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UC Marin Master Gardener Articles in the Marin Independent Journal

UC Marin Master Gardeners have contributed to the Marin Independent Journal's "Ask a Master Gardener" column every Saturday since 1999. We have a team of dedicated writers who have covered nearly every aspect of gardening for Marin County over the years. Search our archives below by category of interest, or use the search box to locate stories by year, month or specific subject.

 

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UC Marin Master Gardener Articles in the Marin Independent Journal

UC Marin Master Gardeners have contributed to the Marin Independent Journal's "Ask a Master Gardener" column every Saturday since 1999. We have a team of dedicated writers who have covered nearly every aspect of gardening for Marin County over the years. Search our archives below by category of interest, or use the search box to locate stories by year, month or specific subject.

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Seeing red? Boxelder bugs, our native neighbors

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adult boxedler bug
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cluster of boxelder nymphs, or juveniles
The Boxelder nymphs, or juveniles, are smaller than the adultsand lack wings, appearing bright red before developing black markings as they mature. Photo: Creative Commons 

If you’ve noticed clusters of red-and-black insects sunning themselves on your house lately, you’re not imagining things, those are probably Western boxelder bugs.

Most of us associate boxelder bugs with fall — when they suddenly blanket warm, west-facing walls and make it feel like your house is being swallowed. Fall is their most dramatic season. But it’s not the only time they show up.

Here in Marin, especially near creeks and mature maples, boxelder bugs can be seen on sunny walls in multiple seasons. What changes is the reason.

The Western boxelder bug (Boisea rubrolineata) is native to the western United States and has long been part of our local ecosystem. Adults are about half an inch long, black with thin red lines tracing the thorax and wings. The younger stages are bright red at first, gradually developing darker markings. They’re eye-catching, which is part of why they feel alarming.

mature boxelder tree growing along a roadside
The Boxelder is a common tree in Marin along creeks and seasonal waterways Photo: CK Kelly Creative Commons 

Their main food source is the boxelder tree (Acer negundo), a maple that thrives in riparian corridors. You’ll often see boxelder growing along Lagunitas Creek through Fairfax and San Geronimo Valley, along Corte Madera Creek as it winds through Ross and Kentfield, and beside Miller Creek and Novato Creek in the North Bay. They’re also common near Gallinas Creek, Arroyo Corte Madera del Presidio in Mill Valley, and other streamside areas where soils stay moist and deep.

Because these trees cluster along waterways and in older neighborhoods planted decades ago, homes nearby naturally see higher numbers of boxelder bugs. The insects feed mostly on seeds and sap. They may wander onto other maples, ash, or even fruit trees, but they rarely cause meaningful damage. Established trees typically tolerate them without issue.

So why are they on your house in March?

In fall, adults gather on warm, south- and west-facing walls as they prepare to overwinter. They’re looking for tiny cracks and gaps where they can shelter through colder months. That’s when we see the big aggregations — sometimes hundreds or thousands at once.

Over winter, many remain tucked into siding gaps, attic vents, or other protected spaces. Then, on warm late-winter and early-spring days — like the ones we’ve been having — they re-emerge and cluster on sunny surfaces to warm up. It’s essentially their version of stretching in the morning sun.

During summer, you’ll mostly find them near host trees, feeding and developing. So while fall is the main event, wall congregations aren’t strictly seasonal.

adult boxelder bug
The Boxedler bug is easily recognizable as an adult due to the three red lines on its thorax and the red veining on its wings Photo: Judy Gallagher Creative Commons 

The good news is that boxelder bugs are far more dramatic than destructive. They don’t bite, they don’t sting, they don’t transmit disease, and they don’t reproduce indoors. If they wander inside, it’s accidental — they’re just looking for shelter.

This is where a little Integrated Pest Management mindset really helps. Instead of reacting with sprays — which rarely solve the problem and can harm beneficial insects — it’s more effective to think about what the bugs are trying to do.

They’re looking for warmth and entry points.

If they’re getting inside your house, the long-term solution is sealing cracks around windows, doors, vents, siding seams, and utility lines. A careful afternoon with caulk can make a noticeable difference next season.

If they’re clustered outside, a strong stream of water will break up the group. It won’t eliminate them, but it disrupts the aggregation. Indoors, a vacuum works well. Crushing them isn’t recommended — they can stain surfaces, and they can stink.

Living in Marin means sharing space with a lot of wildlife, some more charming than others. Boxelder bugs may not win popularity contests, but they were here before we were. If they’re sunning themselves on your wall this week, take it as a sign that spring is warming up. And know that, with a few simple adjustments, you can keep the relationship manageable — even when fall brings the encore performance.

By James Campbell, March 28, 2026

UC Marin Master Gardeners

Pick a pepper and plant it!

