As avid gardeners,we often choose landscape plants that attract bees and insects, but what if the very plants we purchase contribute to the decline of these garden visitors?
If seeds, plants or flowers have recently been treated with neonicotinoid pesticide, these plants may do more harm than good. First developed in the 1980s, neonicotinoids (neonics) are the first new class of broad-spectrum pesticides in over 50 years.Then eonicotinoid group includes imidacloprid, one of the most popular garden insecticides sold in stores.
Neonics are widely used in horticulture and agriculture for a variety of pests. Like most powerful insecticides, they affect the insect nervous system; however, neonics themselves are comparatively safe for birds and mammals.
A systemic pesticide, neonics are absorbed by the plant and transferred through its vascular system. Consequently, the plant and, to some degree, its nectar and pollen become toxic to insects. The toxin remains active in the plant for weeks and detectable in the soil for years.
Untreated plants can absorb these chemicals from treated plants nearby. As pollinators feed on these plants, they may be exposed to the pesticide. This exposure can have a variety of effects, depending on dose and sensitivity.
Effects on an insect can include disorientation, a weakening of the immune system and death. Even slight exposure to neonicotinoids can affect some bees' ability to navigate or detect odors, impairing their ability to forage for food. While this may seem like it's better than dying, a bee that can't forage effectively may be as good as dead.
In 2013, European Union member states voted to prohibit the use of three neonicotinoids—imidacloprid, clothianidin and thiamethoxam on flowering plants and some crops. A mass die-off of bumblebees in Oregon that same year was attributed to a misapplication of neonicotinoids on linden trees. This outcome led Oregon authorities to adopt permanent restrictions on dinotefuran and imidacloprid, both neonics.
While neonics have little effect on honeybees, they can have profound effects on native solitary bees and bumblebees. These species don't get the headlines that honeybees do, but they are important pollinators.
Many home and garden retailers have already agreed to eliminate neonic-treated plants from their nurseries. When purchasing a plant that is or soon will be in bloom, look for a tag that states that it is neonic-free.
When applying pesticides, read labels carefully. Look for warnings that the pesticide may have adverse effects on pollinators. Follow application instructions, both for your own safety and to avoid killing non-target insects such as pollinators. Consider the consequences of using systemic insecticides containing imidacloprid, clothianidin, thiamethoxam, acetamiprid and dinotefuran, especially on blooming plants attractive to bees.
Avoid combined fertilizer-insecticide products as many of these contain broad-spectrum insecticides. Use safer products such as horticultural oils or soaps. More importantly,practice Integrated Pest Management techniques to control garden pests.Visit http://www.ipm.ucdavis.edu/ for more information on these methods.
Broad-spectrum insecticides are not selective. They can kill beneficial insects like ladybugs as well as other predators and parasites that control pests. That said, neonics don't kill all insects that land on a plant, only insects that eat the plant or its parts. Unfortunately, this can include bees and other beneficial insects if the plant is, or soon will be, in flower and attractive to bees. On plants that are wind pollinated, such as oaks and grasses, this is less of a concern.
Bees and other pollinators pollinate 70 percent of the world's flowering plants, and more than 30 percent of the plants that produce food. As informed gardeners, we have choices. We can purchase safe garden plants and flowers and limit our use of neonics. Creating pollinator-friendly gardens as a food source for beneficial insects is one step to protecting all bees and pollinators.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Fruit Tree Pruning and Care” on Saturday, January 16, from 9:30 a.m. to 2 p.m. The workshop includes a lecture session from 9:30 a.m. to 11:30 a.m. at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. A hands-on session at a local orchard follows, rain or shine, from 12:30 p.m. to 2 p.m. Please dress for outside weather. On-line registration (credit card only); Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
The impetus for the University of California Master Gardener program was to train a “help desk” to assist farm advisors in handling home-garden questions. In Napa County's small Master Gardener office, we have two computers, a phone and a few hundred books on gardening subjects. All of the answers we provide are supported by University of California research.
A few months ago, before the rainy season began, I was working at the Master Gardener help desk. A gentleman came into the office and handed me a sample of something that had been destroying his driveway and tennis court. Another Master Gardener who works at a local nursery had advised him to bring this sample to the help desk for information.
It was not a pretty sight. The nursery staffer had identified it as "dog poop fungus," albeit in less printable language. I took some information from the client and began a search. He said the fungus was growing right up through his driveway. I began perusing the books in our library to see what I could learn. Finally, I went to the computer and typed in the name the nursery staffer had given the specimen. To my surprise, several links came up.
In the meantime, other people had walked into the office and said, "Oh yes, that is growing in my lawn." My computer sources identified it as Pisolithustinctorius. Although it resembles a souvenir from a passing dog, this hard brown item is a true fungus. And as “tinctorius” suggests, it can be used to make a purple dye. Pisolithustinctorius is also called the dye maker's puffball and dog stinkhorn.
After talking with the county weed advisor and the Master Gardener program coordinator, I learned that the fungus grows in connection with tree roots, especially oak and elm. The fungus itself lives underground with the live or decaying tree roots. It is considered a mycorrhizal fungus because the tree roots and the fungus exchange nutrients and water.
Apparently the driveway and tennis court had been constructed in a former treesite. Tree roots were still in the soil. Mycorrhizae can survive in soil even if the tree roots have decayed. You can see the mycorrhizae if you are repotting a pine tree such as a bonsai. Always try to transplant some of the mycorrhizae to the new location. In pine soil, mycorrhizae appear as a white, web-like material.
