
Non-native Invasive: Wavy Leaf Basketgrass, Oplismenus undulatafolia
Wavy Leaf Basketgrass is a perennial grass with flat, dark green leaves having the property of rippling waves along the blade. Originating from areas of Europe and Asia, It was first introduced to the U.S right here in the state of Maryland amongst the forestry of Patapsco State Park in Howard county in 1996. Since then, it has spread like wildfire all the way down to areas of mid-Virginia carpeting the floor of many wildlife areas. Because of it’s low growing positions near the slopes of trees, the Wavy Leaf prevents regeneration of native hardwood tree species causing disaster for deciduous forests. Moreover, its stealthy growing habits make early prevention a priority. Wavy Leaf has sticky awn on the seeds, attaching itself to passing animals causing further spread. While a traditional herbicide application can be effective for large patches of this species, the following steps should be followed in order to hand pull the weeds from their root.
Identify the Wavy Leaf Basketgrass by its standard location (noted above) and how it looks (description above, picture below)
Carefully, follow the thin roots down to the earth, identifying its source of growth
Very gently, pull the root to reveal more vines, and repeat this step until it is all above the dirt
Slowly pull all the roots from the ground until plant is detached
Store the Wavy Leaf above ground on either a log or a tree branch in order that it does not have contact with the earth
It is critical that Wavy Leaf is recognized and dealt with early on, more details on the plant are available here. You can Help map the spread of invasives species in the region by using the Mid Atlantic Early Detection Network (MAEDN) smartphone app. and mapping program. In that regard, Towson University is working on a mapping project, as well, under the guidance of Vanessa Beauchamp.
Native: Christmas Fern, Polystichum acrostichoides
The christmas fern is a perennial evergreen plant native to Maryland, and much of North America. It prefers to grow in moist, shaded areas in the forest, often part of a community of other fern species. The Christmas fern, is popular in cultivation as an ornamental plant for gardens and natural landscaping, because it is easy to grow and can be used in many settings and soils. Because it's evergreen, Christmas fern is often used in winter gardens. It has been noted that this fern can serve a soil conservation and erosion control function on steep slopes. The fronds are semi-erect until the first hard frost, after which they recline to be flat on the ground, effectively holding in place fallen leaves so that they become soil on the slope. Christmas fern got its name because it stays green through the holiday season. It is a robust, leathery fern which has glossy, green fronds year-round.
The Christmas fern can be most easily identified by the alternate leaf arrangement combined with the oblong shape of the base of the leaflets. It is categorized as a ‘once cut’ fern, as opposed to twice, or thrice cut ferns, which is a common way of identifying native ferns. Another good identifying feature is whether the leaves taper toward the base of the plant stalk, or remain broad. The Maryland Native Plant Society provides an identification key that is very helpful in the process.
As it relates to the non-native invasive of the week, Wavy Leaf Basketgrass, unfortunately, the same microclimates that allow for successful native fern establishment, regeneration, and growth are the prefered habitat for Wavy Leaf. Furthermore, the additional shade provided by the fern canopy adds more cover to the forest floor, leading to retention and presence of more moisture, moderate temperatures, and overall better conditions for the establishment of unnoticed populations of Wavy Leaf, as well. When surveying for Wavy Leaf in the field, we often look for low lying areas of ferns near streams.
The fern ecosystems that are threatened by wavyleaf, like the above photograph near the liberty resevoir in Carroll County, are some of the most visually striking ecosystems in the region and are important for providing cover to ground dwelling birds, small mammals, and other wildlife, especially in the wintertime. You can help us protect these and other vital habitats by volunteering for one of our invasive weed removal outings.
Sources
http://www.wildflower.org/plants/result.php?id_plant=POAC4
https://en.wikipedia.org/wiki/Polystichum_acrostichoides
Photographs by Zev Kaplowitz and Nick Yoder
<br>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Invasive and Native of the Week;
7/8/16
Non-native Invasive: Japanese Wisteria, Wisteria floribunda
Japanese Wisteria is a woody ornamental vine that grows egg-shaped wavy leaves and blooms beautiful violet-blue flowers around the Month of April. These aesthetic features give reason for the introduction of this ornamental into the U.S from Japan in 1830 as a decorator for lawns or backyards. However, with the Japanese Wisteria invading our wild habitats for nearly 200 years now, the plant has shown its destructive habits. The hard vines twine counter-clockwise up host tree bark, choking and killing them while simultaneously blocking smaller natural vegetation from sunlight with its dense thickets. It quickly overcrowds and overthrows the needed diversity in these areas and thus disrupts natural wildlife and plant community development. Michael Ellis, A vegetation management field coordinator and Prince George’s County park ranger, has been working with Wisteria for 10 years now and comments on it’s horrible effects in Magruder Park, Little Paint Branch Park, and Buck Lodge, as well as others outside the county. He states that the “Wisteria’s favorite variable is time” and that action needs to be taken immediately. To remove the Japanese Wisteria the following steps should be followed:
Recognize and identify the leaf and/or vine of the Japanese Wisteria (see above)
Use a saw, lopper, or shears to cut the vine at the root as close to the ground as possible
Treat the cut area with Glyphosate or another effective herbicide
Cut hanging vine down from as high as you can reach
Please help prevent the hysteria of Wisteria in Maryland's natural parks in order to protect our wildlife and please be wary of buying Wisteria seedlings next time you're at your local nursery.
Unmanaged Wisteria Treated Japanese Wisteria Wisteria curtain
Native: Mountain Laurel, Kalmia latifolia
The native mountain laurel most commonly grows in shrub form (3-20ft), but can occasionally grow as a tree. It flowers in late spring, pale-pink and white, and has evergreen foliage that shines in the winter sun. It often forms large communities, and when it gets old, it has an open sprawling habit with a peeling strip cinnamon colored bark. It typically lives in acidic soil and will tolerate very dry conditions. An interesting characteristic is the unique way it dispenses pollen. As the flower grows, the filaments on which the pollen develops build tension. Once the flower opens enough to receive a landing insect the filaments will ‘spring’ closed, effectively splashing the bee in pollen to hasten the process of transference.
Historically, American Indians used leaf tea from the Mountain Laurel as an external wash for pain, rheumatism, in liniments for vermin. Historically, herbalists used minute doses to treat syphilis, fever, jaundice, heart conditions, neuralgia, and inflammation. The roots were used by Native Americans to make spoons, giving it one of its names- Spoonwood. The juice of the plant or a decoction of the leaves is believed to have been used by Native Americans to commit suicide. State flower of Pennsylvania and Connecticut.
In Bucklodge Park (below) and other forested areas where these two plants grow alongside each other the overwhelming density of the wisteria is killing mature Mountain Laurels as well as preventing regeneration by smothering or outcompeting the native saplings.
Sources:
past.http://herbs-treatandtaste.blogspot.com/2012/07/mountain-laurel-native-to-usahealth.html
http://www.mdflora.org/Resources/Publications/Marilandica/marilandica_v4n1.pdf
Photots, MD Sierra Club