Fluvanna Master Gardeners

Educating the Fluvanna County community to use environmentally sound and sustainable horticulture practices.

Invasive Plants

Invasive Plants

18 February 2008

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Invasive nonnative plants are the subject of a considerable amount of attention and debate and stories about invasive plants are now common in the popular media. As purchasers of non-indigenous plants that have the potential to invade natural areas, consumers are links in the distribution chain of invasive plants. Other links are those who import, propagate, transport, and sell non-indigenous plants. Ultimately, the result is a potential impact on our natural environment.

An Ailanthus tree.An Ailanthus tree.

A review of catalogs from U.S. wholesale growers shows that at least 50 percent of woody plant species are native to regions outside of North America. If one were to consider the species sold in any one area, the proportion of nonnative plants (not native to that particular ecosystem) would certainly be much higher. Most non-indigenous species have graced our landscapes with beauty and untold beneficial environmental effects. However, a significant proportion of these are invasive. Data from six nongovernmental organizations indicated that 34 percent to 83 percent of the total number of invasive taxa (species, varieties, or cultivars) in the U.S. had a horticultural origin.

One of the most lucrative areas of ornamental plant sales is the introduction of new-to-the-trade plants. These novel introductions fuel plant sales, stimulate efforts to seek out new introductions, many from outside the U.S., and yield substantial profits. A quick glance at most garden catalogs and mail order websites verifies this trend, a trend that encourages plant exploration and has the potential to exacerbate the invasive plant problem.

Environmental groups, regulatory entities, and those in the ornamental horticulture industry (including consumers) are the key stakeholders in the invasive ornamental plant arena. The different interests of key stakeholders can lead to conflicting viewpoints that may constitute standoffs without an apparent or imminent compromise. The perspective of an environmentalist is that nonnative invasive species represent a threat to nature. To ornamental industry personnel, profits and jobs are potentially threatened without the import and sale of these nonnative plants. As a result, the invasive nonnative plant topic evokes emotional as well as scientific or quasi-scientific debates. The lack of a complete understanding of invasion biology terminology and concepts is a significant impediment to meaningful dialogue and the resolution of differences.

What is an invasive plant?

The legal definition of an invasive species, and the official position of the U.S. government, is An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health. (http://www.invasivespeciesinfo.gov/laws/execorder.shtml) The legal definition of alien species, also termed non-indigenous or exotic, is with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem. In a strict interpretation, any plant outside its native ecosystem is considered non-indigenous. For example, black locust (Robinia pseudoacacia) is a common tree native to the central Appalachian and Ozark Mountains but is considered an invasive species in California. Thus, plants native to one state can be invasive in another state.

Predicting invasive potential

Predicting which non-indigenous plant species will become invasive is one approach to keeping potentially invasive species out of commerce, thereby eliminating the threat to the native environments. However, predicting which species will be invasive in a particular area is a very difficult task due to the complexity of nature. There has been an abundance of work to determine the plant characteristics and ecological factors that lead to plant invasion. At present, the most reliable and powerful predictor of a species invasiveness is its record of invasiveness in other nonnative sites. Many prediction schemes have been developed to assess the potential of plant taxa to be invasive. These approaches to understanding the invasive potential have significantly increased the ability to predict which taxa will be invasive.

Why should we be concerned about invasive plants?

In short, nonnative invasive plants have negative effects on biodiversity (i.e., the rich genetic resource of flora, fauna, and microbes) at the ecosystem level and the community and population levels. Examples of how invasive plants threaten the health of natural areas are 1) replacement of diverse systems with single stands of nonnative species, 2) changes in soil chemistry, land form processes, fire regime, and hydrology, 3) competition with endangered species, and 4) competition with and displacement of native fauna.

What can landscape professionals and gardeners do?

Information on the Internet can be overwhelming, confusing, and inconsistent. There are a few good sites that include ranking systems of invasive impacts based on scientific observation. NatureServe, a nonprofit conservation organization, has a current data-based assessment of non-indigenous plant species (http://www.natureserve.org/explorer/servlet/Natur eServe?init=Species). Other sources that have developed rankings relevant to Virginia residents are the Virginia Native Plant Society in conjunction with the Virginia Department of Conservation and Recreation (http://www.dcr.virginia.gov/natural_heritage/invsppdflist.shtml) and the SoutheastExotic Pest Plant Council (http://www.se-eppc.org/). These groups have ranked species according to their perceived and observed threats to the environment.

