- Author: Erin Mahaney
Whenever I read about a plant that is described as a prolific self-seeder or self-sower, red flags go up. Is this code for an aggressive, invasive species that I'll regret growing in my yard? It is easy to check before making a purchase by conducting a quick search of California Invasive Plant Council's (Cal-IPC) plant database or PlantRight's priority invasive list.
Cal-IPC's mission is to protect California's environment and economy from invasive plants. (https://www.cal-ipc.org.) Cal-IPC maintains the California Invasive Plant Inventory, “a comprehensive list of invasive plants based on ecological impacts, as well as ‘Watch' plants that may become invasive in the future.” (https://www.cal-ipc.org/plants/inventory/.) Each plant is assessed using a criteria system with documented sources.
PlantRight works with California's nursery industry to limit invasive species and to promote the sale of exclusively non-invasive alternatives. (https://plantright.org.) According to PlantRight's website, it worked with “researchers at University of Washington and University of California, Davis to develop the PlantRight Plant Risk Evaluator (PRE) a method for determining a plant's potential for becoming invasive in any specific region.” PlantRight uses “this tool to determine which plants have a high risk of becoming invasive, which plants require more research, and which plants have a low risk of becoming invasive in a particular area.” (https://plantright.org/approach/.) Plants found to be high risk using PRE or are listed on Cal-IPC's Invasive Plant Inventory are placed on the priority invasive plant list.
Several years ago I planted Scabiosa atropurpurea, also known as pincushion flower, sweet Scabiosa, or Mourningbride. (There are other species of Scabiosa, such as Scabiosa caucasica, but this article focuses on Scabiosa atropurpurea.) The plant readily self-sows, but it is easy to remove when it gets too exuberant and begins to take over the garden plot.
I planted Scabiosa atropurpurea to use as a cut flower. The approximately 1-1.5” flowers resemble miniature pincushions on 18” stems. The flowers range from white to purple with colors in between, such as pink and lavender. In my yard, the plant blooms constantly from spring to late summer and attracts pollinators. It is low maintenance and grows to approximately 3' tall by 2' wide. It propagates by seeds. The flowers are a nice airy addition to a bouquet.
I thought I had checked the Cal-IPC rating when I purchased the plant, but regardless, I didn't think too much more about it until I recently saw several plants along a narrow dirt path in a local state recreation area. After that, I noticed them everywhere! They were often growing in disturbed areas along roads and trails.
According to Cal-IPC, Scabiosa atropurpurea is rated as “Watch.” It has a PRE rating of “high potential risk” by PlantRight and is listed as a plant to watch. (https://plantright.org/watch/scabiosa-atropurpurea/ .) PlantRight states that the plant was considered for addition to the invasive list from 2012 to 2014 but was not included at that time. Not surprisingly, it has naturalized in 18 California counties, including places in the San Francisco Bay area and central and south coast ranges of California. It has been listed as invasive in other countries and areas with a similar climate, such as Chile, New Zealand, and South Australia.
I don't plan on tearing out my Scabiosa just yet, but I will annually check Cal-IPC's and PlantRight's ratings for any change in status. I'll also attempt to minimize the invasive potential of the plant by keeping the plant contained in a specific area and deadheading spent flowers to limit seed production.
- Author: Loren Nelson
For the Fascination of Orchids 43rd Festival of Orchids and Exotic Plants at the Santa Ana Zoo The UC Master Gardeners of Orange County Information Booth will be open at the Zoo all weekend while you enjoy one of the largest and most highly evolved flowering plant families in the world.
Click the image to learn more and visit our Classes and Events Calendar page.
/h2>- Author: Christian Jordan
The Forestry Institute for Teachers (FIT) will be hosting two "FIT-Focus" sessions this Fall, including one in Plumas County. Please see the below message and attached flier for additional details:
- Author: Kathy Keatley Garvey
What we've been waiting for all season...
A migratory monarch butterfly fluttered into our Vacaville garden at noon today (Tuesday, Sept. 17) and nectared on a Mexican sunflower, Tithonia rotundifola.
Then she treated us to a butterfly ballet.
The Danaus plexippus touched down, nectared, shot up, dropped down, and did it all over again, while male territorial longhorned bees tried to make her stay short.
But she hung around for and hour.
Wings up...and she was gone.
And then another flashed by...
It's migratory monarch season.
- Author: Ben A Faber
There has been a recent expansion of Avocado Lace Bug into parts of the Carpinteria area. It was more or less located in the San Diego coastal area. It spreads mainly with people.......
Read about it at the UC-IPM website and the observations of Mark Hoddle, IPM Specialist at UC Riverside.
https://ipm.ucanr.edu/agriculture/avocado/avocado-lace-bug/#gsc.tab=0
- ALB does better in the slightly cooler more humid orchards in Oceanside when compared to the hotter inland Bonsall orchards.
- In the lab, under a fluctuating 24 hr temperate cycle similar to an avocado orchard in Escondido, optimal temps for development are a daily average of around 31-32oC (88-90oF)
- ALB life stage densities tend to be greater on leaves over June-Oct
- % leaf infestation measures (i.e., the proportion of sampled leaves with ALB lifestages) tend to be peak over fall-winter (Sept-Feb), but ALB densities on leaves are not as high as what are seen over June-Oct, there are basically more leaves with ALB and those per leaf densities are lower that numbers counted over June-Oct.
- Its hard to predict what the next season's ALB will be as lots of ALB are shed when leaves drop, but like persea mite, some manage to get back onto the new leaves to start the next round of infestations. Adults don't seem to be very flighty, well, at least they don't seem to exhibit mass flight activity that would suggest searching for new hosts as leaves deteriorate.
Keep your eyes open for a future edition of the CA Avocado Commission's magazine - From The Grove - for a more thorough discussion of the pest.
https://www.californiaavocadogrowers.com/publications/from-the-grove
images:
Adult
Adults, young, and fecal pellets
Leaf damage