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bags of harvested peppers and tomatoes
A savory, spicy and satisfying September harvest of Cayenne, Cherry, Jalapeño and Fresno peppers. Photo: Tom Yetter

A walk through any Marin market will reveal bins piled high with a dazzling array of peppers in many colors, shapes, and sizes. Those familiar market staples offer only a small sampling of the vast choices available to home gardeners eager to grow something new. Our fascination with peppers is the most recent chapter in a much longer story that began in the late 15th century, when European explorers stumbled upon thriving agricultural systems in the Americas that were already thousands of years old. Enthralled by their heat and flavor, explorers carried pepper seeds and plant materials back to the Old World. Five species of the plant genus Capsicum created an instant culinary sensation that went viral, quickly spreading worldwide. The genetic diversity that had begun thousands of years earlier expanded dramatically as peppers were bred by gardeners and adopted into cuisines across Africa, Asia, and Australia. Today, more than 6,000 commercially named varieties of peppers trace their ancestry to just five species native to Central and South America.

peppers growing on a bush
Serrano peppers add color and beauty to any garden or patio, and more than a touch of heat in the kitchen. Photo: Tom Yetter

Marin gardeners can share in this extraordinary story, and it’s not too late to begin a new chapter at home. Grown as annuals in Marin, peppers are considered a warm-season crop, and starting from seed is still possible, even in late March. Seed starting does require more planning, patience, and a bit of shopping. A recent visit to a local nursery revealed more than forty varieties on a single seed rack, while online sources offer hundreds more. The selection available from seed far exceeds the choices of seedlings that may later appear at garden centers. Seeds selected from local garden centers or California-based seed companies often carry an added advantage: they have been chosen with regional conditions in mind, giving them a strong likelihood of success in Marin’s diverse gardens. California Wonder, Early Jalapeño and Cherry Bomb F1 are among the many varieties chosen by the Marin Master Gardeners for our unique Mediterranean climate.

tray of multi colored peppers
Colorful peppers of all varieties continue to produce harvests late into November at home gardens and local markets in Marin. Photo: Terry Amerson

Peppers are slow to germinate. Even in a toasty greenhouse, and aided by gentle bottom heat and ideal light, moisture, and humidity it will take six to ten weeks before seedlings are ready to harden off and plant outdoors. Seeds planted in March can produce seedlings ready for the garden by May or early June. Everything is temperature dependent. After a week to 10 days of hardening, and once nighttime temperatures remain consistently above 55° F with daytime temps between 65 and 85°F, pepper seedlings can be planted outdoors. In warmer inland areas, this often occurs by mid to late April. In cooler, coastal, or fog-influenced gardens, transplanting may need to wait until May. Many early varieties recommended for Marin will begin producing 60 to 70 days after planting, with harvests beginning in late summer and continuing into October or even November. 

Garden site selection can also be critical. Peppers will thrive in the warmest, sunniest spot you can provide. They should never be planted where tomatoes, potatoes, or eggplants have been grown within the past three years, allowing soil time to clear pests and pathogens common to these nightshade relatives. For this reason, many gardeners grow peppers in containers or fabric grow bags filled with sterile potting soil. A well-hydrated five-gallon grow bag will weigh between 25 and 30 pounds, making it possible to move plants to safety during cold snaps or storms while providing stability. Peppers will need support once fruiting begins. A simple stake or cage works well. While smaller containers will still produce a modest harvest, larger pots generally yield more peppers.

Growing peppers in Marin County is more than simply producing a beautiful and tasty harvest. It is a chance to take part in an ancient culinary and gardening tradition, adapted to our unique climate and landscapes. Each pepper grown here links a modern home garden to thousands of years of human curiosity, selection, and exchange, an enduring story that continues to grow, one plant at a time.

By Terry Amerson, March 21, 2026

UC Marin Master Gardeners

Sweet peas grown with ease

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Nostalgic and timeless, the first blooms of sweet peas (Lathyrus odoratus) are a springtime treat. Bearing a heavenly floral scent and coming in every color except yellow, it’s easy to see why gardeners around the world fall in love with sweet peas. Additionally, they are relatively easy to start from seed; there are a few tricks to growing them in our summer-dry Mediterranean climate, but with the right care, even beginner gardeners can enjoy a row of fragrant sweet peas come spring!

sweet pea seedlings
These sweet pea seedlings are still too small to be planted out. Photo: Emily Daane

Sweet peas are hardy annuals, meaning that they can tolerate low temperatures - in our mild climate, they can be sown either in autumn or late winter. Seeds can be started early indoors by spreading seeds across a damp paper towel placed in the bottom of a container. Cover the container with plastic film and leave the seeds overnight: this will help soften the seed coat, leading to speedier germination. You can also leave the seeds in their container or in a plastic bag until they’ve begun to sprout – I’ve had the most success with this method. Once you’ve prepared your seeds and are ready to plant, choose seed trays or seedling pots with a depth of 4 inches or greater to give their roots ample room, and cover seeds with half an inch of soil. It’s best not to directly sow the seeds where you intend your sweet pea to go, as this can leave young seedlings vulnerable to being munched on by pests. After the seedlings have reached at least 3 inches in height, they can be planted out in the garden. 