Finally, if a gardener would like to use a native plant as an alternative for a specific nonnative plant, there are books and websites that have this information (e.g., Native Alternatives to Invasive Plants, Brooklyn Botanical Garden, 2006; http://www.dcr.virginia.gov/natural_heritage/nativeplants.shtml [click on Native Plant Tables]; http://www.mdflora.org/publications/invasives.htm).

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For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.

Garden Safety

Garden Safety

11 February 2008

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Most homeowners use lawn mowers and string trimmers to maintain their landscapes. Some are gasoline powered, but others are electrical. Electrical tools used outdoors can be extremely dangerous if not handled with care and under the right operating conditions. Following are some general safety points for using electrical equipment:

A lawn mower.A lawn mower.
  • Never use electrical equipment when it is raining outside.
  • If the area where you are working outside is still wet from a prior rain, wear rubber-soled boots to provide some protection against shock or slipping.
  • In general, when using a mower or a string trimmer, wear long trousers to protect your legs from stones or sticks and wear shoes or boots with protected toe caps, such as steel-toe boots. Always wear approved, comfortable safety goggles to protect your eyes from flying debris.
  • When using an electric lawn mower or string trimmer, always keep the electrical cord behind you. Trail it over your shoulder or hold a short loop in your hand. Also, be sure to always cut away from, not toward, the electrical cord.
  • When using electric hedge trimmers, keep both hands on the handles. Also, be aware that the farther the trimmers are away from your body, the less control you have. Don't strain yourself -- rest your arms when they start to tire.
  • Children and pets can be a distraction, so be especially careful when using electrical equipment when they are in your work area, or better yet, keep them out of the area completely while you are working. A child can trip over or move an electrical cord, with disastrous consequences.
  • If the machine you are using stops because of an obstruction or electrical failure, unplug the machine before you start to check it or attempt to remove any obstruction.

Always follow any precautions and guidelines given on the electrical equipment you buy. You may also want to talk with a person experienced in the work you are going to do to see what you will need to make your gardening task safer and easier.

If you would like more information about safety you might consider attending the Albemarle County Farm and Family Safety Day on Tuesday, February 26 at Virginia Tractor, 2415 Ivy Road, west of Charlottesville from 9am to noon.  This event will offer safety demonstrations on tractor safety, chain saw and trimmer safety, lawn mower safety, trailer safety, and ATV safety.  In addition, many of our local agencies will be on hand to answer questions and offer advice.  Please R.S.V.P. by February 21 to Christine at (434)977-8100.

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For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.

Tree Stewards

Tree Stewards

4 February 2008

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Help fill our street with shady characters. Think canopy, that green leafy inviting kind that majestic, shade trees provide for our outdoor places. American author, Stephen Vincent Benet, said, The trees on the street are old trees used to living with people. Family trees that remember your grandfathers name. Today more than three-quarters of Americans now live in populated areas. Experts have estimate that for every four trees that are removed on city streets one tree is planted.

A tree puzzle.A tree puzzle.

But who cares for these friends of the family? Even city residents, often with the best of intentions, simply do not understand the special care needed for cityscape trees. With city parks and recreation budgets always in short supply, neglect is the major disease of community plantings and landscape trees. City trees survive under almost insurmountable odds, not the least of which include limited space for root growth, poor soil, water contamination from road salt, air pollution, and damage from pedestrians and vehicles.

Tree stewards are trained volunteers who work to preserve the trees that maybe were planted by even your grandfather. Whenever possible they help to replant and care for new trees to maintain the canopy of city streets for future generations. Tree stewards also teach others about importance of urban forests in their communities through educational programs like the upcoming Tree Steward Training Course being coordinated by the Charlottesville Albemarle Tree Stewards that I announced a few weeks ago in my Sunday article, Educational Gardening Opportunities.

