- Author: Anne Marie Tsolinas
- Editor: Maggie Mah
- Editor: Cynthia Nations
It's the New Year and a gardener's thoughts naturally turn to planning new and interesting plants. For those of
us living on California's Central Coast, the mild climate and long growing season supports a wide variety of
vegetation. But beware: there are some plants that should be avoided because introducing them to your
landscape can have consequences that go far beyond filling an empty spot in your flower bed. Apart from
poison ivy and other classic plant “no-no's,” the plants that should be on your radar are known as “invasive
plant species.” So, whether you're planning a large landscaping project or a simple garden refresh, here's what
you need to know.
What is an “invasive” plant?
Invasive plants are usually not native to a particular region but once introduced, they become established very
quickly. If allowed to proliferate, they will out-compete the existing vegetation and ultimately, disrupt the
natural ecosystem. A dramatic example of “invasives” taking over can be seen in California's iconic “golden”
summer landscape. Prior to European settlement, the hills would have been green year-round with deep-
rooted perennial native grasses dotting the open ranges. The aggressive annual grasses and weeds that
accompanied the introduction of livestock quickly took over and today, only 1% of California's native grasses
remain.
What's the difference between “invasive plants” and “weeds”?
Although they are vexing and you might think of them as invasive, there's an important difference between
common garden weeds and plants that are truly and destructively invasive. Your typical weed actually requires
what is known as “human disturbance” to establish and persist. “Disturbance” means conventional gardening
activities like soil tillage, fertilizing, irrigation, etc. Invasive plants (whether they are introduced intentionally or
not) do not need any help from humans and readily escape from cultivated areas, infesting all kinds of habitats
including wildlands, rangelands, and even waterways.
What do invasive plants do to a natural habitat?
Invasive plants disrupt an ecosystem by out-competing other plants, thereby reducing the ability of natives and
other non-invasive plants to survive. This change creates a “domino effect,” impacting every organism that has
evolved in the pre-invasive habitat including birds, insects, and other wildlife who rely on native plants for
shelter and food.
Where do “invasive“ plants come from?
According to the California Invasive Plant Council, about 37% of the species listed on the CIPC Inventory were
introduced accidentally through contaminated seed or carried along on equipment, vehicles, animals, human
shoes, etc. The remaining 63% were intentionally introduced and of those, nearly 80% came via the nursery
industry for use in ornamental landscaping. We now know the harm that invasives can cause, but ironically, it
is also easy to understand why so many of them have become popular: they tend to be attractive, and they
grow very well!
Although many invasive plant species that were introduced in California are no longer sold, others are still
available, and their impacts can be seen on a grand scale. Of these, Pampas Grass (Cortaderia selloana or Cortaderia jubata) is the poster child. This spectacular South American native was brought to Santa Barbara and introduced commercially as an ornamental in the late 1800's. Extremely hardy and fast growing, with massive clumps up to 13 feet tall, stands of Pampas Grass can be seen along the entire length of California's coastal areas. The plant's sharp leaf blades can be harmful to animals and humans, rendering it undesirable as wildlife shelter or food source. It's also quite flammable.
The list of invasive plants that are still sold in California goes on. Among the varieties of highest concern and
that are known to be invasive in our coastal region are these: Green Fountain Grass (Pennistem setaceum);
Mexican Feathergrass (Stipa/Nassella tenuissimo) Water Hyacinth (Eichornia crassipe); Yellow Water Iris (Iris
pseudoacorus); Highway Iceplant (Carpobrotus edulis) and Periwinkle (Vinca major).
Why it matters
Invasive plants cause harm to the environment, the economy and even human health. Fast growing woody
invasives create higher fuel loads, causing fires to burn with greater intensity. Invasive aquatic plants clog
waterways and block livestock from gaining access to water. According to the California Invasive Plant Council,
the state's annual expenditures on control, monitoring and outreach to address the issue of invasive plants
total more than $82 million dollars. The actual environmental cost is much more difficult to determine but
researchers at Cornell University estimate that the damage done by invasive plants in the U.S. costs over $120
billion each year.