sweet peas spilling over a pot
It’s important to build a tall, sturdy structure - here, my too-flimsy structure collapsed under the sweet peas’ weight. Photo: Emily Daane

Sweet pea plants produce vines that can reach 5-7 feet in height, so it’s important to provide the plants with a trellis or structure to climb up: examples include wire fencing or netting run between two stakes, or you can make a tripod of stakes wrapped in twine. Or, you can choose a dwarf or bush variety (for example, the ‘Supersnoop’ series) that only reaches 8 inches to 3 feet in height and does not need staking. Prepare your planting site by adding compost and a natural fertilizer, such as bone meal or a well-balanced organic fertilizer, to the soil. Sweet peas thrive with their roots in cool, moist soil and their vines in full sun: to achieve this, you can plant annuals around the base of your sweet pea to shade the roots. It’s also a good idea to pinch, or remove, the growing tip of your sweet peas, taking them down to a pair of leaf nodes once they’ve reached 4-6 inches in height, as this increases the number of side shoots – and therefore blooms – your sweet peas produce.  

closeup of sweet peas in a jar
A posy of sweet peas: this white variety ‘Jilly’ is exceptionally scented even among sweet peas. Photo: Emily Daane

Sweet peas prefer cooler weather – in our climate, they’re likely to bloom from mid-spring until early summer, when it becomes too warm for them. However, for the months in which sweet peas bloom, they bloom prolifically. While a few sweet pea vines growing up a trellis make a stunning decoration for any garden, one of the reasons I grow them is that they make remarkable cut flowers. Sweet peas actually benefit from having their blooms cut, so the more you cut them, the more they bloom. If left alone, sweet pea blossoms eventually form green pods that resemble peas. However, it’s important not to get the two confused, as unlike their edible cousins, sweet peas are poisonous if eaten in quantity. If left to ripen, sweet pea pods form new sweet pea seeds – to collect them, just open up the pods once they’ve dried out, and hold onto the seeds until it’s time to plant them next growing season. Keep in mind that seeds may not produce plants that are the same color as the parent plant.

With their sweet fragrance and delicate blooms, sweet peas are sure to delight. So plant a row of sweet peas this spring to fill your garden with scent and your heart with whimsy.

By Emily Daane, March 14 2026

UC Marin Master Gardeners

Discover the hover fly

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Hover fly nectaring on rock purslane, Calendrinia grandiflora
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A hoverfly hovering seemingly motionless in mid-air over a flower
This hoverfly is performing the act it is named for, hovering, seemingly motionless in mid-air over a flower. Photo: UC Regents

Last summer, I watched bee-looking creatures flying in zigzag formation, each with a separate flight plan. Are those bumble bees?  Wasps? Nope, they were hover flies, also called syrphid flies, drone flies, and flower flies.  Although they look like bees, they are a type of fly engaging in Batesian mimicry, a type of identity theft which is done to fool predators. To tell whether it’s a fly or a bee, a closer look shows hoverflies look different from bees because the fly has short, stubby antennae, two wings, not four, and no stinger.

They can be as small as 1/8 inch long and may be brightly colored with spots, stripes, or bands of yellow and brown or black. Colors vary depending on temperature during pupation, with the higher the temperature, the more yellow, while lower temperatures produce adults with darker markings.

A quick way to tell whether a hoverfly is a female or male is by its eyes. Males’ eyes are located together, and females’ eyes are set apart.

The larvae eat a variety of foods. Some devour aphids, thrips, and other leaf-hoppers. Other hoverfly larvae eat decaying plant or animal matter. The species that includes the drone fly, Eristalis tenax, lives in stagnant water in ponds, streams, or sewage as a larva but not as an adult. 

hover fly appearing like bumble bee
This hover fly is engaging in identity theft by pretending to be a bumble bee. Photo: Kathy Keatly Garvey

There are 6000 hoverfly species and 200 genera worldwide, including in California gardens. Most of the species are in the genus inquilines, a group that lays their eggs in bumblebee and wasp nests so their larvae can consume the host larvae. Other species lay their eggs in aphid colonies for their larvae’s food.

The hovering behavior of hoverflies is not like hummingbirds who hover while feeding, but is one way of finding a food source. For male hoverflies, it may be a territorial display while seeking females. The female uses hovering to search for a place to deposit her eggs.

Hover flies are important to a healthy garden for two reasons: they are impressive pollinators and they are pest-eating parasitoids. The adults feed on nectar and pollen, but their larvae feed on a variety of foods. Compared to honeybees, they take second place in pollinating plants. One reason is that bees are hairier and their hair collects more pollen, but hover flies have more motivation. They visit more flowers within a field, starting earlier in the day before it warms up and work in poor weather conditions.

Hover fly migration is an advantage to plants by exporting pollen and bringing a variety of pollen back into the area. Hoverflies can carry an average of pollen from many different plant species back boosting the genetic variety of crops. 

Hover fly nectaring on rock purslane, Calendrinia grandiflora
Hover fly nectaring on rock purslane, Calendrinia grandiflora. Photo: UC Regents

A flower can be pollinated by both bees and hoverflies ensuring pollination is more complete with more seeds and improved quality of fruit. 

