- Author: Ann Edahl
There are hundreds of varieties of mint. The two most common are peppermint (Mentha piperata) and spearmint (Mentha spicata). Peppermint is used mostly for cooking, flavoring, and oils — for example, in gum, soaps and candy. Spearmint is often used fresh, such as in teas, other drinks and sauces (mint sauce, anyone?).
Other mint types that are usually easy to find include apple mint, pineapple mint and chocolate mint. And yes, chocolate mint, a type of peppermint, really does smell like a chocolate mint when you rub a leaf between your fingers!
Mint is a hardy perennial, meaning the plant comes back every year, and it can handle temperatures well below freezing. Depending on the variety, mint plants grow about one- to two-feet tall. They can grow in lots of different types of soil but prefer rich soil. Mint grows in full sun to part shade and needs moderate water. Its ability to thrive in part shade is a plus for many gardeners.
Although mint is often disease and pest free, it can be susceptible to rust and powdery mildew, two diseases caused by fungi. Some insects can also cause damage to mint, including aphids, leafhoppers, thrips, spider mites, mint caterpillar and mint root borer. See the University of California IPM (integrated pest management) mint page, linked below, for more information and tips on controlling these diseases and pests.
How do you grow mint? Mint spreads naturally by runners, by what we call “layering” — where the mint begins rooting where the horizontal stems you see growing above the soil surface touch the soil. You can also grow mint from seed, by dividing the plant and with root cuttings — mint roots in water quite easily and you might even have luck with rooting it by sticking a stem of mint directly into the soil. Which brings us to the biggest point to consider when deciding to grow mint: its tendency to spread easily and fast!
Mint is vigorous and will spread rapidly if there is no physical barrier to stop it. To help prevent mint from becoming a nuisance, the solution is to plant it in a container. The pot should be at least six inches deep, and placing a saucer or some type of paver between the pot and the ground will prevent the mint from eventually escaping through the drainage hole. You will want to give it a good watering when the soil is dry, especially during the heat of the summer. The smaller the pot, the faster the soil will dry out. But even if you wait too long and the mint wilts, chances are it will come back. It is one hearty (and hardy) herb!
Or you can grow mint in the ground but in a large pot buried in the soil. When burying the pot, do not bury it flush with the soil, but make sure to leave a one- to two-inch lip sticking out of the ground. This will help keep the mint contained. Even then, be on the watch for mint runners trying to escape over the lip since it really, really wants to spread! Also, if planting mint in a container in the ground, make sure it's a sturdy pot. Terra cotta is okay but may disintegrate over time. Five-gallon-size paint buckets are the perfect size, deep enough that the roots of the mint cannot easily escape. Be sure to add drainage holes on the bottom if you go this route.
Now that you've planted your mint, you'll soon be ready to harvest! It's best to wait to harvest after the plant has reached three to four inches. Young leaves will have the best flavor although you can harvest at any time. To conserve the flavor in the leaves, pinch off any flowers that form.
And you're set! On our next 100-degree day, go out in the morning, pick some of those mint leaves — spearmint and apple mint are two of my favorites — steep them for a few hours in a pitcher of ice water and get ready to be refreshed!
Read more:
UC IPM. Pests in Gardens and Landscapes: Mint — Mentha ssp.
UCANR Cooperative Extension–Sacramento County. Environmental Horticulture Notes: Culinary Herb Profiles. EHN 70.
- Author: Cynthia Zimmerman
"We're not talking about one hungry plant here, we're talking about world conquest." – Seymour, Little Shop of Horrors.
There can be undesirable consequences to the establishment of invasive species. Invasive weeds often are responsible for drastic changes to native ecosystems, such as interfering with natural habitat and food sources for animals, causing wildfires to be more frequent and intense, and lowering water tables by invasive trees that have deep rooting systems. Some plants even alter soil chemistry making it difficult for natives to survive.
These invasive species move out of their home ranges into new areas either by wind, birds or animals, or with human assistance that may be deliberate or accidental. This has been happening since the beginning of time. Humans have deliberately, and at times inadvertently, moved plant species from one region to another. With the development of high speed travel that doesn't take months to circumnavigate the globe, plants move with ease into areas where they were never before known. At times, plants that were once desirable and beneficial while under human control in gardens become a problem as they escape and start to colonize and breed in areas where they are not wanted. According to the California Invasive Plant Council, “The spread of invasive plants is one of the most significant threats to the native plant species and vegetation communities of the state, second only to habitat destruction.”
It's up to all of us to take some responsibility for reducing the problems caused by invasive species. One simple step is careful selection of garden plants by using species that are not likely to be invasive. The following plants are at the top of the list of invasive plants that should not be planted in California:
- Pampas grass (Cortaderia selloana)
- Green fountain grass (Pennisetum setaceum)
- Mexican feather grass (Stipa/Nassella tenuissima)
- Highway iceplant (Carpobrotus edulis)
- Periwinkle (Vinca Major)
- Yellow flag iris (Iris pseudacorus)
Instead of the above listed plants, try the alternatives shown on the Plant Right invasive plant website.