Why not consider becoming a Tree Steward now and set aside your Monday mornings for this comprehensive 42 hour educational offering. Course presenters, serving in a volunteer capacity, will cover topics including all aspects of tree care and urban forestry. The professional affiliations represented by the course presenters include: Virginia Department of Forestry, Virginia Tech, Blue Ridge Community College, the Thomas Jefferson Center for Historical Plants, the Thomas Jefferson Soil and Water Conservation District, Greenways and Utility Foresters from Albemarle County and Appalachian Power, Montpelier, James Madisons home, Arboristry Associates, Ian Robertson Ltd., and Bartlett Tree Experts.

The deadline for registration is 15 February for the course which will run from 25 February 14 May. The Virginia Department of Forestry will be hosting the course at its woodland, campus state-headquarters, located south of Charlottesville in the Fontaine Research Park.

Upon completion of these instructional sessions, in order to become a certified tree steward, all trainees will also be required to serve a minimum of 40 additional hours on area Charlottesville Albemarle Tree Steward activities. Maintenance of tree steward certification is contingent upon a minimum commitment of 20 hours of tree steward volunteer service per year.

The Charlottesville Albemarle Tree Stewards and the Virginia Cooperative Extension Albemarle/Charlottesville Office (www.ext.vt.edu) gratefully acknowledges the underwriting sponsorship of the following not-for-profit organizations without whom this course would not be possible, Trees Virginia (www.treesvirginia.org), and the Piedmont Master Gardeners Association (www.piedmontmastergardeners.org). In addition, I wish to thank all the local merchant and website calendar postings who have kindly assisted in the distribution of this course information with their customers and readers.

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For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.

February Landscape Activities

February Landscape Activities

28 January 2008

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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While the snow was providing a nice blanket and water source for our plants it has also given us an excuse to walk around a see what is happening in the landscape and maybe plan for the new season. If you find yourself looking for something to do with your kids while they are home from school try a tour of your landscape.

An eastern tent caterpillar egg mass.An eastern tent caterpillar egg mass.

Trees with large cavities in their trunks should be evaluated yearly as to whether or not they should be removed for safety reasons. When a cavity takes up over 75 percent of a limb or trunk, the wood could give way anytime. If you suspect a problem, contact an ISA certified arborist. Many are listed in your phone book under Tree.

Broadleaf evergreens can be pruned before new growth begins this spring. This will enable new growth to cover the cut surfaces and exposed inner branches.

Shrubs for spring planting should be ordered now. Bare root, deciduous types should be planted while still dormant, about one month before the average date of the last frost - this is usually in late April. Hardy, container-grown and balled and burlapped shrubs may be planted anytime, except during severe, cold weather. It is also time to transplant deciduous native plants if the ground is not too wet or too frozen.

Watch for signs of heaving among your small shrubs. The freezing and thawing of the ground can force shallow-rooted plants out of the soil. Replant any that have been heaved and mulch with 2 inches of organic material to reduce soil temperature fluctuation.

Try forcing branches of some shrubs to bloom during the bleak days of late winter and early spring. Possibilities include winter honeysuckle, fragrant viburnum, Japanese andromeda, mountain andromeda, azalea, rhododendron, and mountain laurel. Buds of native trees such as dogwood, spicebush, serviceberry, and redbud will blossom indoors as well. Make long, slanted cuts when collecting the branches and place the stems in a vase of water. Change the water every four days. They should bloom within three weeks.

Pussy willows that have been forced can be halted at any stage of their development simply by removing them from water. They will keep perfectly in dried arrangements for years.

Check valuable trees and shrubs for tent caterpillar egg masses and bagworms. Remove them to reduce the number of destructive pests this spring. Eastern tent caterpillar egg masses are gray and varnished looking and form a collar around twigs. Their nests are commonly found on wild cherry, apple, and crabapple, but may be found on hawthorn, maple, cherry, peach, pear and plum as well. Bagworms look somewhat like a pinecone hanging at the end of branches and seem to prefer arborvitae and eastern red cedar but can be found on many others.

Prune most shrubs and trees on warm days this month after the coldest weather is past in your area. Wait until after bloom to prune your spring-flowering shrubs in order to get maximum blossoms.

Remove honeysuckle and other weedy vines from deciduous plants while the plants are still leafless and easier to distinguish from the weeds.

Continue to water shrubs in your landscape throughout the winter on warmer days if the soil is dry. Evergreen plants transpire water from their leaves whenever the air temperature is above 40 degrees F.

