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! 

How Did the Western Monarchs Do This Winter in California?

In April I visited Pismo State Beach's Monarch Butterfly Grove. I knew there wouldn't be any western monarchs who overwintered remaining there (though I saw three flying around!), since they left a few weeks prior to begin their annual migration north. But I was curious: How did California's shrinking monarch population do this winter? The short answer is they did relatively well. . .but before getting to the details, let's review their current status.

Monarchs in Trouble

The colorful orange-and-black, magnificent monarch butterflies (Danaus plexippus) are the world's most recognized and beloved butterflies.  Yet, they are increasingly in danger of becoming extinct. An announcement last summer from International Union for Conservation of Nature (IUCN) announced the monarch butterfly had been put on its "Red List of Threatened Species as Endangered” due to habitat destruction, climate change, and pesticides, with the primary reason being reduction in milkweed plants that are so vital to their survival.

IUCN stated: "The western population is at greatest risk of extinction, having declined by an estimated 99.9%, from as many as 10 million to 1,914 butterflies between the 1980s and 2021.” In addition, "The larger eastern population also shrunk by 84% from 1996 to 2014. Concern remains as to whether enough butterflies survive to maintain the populations and prevent extinction."

This Year's Status

According to a recent article by Tara Duggan (https://www.pressreader.com/usa/san-francisco-chronicle-late-edition/20230201/281595244675872) the 2022 annual Thanksgiving count organized by Xerces Society showed relatively high numbers of western monarchs this year with over 330,000 found in overwintering sites throughout California's central coast. This is a significant increase from the winter of 2020-21 when fewer than 2,000 were counted and they were thought to be on the threshold of extinction. The 2021-2022 count the following year was much better, at 250,000.

At the Pismo Beach monarch sanctuary, a board showed some of the tallies made over the years:

1990 – 230,000

1995 – 150,000

2000 – 40,000

2005 – 32,000

2010 – 24,000

2015 – 28,000

2017 – 12,300

2019 – 6,000

2020 – 188

2021 – 22,700

2022 – 24,128

The same board also showed the 2022-2023 Pismo Beach sanctuary monarch migration season count (October-February) from their peak numbers after arriving from the north in autumn to their departure in mid-February for the beginning of their annual northward migration. Presumably the decreasing numbers between November and December was due to winter storms.

11/15/22 – 24,100

11/30/22 – 19,177

12/13/22 – 15,707

1/17/23 – 15,817

2/7/23 – 15,015

2/21/23 – 4,628

How You Can Help

• Plant nectar plants for the adults!  While caterpillars feed only on milkweed, the adult monarch feeds on nectar from flowers while migrating. Native plants with tubular or funnel shapes are particularly attractive and nutritious for all butterflies.
• Plant milkweed! This plant is crucial to monarchs' survival since it is the only plant females lay their eggs on and the only source of food for the emerging larvae. When possible, plant from seed. If you purchase plants ask the nursery or garden center if the grower treated the plants with pesticides. The best time to plant is in the fall months when it's cooler, at the start of the rainy season. Local native milkweed varieties include:

o   Asclepias fascicularis (Narrowleaf milkweed)

o   Asclepias speciosa (Showy milkweed)

o   Asclepias syriaca (Common milkweed)

o   Asclepias cordifolia (Heartleaf milkweed)

 

• Use UC Integrated Pest Management as a resource: (https://ipm.ucanr.edu/PMG/menu.homegarden.html). If you use a pesticide, avoid broad spectrum pesticides, selecting a pesticide for the specific pest/disease, or choose one that is less toxic such as horticultural oils and insecticidal soaps. Be sure to follow instructions and apply in early morning or late evening when pollinators are unlikely to be present.
• Get involved in the annual western monarch Thanksgiving and New Year counts (https://www.westernmonarchcount.org/) and/or tagging monarchs to monitor their migration patterns (https://www.monarchwatch.org/tagging/)

 

What Will the Future Bring for the Western Monarch?