Organic farmers have learned that an aphid on a head of lettuce is doomed if a hoverfly larvae is nearby. Lab experiments show that a single marmalade fly can devour up to 400 aphids during the time it is developing. There are predatory hoverfly larvae that farmers can buy for natural pest control. 

The larvae that feed on dead wood or rotting plants have the potential of cleaning up sewage.by decomposing organic matter or filtering bacteria and fungi from freshwater 

As with bees, the number of hoverflies is decreasing. Reasons for the decreasing rate and risk of extinction are much the same for both: pollution, pesticides, and degradation of habitats. Hoverflies need more than flowers for nectar and pollen; and many species also need compost heaps and rotting wood for their larvae.

Gardeners can help the larvae of these beneficial creatures by adding an old decaying log to the flower bed or planting the seeds of wildflowers that hoverflies like. Hoverflies like umbrella–shaped members of the parsley family like dill, cow parsnips, and Queen Ann’s lace. 

By Sara O’Keefe, March 7 2026

UC Marin Master Gardeners

A message from local pollinators

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The Marin Master Gardeners are always talking about pollinators and how important they are as essential to food security and healthy ecosystems. More than 80 percent of the world's flowering plants depend on pollinators for reproduction, including many wildflowers and other important native plant species.

Without the diversity of plant life that pollinators help support, our air, soil, and water quality can all suffer. While wind, rain, birds, and bats are active pollinators, the real workhorses are bugs like bees, wasps, butterflies, flies, and beetles.

Just like us humans, pollinators have their favorite dining sources that provide what they need visually and structurally.

Multiple pollinators on a poppy
Multiple pollinators working together. Photo: UCNR Repository
  • Honeybees are the ones we know best, but there are approximately 3,600 bee species native to the United States.  Ninety percent of these bee species are solitary, meaning that they the females build and provide for their own nests.  All our bee friends possess hairs and other anatomical structures that are equipped to collect and transport their pollen load. Bees stalk brightly colored flowers with a sweet scent that they can walk on to sip nectar
  • Bumble bees are recognized by their round, fuzzy black bodies.  They operate a little differently by performing buzz pollination, which involves grasping a flower with their jaws and dislodging the pollen by vibrating their wing muscles.  Many wildflowers and backyard crops like tomatoes and peppers benefit from buzz pollination.
  • We all know the beloved monarch butterfly, but there are many other species of butterflies and moths that are important to the pollination scene. Some of the species are generalists and not too picky about the plants they visit, but others of the species have specific habitat needs. Butterflies and moths need a place to land when they visit, so they prefer flowers with broad, flat faces.  Then they use their straw-like mouth parts to suck the nectar from deep inside.
  • Hummingbirds have long beaks and brush-like tongues for digging deep into a flower for its pollen.  They are also attracted to bright colors, especially red.
  • The fly is second only to bees for their importance as a pollinator.  They are more adaptable to rough weather conditions when bees won’t head out.  They are kind of accidental pollinators because they collect pollen while feeding on nectar.  Flies are also willing to visit putrid or foul-smelling plants that others won’t pay any attention to.

Every gardener can make a difference by attracting and nurturing pollinators in their yards. 

Monarch butterfly on a zinnia
A Monarch butterfly is beautiful and an important pollinator. Photo: Flickr, Peter Miller
  • Provide flowers in a variety of different colors and shapes to attract any pollinator in your hood.
  • Provide as much continuous bloom as possible.  It is pretty easy to do from spring to fall, but try to provide choices in winter for those pollinators that do not migrate.
  • By practicing Integrated Pest Management (IPM), you protect pollinators from chemicals destructive to their food choices and their well-being.
  • Provide water sources by placing birdbaths or saucers on the ground. Pollinators also drink from puddles and any moisture on leaves.
  • Prioritize native species like Milkweed, Poppies, and Asters for your local pollinators. 

The Marin Master Gardeners are here to help you!  Besides all the information you can find about pollinators on our website and in our quarterly newsletter, the Leaflet, we are hosting a Pollinator Plant sale on Saturday, March 7, 9 AM to 12 PM outside the Falkirk Green House in San Rafael.  Thirty-five plus varieties of pollinators are being grown organically in the greenhouse now, including literally five hundred Narrow Leaf Milkweed to feed hungry, hungry monarch caterpillars. Many native plants will be available to help the native pollinators.  “Bug Hotels” will be available to purchase for the kiddos to decorate.  Learn more at https://youtu.be/OmdGkEnUwlg 

By Dot Zanotti Ingels, February 28, 2026

UC Marin Master Gardeners

Winter gardening tips for Marin County

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February in Marin County holds a quiet kind of magic. The days become noticeably longer and a bit warmer. The hills are still emerald as the winter rain and air carry a crisp brightness between storms, and although the garden is seemingly asleep, it is humming below the surface. For gardeners in our county, this is a pivotal month. The groundwork for spring’s abundance begins now in the soft soil of late winter.

