Over the last few months, I've noticed lots of dry leaves and dieback of the top branches of one of my favorite red maples. The tree was here when we bought the property about eight years ago, so I don't know the exact cultivar or how it was planted.
There are a couple of common issues that might be to blame for the recent dieback. A normal, healthy root system grows away from a tree's stem, rather like spokes on a wheel. Trees grown in containers can become pot bound, forcing roots to grow in a circular pattern around the root ball, rather like a ball of string. These girdling roots cause compression of the stem and sapwood. If the roots aren't unwound, straightened out and properly trimmed when planted, the roots will become tighter and tighter as the tree grows.
This can also occur when trees are planted too deep, as adventitious (growing sideways from the stem) roots grow against the stem and squeeze the sapwood. This compression severely slows or stops the flow of water, nutrients, and food. Over time, it will choke the life from the tree.
If detected early, it is possible to cut away the girdling roots, allowing the tree to recover and thrive. But I dug down several inches to inspect the root ball and found no evidence of girdling roots.
Another common cause of dieback is verticillium wilt, a soil-borne fungal disease that enters the plant through the roots and shuts down the tree's ability to receive water. The tree will attempt to compartmentalize the fungus to keep it from spreading. You may see flagging, which is partial or total defoliation on one side of the tree. The tree will survive if it is successful in containing the fungus, but often the fungus will move throughout the tree and saving it won't be possible.
Signs of infection include reduced vigor, undersized, discolored, curling and drying leaves, and branch dieback. Peeling back or slicing into the infected bark often reveals a discolored, darkened area, which my tree doesn't have. However, the only way to be completely sure it isn't verticillium wilt is to have a sample tested at a diagnostic lab.
Unfortunately, another common cause of dying maples is simply lack of water. Japanese maples prefer the climate of their native homeland, where they commonly receive year-round rain, fog, and moisture. Although my tree survived the recent, lengthy drought, it appears that it may have thoroughly stressed the tree.
An arborist helped me inspect and diagnose my maple, and decide on the best course of action: Increase the amount of water it's getting, wait until cooler weather sets in to prune away damaged branches, and keep our fingers crossed.
By UC Master Gardener Rebecca Jepsen
This article first appeared in the September 1, 2019 print issue of the San Jose Mercury News.
Of course, we were wowed by all the incredible plants from around the world that we got to see, but we were especially excited about the snakes!
I know you may not want to adopt a pet snake — although many people do — but they are extremely beneficial to have slithering around your garden and landscape. Snakes prey on mice, rats, moles, voles, lizards, frogs, slugs, and even other snakes.
More than 30 species of snakes make the Bay Area home. Of those, only rattlesnakes are venomous to humans.
The Pacific gopher snake is the most common snake in Northern California and is often mistaken for a rattler. It is generally brown or tan with dark gray, black or brown spots along the length of its body. Adults are 4 to 5 feet long.
This snake is diurnal, meaning it hunts during the day and sleeps at night. It is found in woodlands, grasslands, chaparral, agricultural and riparian areas from sea level to the mountain ranges. If threatened it will flatten out its body and shake its tail. Although it has no rattle, the movement against dry grass can mimic the sound of a rattlesnake.
The Northern Pacific rattlesnake can range in color from olive to brown to black. It has dark brown and tan blotches along its body and medium to dark bars at the tail. Adults are typically 3 to 4 feet long.
Usual habitats include seaside dunes, rocky hillsides, woodlands, grasslands, and sometimes residential landscapes. You will often find them on hiking trails or bike paths, soaking up the sun.
A rattlesnake has a triangular head and a relatively thin neck. The body is thick, dull and non-glossy. A gopher snake's head is more pointy and just a bit bigger than its neck. It has a slender, glossy body and a pointed tail.
King snakes are extremely common throughout California. They are either black or dark brown with light striped bands circling their bodies. Adults are generally 3 to 4 feet long.
They can be found in nearly all habitats — forests, woodlands, grasslands, wetlands, and even the desert. They have been known to eat rattlesnakes as they are immune to the venom.
The Northern Rubber Boa is usually a fairly solid shade of brown, tan, pink or olive green. It has small, smooth scales and looks, well, very much like rubber. It only grows to about 2 feet in length.
Although Boas are very common, they are generally nocturnal so you may not see them. They are often found in meadows, grasslands, chaparral, and deciduous and coniferous forests.
Pacific Ring-necked snakes are beautiful small, thin, smooth-scaled snakes. They are black, gray or dark olive green with vivid orange rings around their necks. The underside is bright yellow or orange with black specks. They only grow to about 3 feet long and will coil their tails (showing off their bright colors) when threatened.