This winter season's higher annual count numbers, while encouraging, are far below the historical counts, in the millions, of the 1980s. These beloved graceful creatures still have many challenges ahead. However, California state has invested over $1 million in monarch habitat restoration, including planting more milkweed, particularly here in the Central Valley, which is a part of their migratory flight path.

Only time will tell if their numbers will increase, but scientists say these efforts could help the western monarch population recover. By planting milkweed and native flowering plants in our gardens, we can be a part of this ongoing endeavor and hopefully be able to see more of these magnificent butterflies floating about in our gardens in the future.

To learn more about the life cycle and migration of the western monarch, read my article “Marvelous Monarchs” at https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=55249

 

Denise Godbout-Avant has been a UCCE Master Gardener with Stanislaus County since 2020

Are you interested in attracting native insects and pollinators to your garden? If so, join the UC Cooperative Extension Master Gardeners for a free class at a local Stanislaus County Library to learn more about California native plants.  

Sat, 3/4 at 2:00 p.m. – Empire Library
Tues, 3/7 at 6:00 p.m. – Salida Library
Wed, 3/8 at 2:30 p.m. – Patterson Library
Sat, 3/11 at 2:00 p.m. – Riverbank Library
Mon, 3/13 at 6:00 p.m. – Ceres Library
Tues, 3/14 at 6:00 p.m. – Oakdale Library
Wed, 3/22 at 6:00 p.m. – Turlock Library
Mon, 3/27 at 5:30 p.m. – Modesto Library    

Don't see your local library on our list? Contact them to request our classes.   

Healthy Soils Week is a campaign by the California Department of Food and Agriculture to highlight the importance of soil health. We thought our readers might be interested in some of the common questions our UCCE Stanislaus County Master Gardener Help Line receives about soils and fertilizers.

Do I need to test my garden soil?

The short answer is, “no.” Although many gardening magazines and websites advise gardeners to “test” their soil, it's unnecessary unless you suspect a major problem such as lead contamination or excess salts.

For a list of soil laboratories located in Stanislaus, Merced, Fresno, and Merced Counties, visit https://cemerced.ucanr.edu/ClimateSmartAg/HSP/SoilTest/Soil_Testing_Laboratories_in_Fresno_Madera_Merced_and_Stanislaus_Counties/

I think I have bad soil; nothing grows! What should I do?

The most common reason gardeners have trouble with soil is compaction, which results in poor drainage. This is often caused by compaction from heavy machinery or foot traffic. To improve soil, Master Gardeners recommend adding 4-6” of compost and mixing it into the soil. This is best done when soil is not wet. Since compost is an organic material that breaks down, continue to add it each season.

I think there are diseases in my soil, what should I spray?

Plant diseases do live in the soil, in fact, they are everywhere! However, these diseases need an opportunity to infect plants, such as a wound. Overwatering is a common cause of plant disease. Changing watering practices usually solves this problem.

Should I add manure to my vegetable garden soil?

Manure is a great addition to prepare your soil for a vegetable garden. However, it's best to use composted manure and to incorporate it into the soil several weeks before you plant. If fresh manure is used, plants may turn yellow due to the high concentration of salts.

How often should I fertilize my fruit trees?

Fruit trees work hard to produce a crop and do benefit from applications of fruit tree fertilizer in spring. Always follow the instructions on the package and never apply more than is recommended.

Have a soil, fertilizer, or other question topic we didn't answer?

Our Master Gardeners are available on Wednesdays from 9:00 a.m. to noon in person or by phone (209) 525-6802. You can also drop off a sample during business hours and we will get back to you, or fill out this survey (you can also attach photos if needed):

http://ucanr.edu/ask/ucmgstanislaus A Master Gardener will get back to you within 5 days of your request.

UCCE Stanislaus County Master Gardeners
3800 Cornucopia Way Ste A
Modesto, CA 95358

If you live in another county in California, you can find your local Master Gardener program by using this link https://mg.ucanr.edu/FindUs/