Here are some of the essential winter tasks to accomplish and get you back into your garden.

Take time to do bed preparation and cleanup

The winter rains create a softening of the soil and make it ideal for easier weed pulling. 

This is a good time to amend the garden and raised beds with organic compost. Layer it to replenish nutrients lost in the winter rains. Lightly mix it into the top 6-10 inches of in-ground soil or 2-3 inches in raised beds, or add organic mulch to the top of your soil where it will serve as an additional food source for soil life. 

It is time to cut down cover crops, if ready. Chop them into pieces and put them into your compost pile.

winter pruning a tree
February is a great time to do your fruit tree pruning, removing dead, diseased and crossing branches in order to open up the tree to sunlight and air. Photo: Vell, Envato Elements

Prune with purpose

For deciduous fruit trees, February is one of the last great opportunities for dormant pruning. Apples, plums, pears, persimmons, and plums all benefit from careful shaping before bud break. Removed dead, diseased, or dying branches or branches that are crossing. Remove any water sprouts. 

Opening the structure of the tree allows air and sunlight to move through the canopy. Pruning increases plant vigor, controls plant size, and can increase the yield of fruit, among many other benefits. Pruning can also reduce opportunities for fungal disease to grow in Marin’s coastal moist climate. For more detailed info on pruning, go to: https://ucanr.edu/ and search for “pruning”.

a hand planting seeds in the soil
February is a great time to plant cool season seeds directly in the amended soil. Photo: Yanadjana, Envato Elements

Plant your cool-season seeds and veggie starts

February marks the start of the early spring planting season for us in Marin. Sow seeds indoors for arugula, kale, onions, and peppers. Sow seeds outdoors for beets, carrots, chard, collard greens, leeks, lettuce, bunching onions, peas, potatoes, radish, spinach, and sunchokes. Transplant starts for bareroot artichokes, asparagus roots, fava beans, beets, broccoli, Brussel sprouts, cabbage, carrots, cauliflower, celery, chard, collard, kale, lettuce, leeks, onion starts, parsnip, peas, potatoes, radishes, rhubarb divisions, spinach, sunchoke tubers, Swiss chard, and turnip. For more detailed info on growing edibles, go to: https://ucanr.edu/ and search for “edibles”.

Plant hardy annual flowers

For a good, strong spring bloom, consider planting sweet peas, calendula, snapdragons, Iceland poppies, and larkspur. This will give enough time for roots to establish strong systems before warm weather hits.

Check for pests and fungus 

February can bring with it cool, damp weather, which can lead to early emergence of snails, slugs, aphids, and powdery mildew. Inspect plants regularly and hand-pick snails, and use non-toxic insecticidal soap spray or organic insecticidal oil to reduce aphids. Prune parts of plants with fungus and create better air circulation, which can reduce fungal infections.

Plan for garden changes and additions

February brings with it a good time to look over the “bones” of your garden –the overall appearance of your plant material, furniture placement, and garden ornaments. It is time to assess what changes could be made to improve how it looks and feels. What new plants might add some pizazz to your color story, what new natives might entice beneficial insects, bees, and birds to your property, and what plant removals are overdue due to overgrowth and would make your property Fire Safe. 

Check out UC Marin Master Gardeners YouTube channel for more ideas. 

Enjoy this month of preparation, promise and subtle transformation while you step outside, breathe the cool air again and begin afresh.

By Jill Fugaro, February 21, 2026

UC Marin Master Gardeners

Waging war on weeds: start early, weed often, know your enemy.

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Weeds are the troublemakers in your garden. There they are, lurking among the flowers, persisting, and interfering with your plans for a California native garden or a pollinator paradise. Weeds compete aggressively with desirable plants for water, nutrients, and sunlight. Invasive species threaten ecosystems, harm wildlife, and disrupt our water supply.

The key to eradication is to learn as much as possible about these garden enemies. Marin Master Gardeners can help identify weeds and create a management plan. The UC Statewide Integrated Pest Management Program Home / UC Statewide IPM Program (UC IPM) has many useful features, including the Weed Photo Gallery--UC IPM, which contains hundreds of images and management tips for more than 150 common California weeds.

The goal of weed management is to use the least harmful method for people and the environment—and to apply it at the right time. Cultural controls include site preparation, soil testing, and irrigation management. Mechanical or physical controls range from hoeing and hand-pulling to mulching or soil solarization (covering soil with clear or black plastic). Gardeners have specialized tools available, like the weed fork and the push-pull hoe (also called a hula hoe) that cuts in both directions. The weed wrench is a back-saving device that levers broom plants out of the ground. Perennial weeds may take several years to bring under control. Chemical herbicides are always a last resort.