They like moist habitats such as wet meadows, gardens, farmland or forests. They eat insects, worms, lizards, salamanders, and tadpoles.
Other common snakes you may find while out hiking, biking or even hanging out in your backyard are Night snakes, Striped Racers, Sharp-tailed snakes, and many others.
You may not learn to love your snakes, but please learn to appreciate and respect them. They really are quite good at taking care of the rodents that are wrecking your lawn and eating your tomatoes!
By UC Master Gardener Rebecca Jepsen
This article first appeared in the June 16, 2019 issue of the San Jose Mercury News.
White grubs are the larvae of several species of scarab beetles. They are weird, kind of alien-looking little creatures that curl up into a C-shape when disturbed. They tend to grow to around 1-inch long, but some species can get much larger.
I have three raised beds in my garden area and replant them every spring and fall.
For the last couple of years, I have found an unusually large population of what I believe is a kind of grub called Cyclocphala, or masked chafers. The larvae have brown heads and legs and have dark stripes across their backs. The adults (beetles) are golden-brown and have an almost armor-like, shiny coating on them.
“It is not possible to identify these grubs without looking closely at features such as mouthparts and small hairs (called setae) located on their bodies,” said Karey Windbiel-Rojas, with the University of California Statewide Integrated Pest Management Program.
“However, they are the larvae of scarab beetles, and based on where you found them, they could be masked chafers, green fruit beetles, or something similar. What they are very likely NOT are Japanese beetle larvae, since those are more or less non-existent in California.”
Handpicking grubs from raised beds (as I do) and containers can be all the control needed. I have had no noticeable plant damage in my beds.
If you or a neighbor have chickens, they absolutely love grubs and will be overjoyed to help you cut down the population.
Grubs can, however, do major damage to turfgrass. Most damage occurs during late summer or early fall. You will see patches of brown, drying lawn in the infested areas.
Additional damage is often done by moles, voles, birds or skunks that are digging in the grass to feed on the grubs.
Before taking any control measures, dig around the root level of the grass to confirm that in fact the damage is caused by grubs. If you find more than six grubs per square foot, you may want to take action.
Since grubs feed close to the surface, aerating the soil can kill significant numbers of them.
Nematodes (tiny, microscopic roundworms) can also be applied to control grubs. They should be applied when the grubs are young and not overpopulated.
It is best to do so in late summer or early fall. A second application is highly recommended. Be sure to do your research about the proper way to prepare and apply nematodes for grub control.
If these natural measures don't work, it is important to know what kind of grub (or any other kind of pest) you have before deciding to use chemical control.
Get advice about the right chemical to use and the right amount necessary to get the job done. A wrong decision can mean wiping out other species.
You can take a grub (or another pest) specimen into your local Master Gardener office to get information about what to do.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the May 19, 2019 issue of the San Jose Mercury News.
This is the time of year you might spot the beautiful, majestic dance of the honeybees
Most swarming activity takes place from April through May. Bees don't swarm during the rain, so this year we will most likely see the time frame pushed back a few weeks.
Honey bees, Apis mellifera, swarm for one of two reasons. Either the hive has become too crowded so they split into two groups (or more), with one group remaining in the existing hive. Or they abscond. In this case, all bees including the queen abandon the existing hive completely due to lack of food or water, parasite or disease infestation, frequent disturbance by humans or animals, weather changes, poor ventilation, or problems with the queen.
Western honey bees aren't nearly as likely to abscond as African honey bees, (a hybrid of South American and European bees known as Africanized honey bees), which tend to swarm more and be a bit more defensive as well.
Worker bees are able to detect when it's time to swarm due to overcrowding of the hive or the lack of pheromone production from the queen. In preparation for the swarm, the workers will deprive the queen of food in order to slim her down so she can fly. They will also agitate and run her around in order to prevent her from laying many eggs. If they are going to swarm, they will create new queen cells and allow the queen to lay eggs so a new queen can emerge and take over the hive.
Besides making honey, honey bees are essential for pollinating approximately 90 percent of our crops globally. Many of our favorite foods like almonds, most of our cherries, apples, blueberries, and other fruit and nut crops wouldn't exist without these hard-working bees.
According to Deb Conway with GirlzWurk in Saratoga, “Honey bees aren't usually a problem, as they normally set up their hives in tree cavities, shrubs, light poles, or abandoned buildings. However, they can become a nuisance when they take up residence in the walls of your home, garden shed or in your water meter.”