Although it is one of the most bio-diverse places in the world, California has limited and diminishing
untouched natural habitats and over 30% of its native species are threatened. In many areas of San Mateo
County, housing developments are adjacent to large areas of open space, which makes them especially
vulnerable to “invasion” by problematic plants. By choosing non-invasive plants for your garden, you will help
to protect these sensitive areas.
Resources
--Plant Right: an organization partnering with retail nurseries to prevent the spread of invasive plants sold in
California. Plant Right identifies alternative garden plants that are comparably beautiful and provide the same
utility as invasive plants. http://www.plantright.org
--California Native Plant Society: https://calscape.org
--Cal-IPC website: www.cal-ipc.org
- Author: Cynthia Nations
- Editor: Maggie Mah
It's December and ‘tis the season to…think about blackberries! Our cool northern California coastal areas provide the perfect climate for growing sweet, flavorful blackberries. So take a break from the holiday rush and get going on summer's delicious crop. Here's how to have a bountiful harvest.
About Blackberries
There are a number of hybrids and also thorny and thornless varieties but, ultimately, there are two basic types of blackberries: trailing (with canes that are not self-supporting) or erect (with stiff, arching canes that are somewhat self-supporting.) Both types benefit from a trellis support and all varieties have similar growing requirements. To do their best, blackberries (also known as caneberries, bushberries and dewberries) need to be in a location that receives partial sun and in soil that is slightly acidic with a pH of about 6 to 6.5. Ensure that the soil is rich in organic matter and topped with a layer of organic mulch. Plants will need regular irrigation during the growing season so carefully check the soil at the base of the plant to determine if watering is sufficient. Root areas should be cool and moist but not wet and should not be allowed to dry out. Once established, apply compost or manure in late fall or early winter to allow rain to leach excess salts and as soon as the plants begin to put forth new growth in early spring, apply an organic granular fertilizer (20-20-20) around the base of the plants. This will provide the nitrogen needed for vigorous growth and fruit production.
How and What to Prune
A blackberry plant can live for many years but fruit grows only on the short lateral shoots of two-year-old canes (“floricanes”)which then die back after berry production is over. In spring, you can “tip prune” to force the canes to branch out and create more lateral shoots for fruit to grow on. Use sharp, clean pruning shears and cut to about 24 inches. If the canes are shorter than 24 inches, prune the top inch of the cane. In the fall, after fruiting is complete, prune to remove diseased, dead and spent canes by cutting to ground level. This will encourage the plant to produce more first year canes (“primocanes”), which will mean more fruit-producing canes the following year. If you already have blackberry vines, prune them now.
How and When to Plant
December and January are good months to plant dormant blackberries, but potted vines can also be planted in spring or summer. For bare root plants, trim the dead roots and dig a planting hole just large enough to accommodate the roots. Cover the roots with soil and press firmly to remove air pockets. Water thoroughly to settle the soil. After planting, cover the soil with mulch. Blackberry cultivars can be spread 3 to 4 feet apart in the row with 8 to 10 feet between rows. Cut the canes on newly set plants to 6 inches at planting time.
When to Pick
Blackberries do not continue to ripen once they are picked so it's important to pick fruit at the peak of flavor and sweetness. Since different varieties ripen at different times, you can extend your berry season by planting a few different kinds. Erect blackberry cultivars include: Black Satin, Cherokee, Cheyenne, Chester, Darro, Hull Thornless, Shawnee, and Triple Crown. Trailing blackberry cultivars include: Boysen, Kotata, Logan, Marion, Ollalie, and Silvan. (More information: https://ucanr.edu/sites/gardenweb/Berries/?uid=4&ds=466).
Troubleshooting
Purchasing certified disease-free plants from a nursery is a good practice. Although it is easy to propagate your own berry plants from canes, plants derived from another garden or grown near wild blackberry bushes could introduce unwanted diseases. If your blackberry plant looks healthy and blooms, but grows misshapen fruit or no fruit at all, chances are that your blackberry plants are affected by a blackberry disease. If you have more than one variety, one type may fruit while another, susceptible variety may not. On the coast, Anthracnose is a common fungal disease that tends to attack plants when the weather is cool and wet. The fungus can be spotted when the blackberry fruit starts to ripen but then wilts or turns brown.
