Invaders in our Midst
PlantRight, a project run by Sustainable Conservation since 2005, has a goal: “to promote the use of noninvasive plants in gardening and landscaping in California.”
“Since 1993 Sustainable Conservation has partnered with the private sector to identify, implement and scale environmental solutions that make economic sense,” explained Greg Richardson, PlantRight project manager of Sustainable Conservation and speaker at the September meeting of the San Diego Horticultural Society. PlantRight, a project run by Sustainable Conservation since 2005, has a goal: “to promote the use of noninvasive plants in gardening and landscaping in California.” This project makes its recommendations based on scientific knowledge, and participation is voluntary. Richardson covered the impacts of planting invasions, what PlantRight does to prevent and correct these situations, and what we as citizens can do.
Why should we care about invasive plants? An invasive plant is one that has been introduced from another environment (aka foreign); it spreads on its own, and it causes some type of harm: financial, environmental, or it can be harmful to human health. These plants have a negative ecological impact as well. By taking over an area, diversity of fauna and flora disappears along with habitat and food. Invaders actually change the composition of the soil and alter “hydrology.” Water hyacinth completely cover a stream in the Sacramento delta. Deltas are essential to our environment. Normally their soil is very fertile resulting in a great deal of vegetation as well as a plethora of vertebrates.
Invasive plants also have an economic impact. They increase the intensity of wildfires. Agricultural yields are lost or diminished. Pampas grass, (Cortaderia selloana), with its deep roots and prodigious reproduction –each blossom has 10,000 seeds!—prohibited one farmer from using some of his land. Richardson showed us a picture of a pampas grass plant for sale at a San Diego County retail store with a sign that read
“Regular: 20’ tall; 13 ‘wide
“Dwarf: 3’ tall; 4’ wide
“Perennial grass
“Full sun
“Any amount of water.”
No wonder the poor farmer lost useable land. Weedy plants also have produced other economic impacts, including reduced land values and lost recreational area.
Historically invasive plants were introduced to California both intentionally or accidentally, according to one of Richardson’s sources (Bell et al., 2003). 48 per cent came as a result of horticultural or ornamental use. Seeds or other contaminants created another 37 percent of the problem. Dye, medicinal and forage uses are responsible for 13 per cent of their presence. Even the aquarium trade spreads about two per cent of these.
Invasive plants have several traits in common. They are abundant and propagate easily and rapidly. They are easily well-established and grow quickly. They oust native and noninvasive plants in their competition for water, food, and sunlight. Invasive plants are not fussy about soil types or weather conditions. They are also resistant to local pests and diseases. No wonder gardeners plant them. I thought I’d solved a ground cover problem with Vinca major. Now I am having a very hard time getting rid of it and keeping it from the neighboring canyon.
Many ornamental and invasive plants have similar traits. They have abundant flowers, they are easy to propagate, grow fast, and they are tolerant of soils and extremes in weather. They, too, are resistant to pests and disease.
In an effort to combat these problems, PlantRight, between 2006 and today, convened a steering committee and developed a regional plant list of invasives. Then they searched for and identified alternative plants. They wanted plants that had similar traits to those of the invaders but were controllable. The group considered size, shape, form foliage, flowers and when they peak. They also considered practicality: growth habits, ease of propagation, hardiness, and location should be similar. PlantRight has created outreach programs and other educational methods of bringing people’s awareness and concern of the problems created by the invaders. PlantRIght is also engaged in “Creating capability to screen plants for invasiveness on a commercial scale allowing for voluntary, preventative, and smarter plant choices that benefit our state’s environment and economy.”
This past year the group developed a partnership designed with the help of retail nursery owners and veterans in the nursery trade. Last spring it was initiated as a pilot program and now PlantRight is expanding it to become a statewide program. The participating stores commit to not selling locally invasive plants (per the list mentioned below) and to have the plant buyers complete the online PlantRight 101 training. In return the stores will receive the leading edge knowledge on invasive plant issues, will receive marketing materials and regular communication, and the stores will be promoted through PlantRight’s network.
How can we help or stop aggravating this situation? Richardson brought a few examples of their campaign. One is a chart which lists 19 of the most invasive plants with three or four recommended alternatives for each with similar traits and practicality. You may download this list from the PlantRight website at www.plantright.org. PlantRight chose plants that are already invasive, sold locally, and have a high impact or risk. The four most commonly sold today are Green Fountain Grass (pennisetum setaceum), Periwinkle (vinca major) which I planted, Invasive Brooms (there are several varieties), and Pampas Grass (Cortaderia selloana). The list also shows where these plants thrive. We can apply economic pressure by kindly asking our nurseries, their suppliers and wholesalers, and our landscape specialists to only buy and use locally non-invasive plants, by our not purchasing, specifying, or using invasive plants, and by letting our garden clubs, Homeowners’ Associations, nurseries, friends and neighbors know just how important this campaign is. .
Join us January 15 at the church, 4070 Jackdaw, from 6 p.m. to 8 p.m. Gabe Selak of the San Diego History Center will give us information on the garden Exposition of 1914. And Fausto Palafox will let us know how we can contribute to the 2014 Centennial celebration in Balboa Park in addition to the donation the Mission Hills Garden Club has already made.
Category: Life Style, Local News