That's when it's time to call someone like Deb who can come and rescue the hive.
Last year was a particularly bad year for honey bees. Some beekeepers reported up to a 90 percent loss in their hives in 2018. Causes for this include varroa mite infestations, increased pathogens due to the warm weather, increased use of pesticides, and a decrease in diversity of food sources.
So, what can we do about a swarm? “If you leave the bees alone, they will leave you alone.,” said Dr. Elina L. Niño, a honey bee expert at UC Davis. “It only takes a few hours, or at most a day or two, for them to find and settle into their new home.”
Bees, as well as our other important and beneficial insects, are struggling. Our tendency to develop land and our extensive use of harmful chemicals are wiping out their natural habitat.
The public can truly make a difference by ceasing to use pesticides and by planting an array of beautiful, attractant plants such as ceanothus, lavender, echium, rosemary, penstemon and mint (mint is only recommended in containers because it is so invasive). For more bee-friendly plant ideas, visit UC Davis Häagen-Dazs Honey Bee Haven.
Let's all commit to creating safe and nurturing spaces in our backyards, gardens (and yes, even on those balconies and decks) where our much-needed pollinators and beneficial insects can not only survive, but thrive!
For help in relocating a swarm or hive, or to contact a local beekeeper, visit the Santa Clara Valley Beekeepers Guild, which has information about Santa Clara as well as surrounding counties.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the April 16, 2019 issue of the San Jose Mercury News./h3>
Tomatoes and pepper and herbs, oh my! Markets and tours will soon be popping up all around the Bay Area
The 25th annual Spring Garden Market brought to you by the Santa Clara Master Gardeners, will take place on April 13th, 9 a.m. to 2 p.m. in Martial Cottle Park, 5283 Snell Ave, San Jose. This year's event is being held in conjunction with the Park's Spring Celebration, which runs from 10 a.m. to 3 p.m.
The market is a fabulous, fun-filled, family event featuring tasty food, music, plant sales, gardening talks and tours throughout the day.
If you enjoy edible gardening or would like to learn, this truly is the event for you. Among the plants for sale will be 77 varieties of tomatoes from cherry and plum to classic and beefsteak, and 72 choices of peppers, from super sweet to fire-engine hot varieties.
If you haven't grown your own herb garden, we will have everything you need to get you growing. Growing herbs is a great project to start with your kids. Choose from 10 varieties of basil, and add in some chives, dill, oregano, fennel, lemongrass, even some chocolate mint.
This year our flower team has outdone themselves by seeding up more than 50 varieties of amaranth, celosia, cosmos, rudbeckia, salvia, sunflower, zinnia, and many other blooming beauties.
And, of course, we will have an amazing array of succulents. You can purchase individual plants to make your own creations or buy one of the gorgeous, pre-planted “works-of-art” that our succulent team has put together.
There will also be a number of educational talks on many topics such as container gardening, tomatoes, chiles and peppers, and how to grow succulents and native plants. Workshops will include how to care for and clean your garden tools, composting, controlling gophers and moles, and much, much more.
For more information visit the Master Gardener's website.
The Going Native Garden Tour 2019, now in its 17th year, will feature tours of more than 100 gardens from Morgan Hill to San Mateo showcasing California native plants. The North Bay tour is on May 4 and the South Bay tour is on May 5. Both run from 10 a.m. to 4 p.m. Visit the website for more information.
The Bringing Back the Natives Garden Tour will feature more than 30 native/Mediterranean gardens throughout Alameda and Contra Costa counties. The15th annual tour takes place May 5, 10 a.m. to 5 p.m. Some gardens will feature live music, artwork, native plants for sale and plenty of activities for the kids. Visit the website for more information.
The 10th annual Spring Garden Market of San Mateo and San Francisco counties, a plant sale and educational fair brought by the UCCE Master Gardeners of San Mateo and San Francisco Counties, is April 13, 9 a.m. to 1 p.m., San Mateo Events Center, 2495 South Delaware St., San Mateo. Visit the website for more information.
The 8th Annual Great Tomato Plant Sale will take place in three East Bay locations. Note that only cash or checks are accepted. Visit the website for more information.
- Central County Sale: Our Garden 2405 Shadelands Dr., Walnut Creek, March 30, 10: a.m. to 3 p.m.
- West County Sale: Richmond Public Library, 325 Civic Center Plaza, Richmond, April 6, 10 a.m. to 3 p.m.
- East County Sale: Mangini Garden in the Contra Costa County Fairgrounds, 1201 W 10th St, Antioch.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the March 14, 2019 issue of the San Jose Mercury News.