Monthly Archives: June 2019

What is an Invasive Plant?

Ivy 3aI once was quite proud of the English Ivy tree I’d nurtured in my townhouse garden. I was ignorant of its impact on the environment.

My mother and I had planted a pair of four-inch plants some 20 years before I started shaping them into a tree. I didn’t know that English Ivy was invasive. I knew very little about invasive plants.

That changed when I became a Green Spring Extension Master Gardener in 2014. I learned that invasive plants are a species accidentally or intentionally introduced by humans into a region where those plants did not originate. They can cause great damage to the new area’s natural resources. An invasive species can be any kind of living organism – plant, insect, fish, fungus, bacteria and even seeds or eggs. Species that grow and reproduce quickly and that spread aggressively can be labeled ‘invasive’.

Ivy 1aThe Virginia Department of Conservation and Recreation (DCR) has created an Invasiveness ranking that categorizes the level of threats to forests and other natural communities and native species from invasive plants. The categories are high, medium and low. Kevin Hefferman, a stewardship biologist at DCR, says the ranking increases for species that:

• Alter natural processes, such as water flow or soil chemistry
• Invade undisturbed natural areas
• Cause substantial impacts on rare or vulnerable native species or natural areas
• Are widely distributed and generally abundant where present
• Disperse readily to new places
• Require significant resources to manage and control

Naturalists encourage gardeners to curb the spread of invasive species by planting native plants and removing invasive ones. There are many web sites that offer native alternatives, including those of the Virginia Native Plant Society, The Master Gardeners of Northern Virginia, and Green Spring Gardens. More information also is available from Master Gardeners at Green Spring.

Ivy 4In full disclosure, I adore English Ivy (Hedera helix). However, I won’t plant it. It’s an evergreen, perennial vine. It grows as a dense ground cover (juvenile stage) and a climbing vine (adult stage). Regretfully, its dense foliage blocks sunlight and restricts growth of other plants. As pretty as it looks growing up mature trees, its heavy vines loosen bark and hold moisture against the trunk, often causing fungal disease and death. Heavy vines also can fell trees in bad weather. English Ivy also nurtures bacterial leaf spot, a disease seen in elms, oaks and maples. It spreads by seeds and runners. Mature vines produce flowers and seeds that birds enjoy and spread. It is also known to cause wildfires to spread as flames climb vine-covered trees. It tends to climb anything it can use for support such as fences, homes or trees.

Invasive species overtake native species and destroy ecosystems that rely upon diversity of species to survive. They often provide little or no food value for wildlife. Kudzu is another devastating invasive plant that grows at a rate of one foot per day with mature vines as long as 100 feet. It engulfs everything in its path from trees to shrubs to homes and cars.

When visiting a plant nursery or accepting plants from friends and neighbors, avoid invasive species. Plant natives for their beauty and for the well-being of the environment.

Author Gioia Caiola Forman is a Green Spring Extension Master Gardener and a board member of the Friends of Green Spring.

The Life and Times of the Manassas Gap Railroad

Manassas Gap Railroad

These stone walls are remnants of the earthworks built to carry the rails of the Manassas Gap Railroad’s Independent Line, begun during the railroad boom before the Civil War and never completed.

Weaving through Alexandria, Fairfax City and on to Manassas is the abandoned railway bed of the Manassas Gap Railroad chartered in the mid-19th century. Today these bulwarks of dirt curling west to the Blue Ridge Mountains are silent witnesses to ambitious dreams, changing economic and political climates, and the devastating ruin caused by the Civil War. Two of the best spots to explore these beds are on parkland at the Manassas Gap Railroad Historic Site in Annandale and Hidden Oaks Nature Center. They’re just a couple blocks apart on Royce Street in Annandale.

The railroad was built in part as a product of the speculative frenzy of railroad building in the late 1840s and early 1850s. The advent of steam-powered engines ignited the construction of railroads to connect the fertile farms of the expanding West to the traditional markets and business hubs along the East Coast. A feverish program of railroad construction created some 3,668 miles of track in less than 20 years.

Economic competition for access to the productive farms of the Shenandoah Valley increased when the Baltimore and Ohio Railroad (B&O) opened a line to Winchester through Harper’s Ferry in 1836. The merchants of Alexandria, fearful that they were losing their crucial wagon trade with the Shenandoah Valley, received a charter in 1848 from the state legislature for the Orange and Alexandria Railroad (O&A). The line ran from the rural fields south in Orange to the port city.

Its success bred greater ambition. By 1850, another group of merchants and farmers received incorporation for the Manassas Gap Railroad (MGRR) that would recapture the wheat trade of the upper Shenandoah Valley that the B&O had successfully acquired through its Winchester branch. Wealthy planters and prominent business owners in the area determined its route and invested heavily in its future.

To reach the valley, the line would run west from the Manassas Junction on the Orange and Alexandria line, through Gainesville, past Front Royal, through the Manassas Gap and on to Strasburg. It was completed in three years and celebrated with rhetorical gusto.

Buoyed by new revenues and awash in plans for expansion, the MGRR company decided to build its own Independent Line directly from Manassas Junction to Alexandria rather than pay the O&A its high rail rental charges for goods that had to be transferred from the MGRR and shipped to Alexandria on those lines. The legislature approved the plan in March 1853.

The Independent Line was to run 34 miles, crossing the Bull Run west of Chantilly and then Cub Run, into a sweeping curve crossing first the Warrenton Turnpike and then the Little River Turnpike to what is now the city of Fairfax. It then ran east near the village of Annandale, turning south to re-cross Little River Turnpike, run through Indian Run Valley and on to just outside Alexandria.

The process of obtaining the necessary land, however, and the costs of the major filling and leveling required for construction reduced profits and assurances of state aid. By 1858, the company’s debts were enormous, and growing hostilities and talk of secession weighed heavily on the plan. One year short of completion, the Independent Line fell victim to the Civil War, and no steel rails were ever laid. Instead, its earthworks served as battle sites and as little-known transportation routes for both Confederate and Union soldiers.

The Manassas Gap Railroad never recovered from the war, during which its rails were torn up and its rolling stock destroyed by both sides. The right-of-way was relinquished, and much land was returned to farming. In some places, however, where there were deep cuts, high fills or substantial masonry work such as at Hidden Oaks and the Manassas Gap Railroad Historic Site in Annandale, the roadbed remains. Its high fill areas, shallow cuts and two historic culverts, all constructed during the 1850s, remain in remarkably complete condition. The Historic Site is a perfect place to look back on the complex tapestry of how people, places and events — especially surrounding the Civil War — converged to create a place of historic significance.

Author Jane Scully is a former ResOURces newsletter editor for the Fairfax County Park Authority.

Hidden Oaks celebrates its 50th anniversary in October. Interpretation of the railroad bed will be part of projects being developed for the celebration.