Late winter is the time to prune many deciduous trees. Look over your plants now and remove dead, dying, unsightly parts of the tree, sprouts growing at or near the base of the tree trunk, crossed branches, and V-shaped crotches. Call your local Extension office if you are unsure when and how to prune each species.

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For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.

Vermicomposting

Vermicomposting

21 January 2008

Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580   fax: 434.872.4578

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Every home kitchen generates food scraps for disposal. Throwing these scraps in the garbage can create odor problems and adds to the volume of waste going to the landfill. A viable alternative to disposing of food scraps in the landfill or the sewer system is to compost them.

A diagram of a worm bin.A diagram of a worm bin.

Composting is a process by which organic materials are converted from an unstable product, which is likely to further decompose and create objectionable odors, to an increasingly more stable product that will store well without being offensive. A diverse population of microorganisms and invertebrates, called decomposers, performs this process. Most people think of composting as a pile of organic materials that slowly decomposes and creates heat. This is called thermophilic composting because it relies primarily on high-temperature tolerant microorganisms. Another form of composting is called vermicomposting.

In vermicomposting, the primary agents of decomposition are worms. They convert raw organic wastes to a nearly stable humus-like material. The main process by which organic materials are converted occurs as the wastes pass through a worm's gut and are digested by the worm. Worms stir and aerate the waste pile, so that turning is not required. Worms can stabilize organic materials faster than microorganisms because they grind the material, thus increasing its surface area and speeding decomposition by microorganisms. Material that actually passes through the gut of a worm is called castings.

Successful vermicomposting requires a worm bin that provides the appropriate environmental conditions for worms. Worms breathe through their skin and require an environment that is moist, but not so wet that they drown. The material in which they live should feel like a damp sponge and release a few drops of water when squeezed.

Various worm species have different temperature requirements. Eisenia fetida, the one recommended for a composting worm bin, can survive at temperatures between 35 and 100F but performs best between 65and 78F.

Worms do not have eyes, but they do have light receptors on their skin. They do not like light, and will quickly dig down into a bin to avoid it. For this reason, it is a good idea to provide a cover for your worm bin.

You can purchase a worm bin or you can build your own. A good rule of thumb for sizing a worm bin is this: you can process one-half pound of food scraps per day for each square foot of worm bin surface area. For example, a bin that is 18 inches by 24 inches (18/12 x 24/12) is 3 square feet in surface area and can process about 10.5 pounds of food a week (3 sq ft x 1/2 lb/ft sq/day x 7 days/week = 10.5 lbs).

A worm bin must be open enough to allow for good aeration. The bin should include a cover to minimize the attraction of fruit flies and other pests, but if a plastic lid is used, be sure and drill holes in it so air can get in. Bins can be made of a variety of materials--wood and plastic are common.

Place a six- to eight-inch layer of bedding material in the bin. Paper shredded into two-inch or narrower strips, including office paper and newspaper, cardboard, and well-composted horse or cow manure all make good bedding. Moisten the bedding material by soaking it in water, then drain it and squeeze out the excess moisture and fluff up the material to assure that it is well aerated.

Add one-half to one pound of worms for each square foot of surface area of worm bed. Give the worms time to burrow into the bedding material before you feed them. To discourage worms from leaving the bed, it is a good idea to leave a light on near the bin the first few days.

Worms can process a wide range of organic materials as long as the materials are not too salty or too acidic. Fruits, vegetables, coffee grounds and filters, and tea bags all make good worm food. Citrus fruit and peels should only be applied in small amounts because of their high acidity. Meat, bones, dairy products, fatty or greasy foods, and pet manure should not be placed in worm beds due to odor and pathogen concerns.

To feed the worms, bury the food in clumps, putting each feeding into one small space within the bin. Feeding once or twice a week is recommended. The bin should remain covered with the cardboard except when you are feeding. A new layer of moist bedding three to four inches thick should be placed on top of the bin about every two months.

Harvesting the Vermicompost: Every three to six months or when the bin begins to fill, the worms should be separated from the vermicompost if your objective is to generate more worms. Remove the worms from the vermicompost relatively early (after two to three months), and divide the worms into new bins. Giving the worms extra room will encourage high reproductive rates.

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For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.