For a list with pictures of suggested non-invasive plants for California, take a look at Plant Right's better plant choices.
For further information about invasive plant species and what you can do to help, see the following websites:
Don't Plant a Pest! Central Valley
Don't Plant a Pest! California Invasive Plant Council (cal-ipc.org)
Invasive Plant Checklist for California Landscaping (pdf)
The 39 Most Invasive Plant Species in California
16 Invasive Species Sold at Garden Centers You Should Never Buy
Native Plants and Invasive Species
(Originally written April 2021. Updated May 2024)
- Author: Jeannette Warnert
The summer months in Fresno County are ideal for garden soil solarization, an environmentally sound way to kill weeds, insect pests and soil pathogens with free and naturally abundant solar energy. No pesticides are used in the process.
The greenhouse effect of the sun's rays on clear plastic can heat up the top 12 to 18 inches of the soil to as high as 145 degrees under perfect conditions. Excellent pest control can be achieved by maintaining the soil at 110 to 125 degrees in the top 6 inches, according to the UC Integrated Pest Management Program. The hot soil environment will kill such pests as nematodes, grubs, cutworms, beetles and snail eggs. Disease pathogens, such as fungi that cause verticillium and fusarium wilt, die.
There are downsides. Solarization requires taking garden space out of production during the growing season for 4 to 6 weeks, but future garden success is likely worth the sacrifice. The process may also kill some beneficial soil organisms, though UC IPM reports that many beneficials survive solarization or quickly recolonize the soil afterward. Earthworms, often present in healthy soil, burrow deeper to escape the heat and return when the treatment ends.
To solarize soil, smooth an area and water uniformly to 12 inches deep, then cover it with clear plastic. Rolls of clear plastic “drop cloth” are available in the paint sections of large home stores and online. Thin plastic (1 millimeter) provides greater heating but is susceptible to tearing; slightly thicker plastic (1.5 to 2 millimeters) is better for windy areas. Secure the plastic tightly over the soil with shovelfuls of soil, lumber, rocks, landscape staples or anything that will keep the breeze from catching the edges. Leave the area undisturbed for 4 to 6 weeks or longer in cooler temperatures or if the area is shaded part of the day.
After solarization, the bed can be planted immediately with seeds or transplants.
Fresno County Master Gardener Emily LaRue is solarizing a garden bed at the program's demonstration garden, 1750 N. Winery Ave., Fresno. The Garden of the Sun is open to public visitors from 9 to 11 a.m. Mondays, Wednesdays and Fridays.
For more information on soil solarization, see the UC IPM Pest Note: Soil Solarization for Gardens & Landscapes.
- Author: Jeannette Warnert
Weeds present a serious economic problem for farmers, a major headache for vegetable gardeners, and an unattractive appearance in landscapes, but herbicides are not the only solution.
“Studies have shown that more than 70 percent of weeds in lawns and ornamental plantings can be controlled based on good cultural practices,” said Dr. Clebson G. Gonçalves, a horticulture expert and farm advisor with UC Cooperative Extension in Lake and Mendocino counties. He spoke about springtime weed identification and management during a recent urban horticulture webinar offered by the UC Integrated Pest Management Program. “To control weeds, start with good soil; choose suitable plants; and mow, prune, water, and control pests to ensure dense and healthy turf and ornamentals.”
There are several definitions for the term “weeds,” but generally speaking, it can be defined as a plant out of place. Gonçalves used common bermudagrass as an example.
“Bermudagrass is one of the most desirable grass species for golf courses, sports fields, and residential lawns. But out of place, it's extremely difficult to control. It's adaptable to a wide range of environments and can reproduce by rhizome, stolon, and seeds,” he said.
When deciding how to control weeds in lawns and landscapes, Gonçalves suggests gardeners start by identifying the species. The Weed Research and Information Center at the University of California, Davis, offers a free online weed identification tool. Users input characteristics of the weeds – such as weed type (grasslike, broadleaf, woody), where the weed was found, leaf characteristics, stem characteristics, floral characteristics, life cycle, growth habit, etc. – and the tool offers potential species. The UC IPM Program maintains a weed photo gallery of species commonly found in California.
Knowing the species helps determine best practices for control. For example, nutsedge is a grass-like weed that develops nut-like tubers on the roots. The tubers are key to nutsedge survival. Dig deeply into the soil to remove the tubers on mature nutsedge roots. To limit tuber production, remove small nutsedge plants before they have 5 to 6 leaves.
Gonçalves suggests following the principles of integrated pest management to control the weeds by first considering practices that are effective and environmentally sound.