Here are four troublesome invaders that plague my garden. They thrive on neglect and reward persistent control.

morning glory look-alike, field bindweed
Field Bindweed looks like a morning-glory but twists to strangle other plants. Photo: Michelle Wiesbrook, University of Illinois

Field bindweed (Convolvulus arvensis)
This nemesis was already lurking on the front bank when I moved here many years ago. Roots can extend up to 20 feet deep, and seeds can live for 60 years. Its white morning-glory-like flowers seem innocent, but the word “field” in its name hints that it can take over entire landscapes. Bindweed entwines around other plants, and each tiny piece of root left behind can produce a new plant. Persistent hand pulling is essential. Tilling the soil will only spread the fragments. When soil is moist, loosen it with a fork and patiently remove entire roots. In severe infestations, mulching with black plastic for several months can help smother the root system but complete death under mulch takes more than 3 years.  Prevent flowering so seeds—viable for decades—never form.

Bermuda buttercup
Bermuda buttercup produces bright yellow flowers in the Spring and spreads into a dense mat with underground bulbs. Photo: Creative Commons

Bermuda buttercup (Oxalis pes-caprae)
This bright yellow spring bloomer, originally from South Africa, has spread throughout California. It develops from underground bulbs and forms dense mats. Gophers and voles enjoy the bulbs and help disperse them. When hand-pulling, remove the entire plant, including rhizomes and bulbs. Removing tops prior to flowering also helps.  A thick layer of mulch may smother young plants before they emerge.


 

Petty spurge
Petty Spurge produces a milky sap that irritates the skin. Hand-pull the weeds before they go to seed. Photo: Alice Cason

Petty spurge (Euphorbia peplus)
This winter or summer annual fills bare spaces with leafy green plants and inconspicuous flowers. Like all spurges, it produces a milky sap, which can be irritating or toxic. Fortunately, petty spurge and other annual Euphorbia species are easily controlled by manual removal before they set seed.

 



 

Bristly oxtongue
Bristly oxtongue has a yellow flower that looks like a dandelion and sprouts quickly to 3 feet tall. Photo: Alice Cason

Bristly oxtongue (Helminthotheca echioides)
Native to the Mediterranean region, this winter or summer annual (sometimes biennial) is widespread in California. It can grow over three feet tall with sprawling stems and leaves covered in bristly hairs giving a warty appearance. The yellow, dandelion-like flowers produce seeds that disperse far on the wind. Hand pulling is effective, especially when the weed is still in its basal rosette stage.

The Marin–Sonoma Weed Management Association monitors invasive weeds throughout the North Bay and evaluates the risk from each species. There is even a Japanese knotweed action team working to remove current infestations and prevent further spread.

Remember to weed when the soil is moist to avoid disturbing the soil structure. Mulch with organic materials right after weeding to suppress new growth. Avoid chemicals and herbicides whenever possible. Hand weeding, mulching, and the use of cover crops are science-based, earth-friendly ways to manage weeds.

By Alice Cason, February 14, 2026

UC Marin Master Gardeners

Backyard fruit

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Native grape, Vitis californica, growing on a vine
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Native grape, Vitis californica, growing on a vine
Vitis californica, our native grape, grows well on fences and provides fall color. Photo: Anne-Marie Walker 

Fruits bring year-round interest to your garden as well as a sense of achievement gained by growing and harvesting your own fruit. My husband says growing blueberries is reason enough to grow backyard fruit. Yet, here’s a little secret. Marin’s favorable Mediterranean climate allows growing so much more and the possibilities proliferate when you plant vertically and in containers to enjoy the pleasure of eating fruit grown in your own backyard.

It's winter now and most gardens support a lemon tree, facilitating the enjoyment of tree-ripened lemons. There are so many more varieties of citrus ripening now and producing tantalizing and seductive fruit such as kumquats, Kishu tangerines, and blood oranges. Citrus thrive in containers in a sunny spot with not too much wind. My citrus trees thrive on a hill where once there was a lawn. I planted herbs under the trees to confuse ants which can bring scale to citrus trees. Another fruit to plant in winter is strawberries. In Marin, the variety ‘Seascape’ does well planted in containers in a sunny spot. Be sure to plant in soil that drains well because strawberries are susceptible to root rot. They need plenty of slow-release nitrogen fertilizer, and if you cut off developing runners, berry production increases.

service berry blondies
Service berries make tasty berry blondies. Photo: Anne-Marie Walker

As winter begins to fade, the first sign of approaching spring is the glorious, showy bloom of fruit trees. Growing up on our ranch in Cloverdale, my sister snapped a photo of our parents sitting under flowering fruit trees. Spring is the time to plant fruit trees. Things to consider as you select which fruits to grow include what you like to eat, what will flourish best in your climate and what varieties of fruits afford ease of care and harvest. Selecting dwarf varieties can save lots of pruning time and permit higher density planting. Learn more at the California Rare Fruit Growers website and read the online UCANR PDF “The Backyard Orchard” which includes lots of information on growing fruits in your backyard. 

Late spring and early summer herald the start of berry season. In my garden, blueberries planted in the ground, form a hedge with more planted in containers on a terrace. The blueberry harvest season lasts about 4 months, from April to July. Other berries ripen later, including native specimens, Amalanchier, also known as serviceberry and huckleberry. These all grow beautifully in our Marin gardens, and while the berries are smaller, one can still make tasty treats like serviceberry blondies.   