If you decide to use a fungicide, it's important to determine if a fungus is indeed the culprit. Since symptoms could be due to something other than a fungus, using a fungicide might be a waste of money and do more harm than good. Contact the UC Master Gardeners Helpline (Phone: (650) 276-7430; Email: mgsmsf@ucanr.edu), to provide information and a photo of the problem. The Helpline will help determine if using a fungicide is necessary and, if so, what types of safe fungicides are best to use.
Insects (aphids, cutworms, thrips, mites, etc.) can also cause fruiting problems with blackberry plants. Check the bush carefully, particularly the undersides of leaves to see if the plant has unwanted pests. It is important to first identify the pest before determining the treatment. Sometimes the treatment could be as simple as hosing off aphids or spraying the pests with soapy water. Detailed information about blackberry diseases, pests, and treatments can be found here: http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/blackberries.html
Cynthia Nations is a UC Master Gardener who continues to experiment with different blackberry cultivars coast side. This article was edited by UC Master Gardener, Maggie Mah.
- Author/Editor: Cynthia Nations
- Author/Editor: Maggie Mah
Growing more fruits and vegetables than your family can eat is a great gardening “problem” to have. What did you grow last year that you shared with others? You probably won't have to think very long, because sharing is powerful, makes everyone happy, and creates lasting memories. During the contemporary plague known as COVID, many of us turned to our gardens as a way to maintain our physical and emotional well-being. Now, as we (hopefully) return to some sort of normal, our gardens can help us reconnect to others in very meaningful ways.
Vegetable gardens reach their peak in late summer. Tomatoes ripen at a rapid pace, squash and beans can't be harvested fast enough and people in your household start rolling their eyes at your latest zucchini creations. Figuring out what to do with all that fresh produce can be a dilemma. Some may channel their pioneering (or hippie) forebears by drying, freezing, or canning. All of these methods of preservation are laudable, but frankly take more time, space, and know-how than most of us have. Rather than having your produce go to waste or ending up in the compost pile, share the abundance you created with friends, neighbors, and even your whole community. Although this might provoke images of going door to door with a wheelbarrow (or providing a really good rationale for acquiring a vintage pick-up truck!) you can donate your fresh produce to local food banks. On a larger scale, two organizations are partnering to create a sustainable system of providing high quality vegetables and fruits to people with limited resources.
Each Green Corner (EGC, https://www.eachgreencorner.org) is an all-volunteer group that works to bridge the gap between home gardeners and places where members of the community can obtain fresh, healthy produce, thereby strengthening the connection between food security and public health. Inspired by the fact that interest in non-commercial agriculture was increasing throughout the area, the all-volunteer group saw the potential to leverage smaller, underutilized plots of land scattered throughout the area (residences, schools, parks, etc.) to grow fresh food for the culturally diverse population in the greater community. EGC works with home gardeners (each person “hosting” a garden is referred to as a “Garden Steward”) educating them to grow produce using sustainable practices that can supply produce to food-insecure community members in San Mateo County. EGC-supported gardens are not limited to private residences, however. Any underutilized plot of land, such as out-of-the-way areas of schools, community properties and other public spaces are considered fair game for creating gardens. In combination, each small-scale effort becomes part of something far more significant in the effort to create and maintain a healthier world.
EGC was founded as an official 501(c)(3) not-for-profit organization in 2018 and since then has worked to educate and assist people to harvest excess produce from each garden and donate the surplus to local non-profit food distribution organizations. To date, EGC has donated over 6500 pounds of produce from 15 sites throughout San Mateo County. EGC was recently named one of San Mateo County's Sustainability Heroes of 2022 (See https://sustainablesanmateo.org/). Each year, Sustainable San Mateo County (SSMC) recognizes the efforts of local organizations that make significant contributions in protecting the planet.
