California Invasive Species Week is June 3-11. This is the perfect time to raise awareness about the impact of invasive plants on our natural ecosystems and the importance of making informed plant choices. Invasive species can have detrimental effects on local flora and fauna, often outcompeting other plants for resources and disrupting local ecosystems.
By selecting plants that are well-suited to your environment and not invasive, you can make a positive contribution to preserving California's diverse landscapes. Many invasive plants can be aesthetically pleasing and low-maintenance, making them a popular choice for gardeners. However, invasive plants can spread rapidly, taking over natural habitats and causing significant environmental damage. Invasive species often have few natural predators, enabling them to grow uncontrollably and outcompete other plants for resources like water, sunlight, and nutrients. This can lead to the loss of biodiversity, reduced habitat quality for wildlife, and increased risk of erosion and wildfires.
Examples of Invasive Plants in California:
1. Periwinkle (Vinca major)-This evergreen groundcover is a popular species because of its beautiful purple blooms. Periwinkleforms dense mats that can smother native plants and alter soil chemistry. Instead of periwinkle, try planting native groundcovers like California lilac (Ceanothus spp.) or hummingbird sage (Salvia spathacea).
2. Fountain grass (Pennisetum setaceum)-This ornamental grass is highly adaptable and has invaded many natural habitats, including grasslands and coastal sage scrub. Instead, opt for native grasses like purple needlegrass (Stipa pulchra) or deergrass (Muhlenbergia rigens) or the smaller version (Muhlenbergia dubia).
3. Pampas grass (Cortaderia selloana)-A tall, clumping grass with feathery blooms that can quickly dominate landscapes and outcompete native species. Consider planting native ornamental grasses such as blue grama grass (Bouteloua gracilis) or switchgrass (Panicum virgatum) as alternatives to pampas grass.
4. Tree of heaven (Ailanthus altissima)-This fast-growing tree can release chemicals that inhibit the growth of other plants and can sprout vigorously from root fragments. Plant California native trees like sycamore (Platanus racemosa) or western redbud (Cercis occidentalis) instead of the invasive tree of heaven.
Celebrate Invasive Species Week!
Additional Resources:
organization dedicated to protecting California's wildlands from invasive plants through
research, restoration, and education.
•California Native Plant Society (CNPS)-https://www.cnps.org/-CNPS is a non-profit
organization that promotes the understanding and appreciation of California's native plants and
preserves them in their natural habitat.
•PlantRight-https://plantright.org/-PlantRight works with California's nursey industry to keep
invasive plants out of our landscapes and promotes the sale of non-invasive alternatives.
- Author: Anne E Schellman
Why Not Move Firewood?
By bringing wood from home, you can unknowingly spread invasive pests and diseases that can harm trees. This includes dry, aged, and seasoned wood. Once you arrive at your destination, pests can emerge from the firewood and spread to the trees and forests where you camp. Invasive and hard-to-control pests kill several million native trees every year, causing environmental and economic problems.
Did you Know?
New infestations of tree-killing insects and diseases are often found in campgrounds and parks as a result of campers moving firewood!
This trip, tell your friends and family why you aren't bringing firewood. For more information about firewood pests and resources for finding good firewood, visit the Don't Move Firewood web site. To learn about many of the invasive wood-boring pests and associated diseases and problems, visit the UC IPM web site.
First posted on August 30, 2021
Anne Schellman has been the Coordinator for the Stanislaus County Master Gardeners since 2018.
/h4>/h4>What are invasive species?
Invasive species are organisms that are not indigenous, or native, to a particular area. Not all non-native species are invasive. To be considered invasive, an introduced plant species must meet these criteria, established by the EPA:
- Has few germination requirements, enabling it to adapt to the new environment easily
- Grows rapidly
- A prolific seed producer with effective dispersal systems
- Free of natural enemies and diseases
- Harms the environment, property, the economy, or the native plants and animals of the region
Plant Invasion in California's Central Valley
Of the invasive species listed on the California Invasive Plant Council Inventory, about 37% were accidentally introduced to the state. The remaining 63%, however, were intentionally introduced for purposes such as landscape ornamentals, soil stabilization, animal forage, human food, fiber, or medicinal.
Role of Plant Nurseries
University of California Integrated Pest Management has a Pest Notes link on invasive plants (http://ipm.ucanr.edu/PMG/PESTNOTES/pn74139.html) which lists the results of UC Master Gardener surveys of invasive plants for sale in California nurseries. Invasive plants rarely or no longer sold are listed.
What Can We Do?
Some ways you can help:
- Educate yourself regarding California's invasive horticultural plants, avoid planting them, and plant their alternatives for your garden.
- If an invasive plant already exists in your garden, at the very least, the plant should be kept in a vegetative state, so it does not reproduce. If you choose to remove these plants, it is important to make sure reproductive parts do not escape during the removal process.
- Do not to transport any reproductive parts such as fruit, seed, or root pieces by animal, human or vehicle to areas where plants have not been established. If you go camping or hiking in nature, clean your camping and hiking gear to ensure you are not accidentally spreading hitchhiking invasive species. If you bring a dog(s) along, clean their fur before leaving the park or wilderness area. Stay on designated trails and roads.
- Encourage local nurseries and garden centers not to sell invasive plants.
- Join removal efforts. Chances are you can find invasive species volunteer opportunities nearby. Check out your closest state or national park's website to see if they host invasive species walks—many organize half-day or day hikes where you learn to identify and help remove invasive plants.
Becoming a part of ongoing efforts to manage or eradicate the invasive non-native plant species in our state will help reduce their negative impacts on our natural resources. Planting native beauties in your garden is a simple way to help these plants survive and benefit the local fauna food webs.
Resources:
- UC IPM - Invasive Plants: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74139.html
- Plant Right - PlantRight is a project that was developed and managed by Sustainable Conservation, a California-based environmental nonprofit, from 2005-2019. In 2019, the new home of PlantRight became Plant California Alliance, which was formed through the merger of the California Association of Nurseries and Garden Centers, and the Nursery Growers Association. Includes a list of invasive plants in selected regions of CA and native substitutes: https://plantright.org/
- California Invasive Plant Council: https://www.cal-ipc.org/
- A list of plants not to put in your garden and alternatives: https://wildlife.ca.gov/Conservation/Plants/dont-plant-me
- PlayCleanGo provides ways for stopping the spread of invasive species: https://playcleango.org
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since 2020.
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