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.
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.
The best prevention is to be sure your trees are healthy and happy
Woodpeckers are part of the Picidae family that also includes piculets, wrynecks, flickers, and sapsuckers. They are found in most of the world except for Australia, New Zealand, Madagascar, and extreme polar regions. We have 17 species here in California.
They can range in length from just under 3 inches to nearly 20 inches and can be fairly drab in color (olive and brown) to vividly bold (bright red, black, white and gold). They have short, strong legs, and most species have four toes, two of which face backward, making it exceedingly easy to climb and grasp onto tree trunks and limbs.
Although it may seem that a persistent woodpecker is killing your tree, the opposite is generally true. Woodpeckers actually feed on insects that have invaded the bark of an already distressed tree.
Woodpeckers are attracted to wood-boring beetles, termites, carpenter ants, caterpillars, and spiders. However, they will also eat nuts, fruit, bird eggs, lizards and small rodents.
They prefer wood that is already dead for their foraging and nest building. Since most trees have some amount of dead wood, these birds are usually not considered harmful. When they detect insects within decaying wood, they use their strong beaks to make small holes and then extract the prey using their extremely long, barbed tongues.
Sapsuckers, as the name implies, prefer to feast on tree sap and the insects that are attracted to tree sap. These birds are known to voraciously attack trees, causing serious damage and sometimes death to the tree. They are migratory birds and can wreak havoc on entire groves of trees throughout the United States. According to the U.S. Forest Service, sapsuckers cause mortality rates in 67 percent of gray birch, 51 percent of paper birch, 40 percent of red maples, 3 percent of red spruce, and 1 percent of the hemlock that they attack.
They frequently return to the same trees year after year. They increase the size of their holes, looking for more sap and inflicting more and more damage. As the tree declines, bacteria and fungus can take hold, amplifying the damage and increasing the likelihood of tree mortality.
Sapsuckers usually make tiny holes in a horizontal pattern around the tree, while woodpeckers mostly make large, random holes. Most damage is caused during their breeding season that runs from February to June.
All woodpeckers are protected under the Migratory Bird Treaty Act of 1918, and some are listed as endangered species.
So what can you do to protect your trees?
Wrap burlap or hardware cloth around the areas of the tree that have been attacked. There are also repellents such as Tanglefoot Bird Repellent that will help fend off the noisemakers. However, when deterred, they will usually seek out another tree. If they are attacking an already sick tree, one you are not particularly fond of or one that is not in the best location, it may be best to just let them peck in peace!
The best preventative measure is to regularly inspect your trees for signs of infestation. Termites and carpenter ants love to feast on wood, and trees are a good source. So, if you see an invading pest, deal with it right away.
First and foremost, determine what type of pest you have and then use an eco-friendly, organic method of control. When using any pesticide, (organic or conventional) it is important to determine exactly which type of pest you are trying to kill and use only the recommended dose. More is definitely NOT more, and if you aren't careful, you can wipe out an entire ecosystem of beneficial insects and species.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the February 17, 2019 print issue of the San Jose Mercury News.
It's a good idea to know about our local fungi, especially if you have children or pets
Mushrooms are actually the spore-bearing, fruiting bodies of fungi. They pop out of the ground in order to spread their spores for reproduction. They have an underground network of threadlike cells called mycelium that can live for many years, often growing in mulched areas, compost piles or on decaying tree bark and roots.
Mushrooms are a highly sought-after delicacy around the world. But don't start picking them and bringing them into your kitchen without knowing what you're doing. In fact, never consume a mushroom you find unless you are 100 percent certain what it is or have had it properly identified by a qualified professional. I've listed some resources below.
Mushrooms come in all shapes and sizes. Some mushrooms have caps (curved tops) with gills (feathery membranes) or pores (small holes) underneath. The caps are usually supported by stipes (stems/stalks). Others have rings and cups. Some varieties have stems that rise from a cup (also called the volva). In order to properly identify some mushrooms, a “spore print” and molecular identification is often required, said Hung Doan of the UC Davis Department of Plant Pathology.
One of the most common mushrooms here is the turkey tail (Trametes versicolor), which can be found nearly anywhere you find decomposing stumps, logs or old wood. Their clustered, fan-shaped masses have contrasting shades of brown to reddish-brown, and their caps are velvety and slightly fuzzy.
Another common species found in our area is the Armillaria (often called honey fungus), one of the largest living organisms in the world. It is a parasitic fungus that feeds on living and dead plant material. Their yellowish-brown caps can be convex or conical and are generally moist and sticky to the touch.
One specimen of the species, Armillaria solidipes, found in Oregon, is said to be 2,400 years old, and covers more than 3.4 square miles!
Although thought to be rare here in California. I found what appears to be Boletus erythropus in my own backyard. Since the mushroom is not fresh, proper identification can be difficult. Doan said it is likely one of two species — Suillellus amygdalinus (formerly Boletus amygdalinus) or Boletus erythropus.