The University of California Master Gardeners Harvest for Neighbors project (H4N - https://smsf- mastergardeners.ucanr.edu/projects/harvest-for-neighbors/) aims to reduce food waste by ensuring all fruits and vegetables grown locally get used, to introduce more people to gardening, and to promote best practices of sustainable gardening. With the missions of H4N and Each Green Corner so closely aligned, it seemed only natural that they should work together. The two organizations have recently formed a partnership wherein UC Master Gardeners provide research, education, experience, and expertise to EGC “Garden Stewards” to assist them in developing and maintaining their gardens.
Bottom line: working together in gardens and donating fresh produce to food pantries in the Bay Area fosters a win-win scenario for all. Growers who are passionate about working in the garden can feel confident knowing that their skills have made a difference as their produce is shared.
If you like the idea of working with others to promote better nutrition and quality of life in your community but can't go all-in, there are great options to consider. One is to grow an extra row of whatever fruit or vegetable you might have in your garden. Another might be to volunteer at one of the Each Green Corner locations. More information can be found in the links provided above. The websites listed also contain information about food pantries that welcome home-grown food in the Bay Area.
The article was written and edited by UC Master Gardeners Cynthia Nations and Maggie Mah.
- Author: Maggie Mah
- Editor: Cynthia Nations
- Editor: Terry Lyngso
- Editor: Kelly Torikai
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We're learning a lot about micro-climates and how small variations in temperature, humidity, wind, and other factors determine what grows best in a particular location. There's not much one can do about any of those factors, but there is something you can do that will have a positive impact, no matter where you live or what might be going on in Earth's biosphere: you can improve any garden anywhere by improving the soil. It's easy to do, the results are dramatic, and the benefits extend beyond your garden.
Sand, Silt and Clay: Texture is here to stay
The soil beneath your feet has a basic nature according to the geological history of your location and the type of “parent material” (rocks) from which it was formed. “Soil texture” is defined according to the percentages of sand, silt, and clay. This is good to know because different soil textures have different properties and will affect things like water filtration and nutrient availability. Soil texture does not include organic matter. Here's where things get interesting: you cannot change soil texture, but you can make major changes to how it functions by adding organic matter.
Imagine a pile of rocks, a bucket of sand or a lump of clay as various types of soil texture. Now imagine trying to grow something in any of them. Without organic matter, it's not going to happen. So, what is organic matter? Simply put, organic matter is anything that is alive, or was once alive: plants, animals, insects, microbes are all broken down by the microbial community. Organic matter improves the capacity of soil to infiltrate and hold onto water and nutrients, and this makes it possible for plants to grow and thrive.
Healthy Soil: It's like a good party
Soil with plenty of organic matter teems with life. Like a good party, there are lots of interesting guests (microbes such as bacteria and fungi. Also insects, etc.), plenty of good food and drink (available nutrients and water), enough room to move (loose, non-compacted soil), and plenty of action. Viewed through a powerful microscope, a handful of healthy soil would reveal billions of organisms doing their job. Although organic matter may only make up 5% of your soil, it is the 10% of microbial life in the organic matter that is essential for all soil functions like water infiltration, nutrient cycling, carbon sequestration and plant health.
At the other end of the spectrum is unhealthy soil. Like a ghost town, the microbial residents have vanished, and the place is dusty. It cannot infiltrate and retain water effectively and is easily eroded. This sad state can be caused by several things including no plant or mulch cover, repeated tilling, compaction, excessive use of chemical fertilizers, pesticides and herbicides.
How can I be sure my soil is healthy?
Effective use of organic materials such as compost can provide steady supplies of nutrients. This will create and maintain a desirable environment for the beneficial microorganisms that are essential for healthy soil. Did you know that leaving lawn clippings in place and allowing fallen leaves to remain is an effortless way to improve your soil? These are organic materials that break down quickly.
Keep it covered: Keeping soil covered with plants, leaves and organic mulch moderates soil temperature, conserves moisture, and prevents erosion while adding habitat and providing food for beneficial organisms. Remember all mulch eventually breaks down, so more needs to be applied either from leaves dropped by plants or from mulch applied by you.