Preventative
- Avoid bringing weeds into your garden and landscape in the first place. Gonçalves suggests using weed-free soil and compost. “It's better to spend a little more money up front when you buy topsoil and compost, than spending even more money later for weed control,” he said.
- Inspect plants at nurseries before bringing them home to see if there are any weeds in or under the pot.
- Clean the mower between lawns. “This is especially important for landscaping companies that work in different locations on the same day. It is important to clean all the equipment before starting in a different location.,” Gonçalves said.
- Never let weeds go to seed. “A lot of species – such as dandelions, bermudagrass, and annual bluegrass – can produce a new seed head very quickly,” Gonçalves said. “If you mow every other week, that's enough time for these weeds to produce new seed heads and disperse seeds. It's better to mow once a week or even more often to prevent the production of seed.”
Cultural
- Soil aeration. “It's very important to alleviate soil compaction in established turf. You will have better water infiltration, greater nutrient availability and more oxygen underground, which promotes plant health and growth above and below the ground,” Gonçalves said.
- Don't leave soil exposed. Limit the area for weeds to grow by utilizing dense plantings. “When you have light and moisture, you have weeds coming up,” he said.
- Mow uniformly at a height of three inches or more. The tall and dense turfgrass canopy will shade the ground and prevent the germination of several weed species.
- Fertilize uniformly.
Mechanical
- Pulling weeds. “Every weed can be controlled by hand. If you have the time to pull by hand, that is recommended. There is some pleasure in pulling weeds. It can be used as therapy,” Gonçalves said.
- Mulches. Wood chips, stone, leaves or compost – especially on top of landscape fabric – can control weeds.
- Flaming. Very effective, primarily in the early stages when weeds are small in stature. But if they are aggressive weeds with strong taproots, such as dandelions and buckhorn plantain, they can grow back very quickly.
Herbicides
- Organic. Always use certified products. “Don't make homemade herbicides. They are still pesticides and can be dangerous,” Gonçalves said. Corn gluten meal is the only organic pre-emergent herbicide. Organic herbicides are available for consumers in different combinations and concentrations. “Vinegar-based herbicides can be very expensive, but other options such as citric acid-based, caprylic acid-based, clove-oil-based, or ammonium nonanoate-based can be more affordable and provide vinegar-like weed control,” Gonçalves said.
- Synthetic. “Many synthetic herbicides also are available for consumers. But the question is: Do you need it? Keep in mind that, all options presented above must be considered first before deciding to use herbicides,” Gonçalves said.
- In both cases, synthetic and organic herbicides are pesticides. Carefully read and follow the label directions.
Learn more:
- Author: Jeannette Warnert
A collection of small raised beds decorated with colorful scarecrows, quaint décor and several rabbit topiaries make up Mr. McGregor's Garden, but this one doesn't have mischievous Peter Rabbit nibbling on the fruit and vegetables. The main problem appears to be snails. Last fall, dozens of garden snails were found feeding on the leaves of napa cabbage, cauliflower, kohlrabi and broccoli plants.
The Master Gardeners have been searching for organic solutions to the problem. Picking them off one by one has been the first line of defense. The Farmers Almanac suggests spreading crushed egg shells to deter snails from garden beds, and we tried it. However, the UC Integrated Pest Management program reports that egg shells are an ineffective deterrent, and we have seen little improvement.
Another solution available to Fresno County gardeners are decollate snails. Decollates are small, thin, tapered and easy to distinguish from the familiar larger, rounded brown garden snails. The decollate is native to North Africa and the Mediterranean region. It was accidentally introduced to Southern California in the 1960s, and has since helped manage snails in gardens and agricultural settings throughout Southern California and parts of the San Joaquin Valley. It is legal to purchase and release decollates only in the California counties of Fresno, Imperial, Kern, Los Angeles, Madera, Orange, Riverside, Santa Barbara, San Bernardino, San Diego, Tulare and Ventura. Because of its potential adverse impact on certain endangered and native mollusks, they should not be used in any other places in the state. Even in counties were decollate snails are permitted, they should not be introduced in or near natural areas because of the potential danger to native snails.
“Literature says it takes four to eight years for decollate snails to control brown snails, but my experience is they'll clean them out in a year,” Woods said.
The decollates are easy to find throughout Woods' front and back yards, under rocks and plants and nestled in plant litter. In February, Woods donated about 30 decollate snails to the Master Gardener's Children's Garden. The decollates were dispersed among strawberry and vegetable plants. While not a scientific trial, our experiment may lead to fewer snail and slug pests and less leaf damage in the coming years.
More information:
Visit the UC Master Gardeners Children's Garden in the Garden of the Sun, 1750 Winery Ave., Fresno. Hours: 9 to 11 a.m. Monday, Wednesday and Friday.
How to manage snails and slugs, UC IPM
UC IPM Natural Enemies Gallery, decollate snails
Identify snail damage, UC IPM (YouTube video)