Marin garden planted with apple, pomegranate, fig, and quince trees
Marin garden with apple, pomegranate, fig, and quince trees underplanted with herbs, lettuces and flowers. Photo: Anne-Marie Walker 

Fall arrives with yet another bounty of fruits you can enjoy from your backyard including apples, pears, figs, grapes, quinces, pomegranates, and persimmons. Selection must consider chill hours required for fruit production. In northern Marin, apples and pears flourish, while in southern Marin, pomegranates and figs may thrive better. Also ripe now are grapes whose vines happily twine along a fence, using vertical space to produce yet more backyard fruit. The leaves of grapes, also edible, make tender bites stuffed with rice, fish, and cheese and grilled. Remember the concord grape jelly your grandmother made from her backyard harvest? Backyard grapes, including our native grape Vitis californica, are perfect for spritzers or a verjus for salad dressing, the French word for fresh juice. The grapes can also be poached and added to fruit medleys, muffins and served with soft cheeses for charcuterie boards. 

Part of the reason I enjoy growing backyard fruit is the novelty aspect. I like tasting a variety not always found in markets. For example, markets abound with ‘Black Mission’ and ‘Brown Turkey’ figs. But where in the market can you find a ‘Genoa’ fig or a ‘Violette de Bordeaux’ fig? Figs ripen only on the tree. Specimens of backyard fruit will abound in nurseries soon. Consider the pleasures of growing fruit in your backyard and delight in the bounty as you harvest ripe fruits.

By Anne-Marie Walker, February 7, 2026

UC Marin Master Gardeners

Birds in the garden… how wonderful

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ruby-crowned kinglet
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A wren nest perched in a trellis
A wren nest perched in a trellis. Photo: Diane Lynch

I can think of nothing more endearing than seeing birds in my garden, unless it’s my dogs. Birds are some of the most interesting, varied, and resourceful creatures on earth, and they get a bum rap on intelligence sometimes. 

Bewick’s Wrens nest around my garden, from my trellises to my neighbor’s acacia jungle, and sometimes even in the little bird houses.  The babies gather on my deck to play and test out their wings.  As bug eaters, they must enjoy the insect bounty of the large native toyon (Heteromeles arbutifolia), which produces tasty red berries.  Since I’m not a tidy gardener, there are always lots of spider webs around to supply insect eaters. 

I have a palm tree, likely a Mexican Fan Palm (Washingtonia robusta), that’s grown from under six feet when I moved here 28 years ago to very tall today.  It should really be removed, but it harbors so much life that I resist culling it.  Hooded Orioles have nested in their dead fronds, until the crows stole their babies one spring and they moved to safer housing nearby…I hate the food chain at times like this. 

Scrub jay in a tree
Scrub jays are among the best distributors of acorns, which they cache for food but which also grow more oaks, one of our most important trees. Photo: Diane Lynch

I don’t see mockingbirds in my garden, but there’s one who greets me around the corner where it lives in the cotoneaster, pyracantha, ivy, and echium copse.   It likely has cozy nesting spots in the shelter of these invasive plants.  If you’re wondering who’s singing at o’dark thirty, it would be the mockingbird.

There are a couple of crows in the neighborhood who patrol, looking for mischief…  they’re omnivores and among our smartest birds…I saw a crow funeral one time, though scientists surmise that it’s a way for them to learn about potential threats.  Scrub Jays are also in the corvid family, and they’re great acorn planters, helping to distribute new oaks within a large radius of each tree.  It took me a while to figure out who was planting acorns in my pots around the garden…perfectly planted with a nice taproot.  

Flocks of Cedar Waxwings, charming little songbirds with a black mask and waxy red wingtips, show up for the fall berry crop.  I used to see them roost by the hundreds in a neighbor’s large elm tree, but lately I only see their flocks flying throughout the neighborhood.  If you’re lucky enough to have a madrone tree (Arbutus menziesii) they might come to your garden to eat the red berries, though other berries appeal to them as well. 

ruby-crowned kinglet
The ruby-crowned kinglet will sometimes show you his beautiful ruby crown. Photo: Diane Lynch

You might attract quail by creating some brush piles to protect these ground-dwellers from predators and to provide food. These days, I only occasionally see a few in my neighborhood, though they were common not so long ago. 

Hummingbirds are ubiquitous in many gardens, especially those with tubular red flowers such as fuchsias or our native California fuchsia (Epilobium canum).  Manzanita (Arctostaphylos sp.) flowers, native black sage (Salvia mellifera), sticky monkey (Mimulus aurantiacus & cardinalis), and hummingbird sage (S. spathacea) are all favored. The list goes on.  The Anna’s Hummingbird is here year-round, the Allen’s is a summer resident, and the Rufous migrates through western states from Alaska to Mexico.  These bold little birds are so much fun to watch and make getting outside to work a pleasure.  