Its unusual and varied color really caught my eye. The large caps vary from dark to light brown or even coppery bronze. The pores start out orange and then become bright red to rusty brown. The spore tubes are lemon-yellow but turn bluish-green when cut or bruised. They can be found under spruce and beech trees, and occasionally under oaks, as this one was.
Several varieties of mushrooms are toxic, but very few are actually deadly. One of the most deadly found here in the Bay Area is the Amanita phalloides, Death Cap, which has rings and cups as described above. It accounts for nearly 50 percent of all deaths caused by mushrooms. Symptoms of toxicity include severe cramping, vomiting, diarrhea and stomach pain. It can cause liver and kidney damage, and as the name implies, often death.
Its large, spore-less cap can be 2-6 inches wide and can range in color from pale yellow to olive-green. The cap is covered by a thin white veil. Stems and gills are usually white and have a ring and cup (you may have to dig into the soil to see them). It is often mistaken for the edible Paddy Straw mushroom (Volvariella volvacea), which has pinkish-brown gills.
Death Caps are generally found when out hiking and or foraging in our coastal hills where coast live oak and cork trees are found but can be found in urban areas as well.
There are edible varieties of Amanita, but avoid them unless you are a skilled and experienced “shroomer”.
There are many mycologists (those who study fungi) right here in the Bay Area. To learn more, or to join an upcoming foraging adventure, check out these organizations:
- Bay Area Mycological Society (BAMS)
- Mycological Society of San Francisco (MSSF)
- Sonoma County Mycological Association (SOMA)
by UC Master Gardener Rebecca Jepsen
This article first appeared in the January 27, 2019 issue of the San Jose Mercury News.
“Rodale's Basic Organic Gardening: A Beginner's Guide to Starting a Healthy Garden”, by Deborah L. Martin
If you want to start your first garden or want a refresher on the basics of organic gardening, this is a good book to start with. It is written in a friendly, easy-to-read style. It provides information on soil, plant care, pest and weed control, and attracting beneficial insects to the garden.
“California Plants, A guide to Our Iconic Flora”, by Matt Ritter
The gardener interested in California native plants will love this book. The photos are fantastic and there's one for every plant mentioned. Not only does the book list both the common and scientific names, it also includes the history and origin of each plant. There are also maps that show growing regions.
“Private Gardens of the Bay Area”, by Susan Lowry and Nancy Berner; photographed by Marion Brenner
This well-done, coffee table format book showcases more than 35 private gardens in the San Francisco Bay Area. It has stunning photos as well as inspiring landscaping ideas for tiny spaces, hillsides, and even rooftop gardening. Information on soil and microclimates is included as well.
“Hot Color, Dry Garden: Inspiring Designs and Vibrant Plants for the Waterwise Gardener”, by Nan Sterman
Drought and dry weather are becoming the new normal here in California. If you want to have colorful, vibrant, low-water gardens that are teaming with birds, butterflies, and wildlife, this book provides good information and photos to get you going.
“Roots, Shoots, Buckets & Boots: Gardening Together with Children”, by Sharon Lovejoy
This is a great book to get your kids excited about gardening! You'll find instructions for creating a moon garden, pizza garden, pumpkin garden and even a garden in a boot. With a list of the 20 best plants for kids and instructions on making seed tapes, your kids will be digging right in!
“The Flower Gardener's Bible: A Complete Guide to Colorful Blooms All Season Long”, by Lewis Hill and Nancy Hill
Although the authors live on the East Coast, the information and format provided in this book will be useful to both the novice gardener or seasoned guru. It not only offers really good design information, it also has details on soil fertility, plant groupings, watering, cuttings, bouquets, gardening arts, and lighting.
“Golden Gate Gardening ” by Pamela Pierce
The third edition of this famous book, often called the go-to encyclopedia of vegetable gardening, has more than 400 pages of tried-and-true information on growing year-round herbs, fruits, and veggies throughout the San Francisco Bay Area. Concise, clear data is given on what and when to grow from seed and transplant, pests, disease, weeds, watering and even harvesting.
“The New Western Garden Book: The Ultimate Gardening Guide Sunset”, by The Editors of Sunset
Known as the Gardening Bible of the West, and now in its ninth edition, this is THE book almost all nursery experts and gardeners go to. The new addition has added more than 500 new plants and even more photos. It provides details on our local hyper-climates, planting in regard to space requirements, how to plant, plant care, pruning and much, more. …
Thanks to the Master Gardeners who gave their input on great garden books to give: Ingrid Graeve, Janet Hamma, Paula Larkin Hutton, and Heather Dooley.
by UC Master Gardener Rebecca Jepsen
This article first appeared in the December 23, 2018 issue of the San Jose Mercury News.