Introduced roadside vegetation a problem in California
The City of Poway has a population of approximately 51,000 residents and is located in northeast San Diego County. Poway is known as “The City in the Country” and prides itself on the fact that over half of the City’s area is preserved as dedicated open space.
Poway has a population of approximately 50,000 and is located in northeast San Diego County. Poway is known as “The City in the Country” and prides itself on the fact that over half of the City’s 39.4 square-mile (100km2) area is preserved as dedicated open space.
San Diego is very dry, only receiving 4.5 inches (120mm) of rainfall last year, so we learnt a lot about how they manage their public open space vegetation with limited rainfall. A large percentage of their state controlled roadsides are planted with a monoculture of ‘Ice Plant’ Carpobrotus edulis.
In the early 1900s C. edulis was brought to California from South Africa to stabilise soil along railroad tracks and was later put to use on road networks for similar purposes. Thousands of acres were planted in California until the 1970s. It easily spreads by seed (hundreds per fruit) and from segmentation (any shoot segment can produce roots). Its succulent foliage, bright magenta or yellow flowers, and resistance to some harsh coastal climatic conditions (salt) have also made it a favoured garden plant. The Ice Plant was for several decades widely promoted as an ornamental plant, and it is still available at some nurseries. Ice Plant foliage can turn a vibrant red to yellow in colour.
The Ice Plant is still abundant along highways, beaches, on military bases, and in other public and private landscapes. It spreads beyond landscape plantings and has invaded foredune, dune scrub, coastal bluff scrub, coastal prairie, and most recently maritime chaparral communities. In California, the Ice Plant is found in coastal habitats from north of Eureka, California, south at least as far as Rosarito in Baja California.
The Ice Plant poses a serious ecological problem, forming vast mono specific zones, lowering biodiversity, and competing directly with several threatened or endangered plant species for nutrients, water, light, and space. This species introduction, brought in to assist in erosion control and to reduce maintenance sends a warning to roadside vegetation managers that care must be taken when species to ensure they are beneficial to the environment they are used in and not an ecological disaster.
We would like to know what weed species you are battling with in your built environment. Do you to have introduced species that you are finding difficult to manage? What can we do in the future to ensure we do not make the same mistakes in the future?
We welcome your comments, questions and feedback. Visit our website to view photos of the harsh roadside environment and the use of Ice Plant in roadside situations.
Poway has a population of approximately 50,000 and is located in northeast San Diego County. Poway is known as “The City in the Country” and prides itself on the fact that over half of the City’s 39.4 square-mile (100km2) area is preserved as dedicated open space.
San Diego is very dry, only receiving 4.5 inches (120mm) of rainfall last year, so we learnt a lot about how they manage their public open space vegetation with limited rainfall. A large percentage of their state controlled roadsides are planted with a monoculture of ‘Ice Plant’ Carpobrotus edulis.
In the early 1900s C. edulis was brought to California from South Africa to stabilise soil along railroad tracks and was later put to use on road networks for similar purposes. Thousands of acres were planted in California until the 1970s. It easily spreads by seed (hundreds per fruit) and from segmentation (any shoot segment can produce roots). Its succulent foliage, bright magenta or yellow flowers, and resistance to some harsh coastal climatic conditions (salt) have also made it a favoured garden plant. The Ice Plant was for several decades widely promoted as an ornamental plant, and it is still available at some nurseries. Ice Plant foliage can turn a vibrant red to yellow in colour.
The Ice Plant is still abundant along highways, beaches, on military bases, and in other public and private landscapes. It spreads beyond landscape plantings and has invaded foredune, dune scrub, coastal bluff scrub, coastal prairie, and most recently maritime chaparral communities. In California, the Ice Plant is found in coastal habitats from north of Eureka, California, south at least as far as Rosarito in Baja California.
The Ice Plant poses a serious ecological problem, forming vast mono specific zones, lowering biodiversity, and competing directly with several threatened or endangered plant species for nutrients, water, light, and space. This species introduction, brought in to assist in erosion control and to reduce maintenance sends a warning to roadside vegetation managers that care must be taken when species to ensure they are beneficial to the environment they are used in and not an ecological disaster.
We would like to know what weed species you are battling with in your built environment. Do you to have introduced species that you are finding difficult to manage? What can we do in the future to ensure we do not make the same mistakes in the future?
We welcome your comments, questions and feedback. Visit our website to view photos of the harsh roadside environment and the use of Ice Plant in roadside situations.
Labels: harsh roadside environment, Ice Plant, species introduction, warning to roadside vegetation managers
posted by Steve Hampton at
2:48 PM
2 Comments:
Are there plants you can introduce to help control erosion that don't take over and cause unwanted problems? BDG
By
Anonymous, At
December 2, 2008 at 4:11 PM
It really would depend on your particular situation and what plants were available in your region. Quite often suitable native species are overlooked for exotic plants that are perceived to be a cost effective solution. However, in such sitations it is rare that the ongoing maintenance costs or impact on the environment are considered.
It is our hope that through our research, we will be able to develop best practice guidelines that integrate vegetation management decision-making processes into vegetation management planning, design, construction, and maintenance.
By
Steve Hampton, At
December 12, 2008 at 5:00 PM
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