Townsend’s warbler in a bush
The Townsend’s warbler shows up in my bottlebrush some winters. Photo: Diane Lynch

Some winters, a Townsend’s Warbler will hang out briefly in a bottlebrush tree (Callistemon spp.) outside my sunroom.  These tiny migratory birds eat primarily insects. Some years we get flocks of robins that gather in the stream-bed, along with their cousin, the Varied Thrush.  I hear Great Horned Owls at night… they are part of the rat patrol along with other raptors.  The Ruby Crown Kinglet appears every so often and puffs up his ruby crown for me to see. 

Consider planting some berry-producing plants, especially natives such as toyon, one of the best habitat plants to attract birds to your garden. Cultivars are available with red or yellow berries. 

By Diane Lynch, January 31, 2026

UC Marin Master Gardeners

Beyond the honeybee: pollinators for plants and people

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Anna's Hummingbird
Hummingbirds gather pollen on their beaks and foreheads while sipping nectar. Photo: Flickr, Robin Gwen Agarwal

Although we’re in the middle of winter, soon we’ll witness the unveiling of springtime and all her joyous colors: brilliant orange poppies, deep purple iris, and vivid yellow tidy tips. And after that beguiling display, we can look forward to summer’s velvety sages and rugged buckwheats. 

Ever wondered how these flowers keep showing up year after year? There’s no garden center in the wild. No mail order catalog. No Johnny Appleseed. 

The answer? It varies, depending on whether they’re annuals or perennials, but behind it all is a tireless army of pollinators: hummingbirds, bees, butterflies, beetles, wasps, flies, bats, and more.

The work these tireless creatures perform is critical. Pollination accounts for 80% of the world’s flowering plants, including most of our food crops. Without pollination, the environment around us would collapse, and we humans would cease as a species because we rely on plants for food and oxygen. 

But don’t worry! The system has been working for at least 130 million years.

monarch
Butterflies like this monarch pollinate by picking up bits of pollen on their long, spindly legs as they flutter from flower to flower. Photo: Flickr, Martin LaBar

Pollination: how it works

Virtually every seed-bearing and cone-bearing plant requires pollination. Pollen, that yellow dust that makes you sneeze, bears a plant’s male sex cells. When a bee or other pollinator transfers that pollen from the male parts of a flower to the female parts of the same or another flower in the same species, pollination occurs – that is, fertile seeds are produced. 

When pollination occurs within the same flower, it’s called self-pollination. When it occurs between different flowers, it’s called cross-pollination. Cross-pollination is preferable because it produces more genetic diversity, which in turn makes a species more likely to survive by adapting to its changing surroundings. 

Pollination between two completely different species does not produce viable seeds because the genetic material is incompatible. In other words, a poppy and a pine tree aren’t going to cross-pollinate. However, pollination between two closely related species can sometimes produce a hybrid offspring that contains traits from both parents. For instance, a habanero and jalapeño pepper might cross to create a fiery hybrid. Or your daughter might have your nose and your spouse’s eyes. You know how it works. 

Native bumblebee
Native bumblebees’ fuzzy bodies can carry more pollen than honeybees, fly in cooler and lower light conditions, and vibrate at a frequency that shakes pollen loose. Photo: Flickr, Robin Gwen Agarwal

Meet the pollinators

The first pollinator that probably comes to mind is the honeybee, the pervasive European insect introduced to California in 1853. Honeybees pollinate many California crops and are actually classified as domesticated livestock like sheep and goats. Although honeybees are helpful on the farm, they aren’t necessarily good for the environment. Why? Because they’ve roamed far beyond the farm, which affects our native bees. California has 1,600 native bee species, and honeybees can transmit diseases and often out-compete them for food. In addition, native bees are better pollinators and they also pollinate the native plants that are critical to our biodiversity. 

Hummingbirds, on the other hand, are always welcome pollinators. These beloved birds gather pollen on their beaks and foreheads while sipping nectar, and they have the added benefit of being able to hover over flowers for easy access. Hummingbirds appreciate tubular flowers that are red or orange. 

Butterflies are lovely pollinators, but they aren’t as efficient as bees at moving pollen. They pick up a bit of pollen on their long, spindly legs as they flutter from flower to flower. They have good vision but a weak sense of smell. Butterflies appreciate flowers in clusters, which provide landing pads. 

They may not be as alluring as butterflies, but flies, gnats, and even mosquitos are also worthy pollinators. Like chocolate? You can thank a small midge fly, the sole pollinator of the cocoa plant. 

Beetles were among the first insects that visited flowers and they remain important pollinators for ancient species like magnolias. They eat their way through plant parts and prefer flowers that are white or greenish, sweet-smelling, and bowl-shaped. 

Bats, the only flying mammals, pollinate over 300 species of fruit, including bananas and mangoes. They also pollinate agave, which is used for tequila. Margarita, anyone? 

By Marie Narlock, January 24, 2026

UC Marin Master Gardeners

Source URL: https://ucanr.edu/site/uc-marin-master-gardeners/ij-archive