Do not disturb: Avoid tilling or turning the soil. Instead, add a thin 3⁄8” layer of compost with a 2-3” layer of mulch on top and let nature do the work of aerating and opening things up. Be careful with leaf blowers by limiting their use to hardscape areas. This helps preserve valuable organic matter and topsoil and the beneficial microbes that live there.
Beyond the Garden Wall: Healthy soil has global implications
Carbon capture: Unlike carbon in the atmosphere, carbon stored in the soil is a good thing. Through a process known as “carbon sequestration,” soils can retain carbon in the form of organic matter, some of which is stable and some of which cycles. It is important to remember that plants and soil life are responsible for development of the organic matter that is held in soils. Recent studies show that soils alone trap about 25 percent of the world's annual fossil fuel emissions. So, if we want to sequester more carbon in the soil, we need more plants growing in a microbial diverse community.
Pesticide reduction: Just as healthy humans can more easily fight off diseases, plants grown in healthy soil are more naturally resistant to diseases. That means less reliance on pesticides.
Water efficiency: Healthy soil acts like a sponge: it holds onto water, so water is available to plants over an extended period. Good news for our climate with only winter rainfall. According to the USDA, every 1% increase in organic matter increases the soil's water holding capacity by as much as 25,000 gallons per acre. When water is stored in the ground, it also recharges groundwater. Healthy soil improves water quality by filtering out pollutants.
For more information on improving your soil, go to: https://marinmg.ucanr.edu/BASICS/SOIL_813/
For more help with your garden, ask a Master Gardener! Send your questions to mailto:mgsmsf@ucanr.edu
This article was written by Maggie Mah (who is surprised to be so excited about compost) and edited by Cynthia Nations, Terry Lyngso, Kelly Torikai, Nancy Kruberg, and Nick Landolfi, SM/SF UC Master Gardeners.
- Author: Cynthia Nations
- Author: Maggie Mah
- Editor: Maggie Mah
Like many things in life, the best results are achieved by working together. This is especially true with plants!
Although you may have heard about plants that are thought to aid in insect control, disease prevention or the benefits of pairing particular plants in certain areas, the latest research on “companion planting” goes far beyond random recommendations or traditional lore. The latest research reveals the need to look at our gardens in a more holistic way: as ecosystems where plants interact with each other to create a healthy, bio-diverse place. Key to understanding this concept is that plants actively affect each other. They do this through fungal associations, chemical messaging and allelopathy, which is the ability of one plant's chemistry to affect the growth and development of another. They also share resources, attract pest predators, and improve each other's nutrient availability and absorption.
When we plant one type of plant in an area, whether it's tomatoes or other vegetables, we create what is known as a “monoculture.” Although it makes large scale farming possible, monoculture leads to increased reliance on pesticides and chemical fertilizers. However, when we choose different plants to grow together, we create a “polyculture,” which leads to biodiversity. Why is this important? Biodiversity means a more stable environment for veggies and other plants to thrive by enhancing nutrient cycling, water conservation, fewer pests and ultimately, more carbon sequestration.
What is modern research-based companion planting? Scientists prefer terms like inter-cropping or inter-planting to describe creating a polyculture to achieve desired benefits in the garden. Using a scientific approach helps us to understand the why and how of successful planting combinations.
Jessica Walliser, author of “Plant Partners: Science-Based Companion Planting Strategies for the Vegetable Garden,” provides plant partnerships that have undergone scientific scrutiny and shares plant pairings that help to reduce pests, minimize disease, support pollination and improve soil fertility. Walliser's findings are the basis of this article.
Using science as your guide, gardening with companion plants will help you learn about your own unique corner of the world. Have fun as you experiment with plant combinations and create a bio-diverse habitat outside your door. You'll look at your garden in a whole new way as you observe the changes in color and texture--all the while appreciating the overall health in your garden.
Cynthia Nations is a UC Master Gardener who is currently learning and employing companion partnerships in her garden in El Granada. The article was co-authored and edited by Maggie Mah, a UC Master Gardener, who is trying to catch up with Cynthia Nations.