The above-ground part, the mushroom, is the fruiting
body. It carries the spores that, when dispersed, will produce fungi in new homes. The part below ground is much bigger. According to the Bay Area Mycological Society, ourwarm, dry fall days encourage the fruiting bodies of Pisolithustinctoriusto appear.
Many fungus and their fruiting bodies need damp conditions to grow and reproduce. They thrive on decaying materials such as leaf litter, downed limbs and compost piles. In these settings,mushrooms will mature and open to release their spores. The fruiting bodies of Pisolithustinctorius are poisonous and certainly not appetizing.A fungicide will eliminate the fruiting bodies but not the underground fungi; when conditions are right, they will fruit again.
In the past, I had thought of mushrooms only as a delicious ingredient. But my reading revealed that the fungus family is a large one, neither plant nor animal. Scientists refer to the “fungi kingdom,” a reflection of how diverse it is. Some fungi are beneficial and used for medicines such as penicillin, but others are toxic, even deadly. You can even buy mycorrhizae to improve your soil, but those are not Pisolithustinctorius. You can view a photo gallery of fungi at www.kingdomoffungi.com.
Now that the Master Gardener help desk has identified this homeowner's problem, we are waiting to hear from you with another challenge. Please bring any plant or insect samples in a sealed plastic bag.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance. On-line registration (credit card only); Mail-in registration (check only).
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Fruit Tree Pruning and Care” on Saturday, January 16, from 9:30 a.m. to 2 p.m. The workshop includes a lecture session from 9:30 a.m. to 11:30 a.m. at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. A hands-on session follows from 12:30 p.m. to 2 p.m. at Silverado Middle School, 1108 Coombsville Road, Napa. On-line registration (credit card only); Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
Who in California needs holly? We Californians are fortunate to have a beautiful native shrub that resembles holly but outshines it. Like holly, toyon (Heteromelesarbutifolia) is evergreen and has bright red berries in winter, but it is easygoing, hearty and well adapted to our lower elevations
Toyon occurs extensively in the chaparral and woodlands surrounding the Central Valley and in other foothill regions of the state below 4,000 feet. In fact, its resemblance to European holly and its abundance in Southern California explain the origins of the name Hollywood.
Toyon got its name from the Ohlone tribe. It is also called Christmas berry or California holly. A member of the rose family, toyon typically grows 8 to 15 feet in height and width. However, some specimens grow larger and work in the landscape as small trees.
The plant has dark green, leathery, oblong leaves that are two to four inches long. In spring, the shrub is covered in flat-topped clusters of fragrant white flowers that attract bees and butterflies. As the season progresses, the flowers give way to dense clusters of small, orange-red berries that last late into the year.
These berries attract many local birds: American robins, quail, towhees, cedar waxwings, mockingbirds and various finches and sparrows. So in addition to its beauty, toyon is an excellent habitat plant. The berries also make the plant useful for home décor at Christmas, if you can get to the berries before the birds do.
Like many of its cousins in the rose family, toyon is susceptible to fireblight. The cultivar ‘Davis Gold,' developed at the University of California at Davis, has striking yellow berries and improved disease resistance. Toyon tends to be ignored by deer, although desperate deer may eat the new leaves of smaller plants.
This hearty California native tolerates serpentine, adobe and sandy soils. Unlike some other members of the rose family, toyon requires little pruning to make a great screen or help with erosion control.
For best results, don't try to contain it in a pot. Plant it in full soon and give it room to grow. Although it can take some light shade, it will be fuller and more compact in direct sun. Water deeply and infrequently the first few years to encourage deep tap roots, then sit back and enjoy all its berry beauty-ness. If you like to bird watch, be sure to plant it where you can watch the birds gorge on the winter berries.
So if Hollywood was named after the Christmas berry, could it be that the “vine” of the famous intersection Hollywood & Vine was named after another California native,Vitiscalifornica(California grape)?Heteromeles&Vitis.Toyon& Grape. Neither pair rolls off the tongue quite as nicely as Hollywood & Vine.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance. On-line registration (credit card only); Mail-in registration (check only).
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Fruit Tree Pruning and Care” on Saturday, January 16, from 9:30 a.m. to 2 p.m. The workshop includes a lecture session from 9:30 a.m. to 11:30 a.m. at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. With hands-on session at a local orchard, rain or shine,from 12:30 p.m. to 2 p.m. Please dress for outside weather conditions.On-line registration (credit card only); Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
On a recent December morning, I wandered out to the vegetable patch to see how the broccoli plants were faring. I started these plants from seed in early September and transplanted them into the ground on September 26. Initially I covered them with wire cages to keep birds from shredding them, but lately the plants have outgrown the cages and I wanted to see if they were being eaten.
Birds are nibbling, but the plants are starting to form heads and I am hoping that we'll soon be eating home-grown broccoli. I noted in my garden journal that if I want broccoli for Thanksgiving, I need to set plants out in August.
I also checked the lettuce to see if there is anything left to harvest. This bed was seeded in August, and we have been eating salad greens for a couple of months. The plants are fairly bedraggled now, but a surprise was waiting for me in the garden path. Recent rains have provided enough moisture to sprout some arugula from a spring crop that went to seed. If the arugula weren't edible, I'd consider it a weed. Already the plants have one- to two-inch leaves, just right for salads and pizza topping.
If arugula seeds can sprout in December, you know other edibles will grow. Try planting fava bean, parsley, radish and spinach seeds. If you can find nursery seedlings, you could also set out kale, broccoli, lettuce, chard and other greens. Everything grows slowly now, but you can expect some delicious eating in February and March.
It's not too late to set out garlic. If you can't find garlic in nurseries, try organic garlic from the grocery store. Planted now, it will not mature until late May or June, but you can harvest green garlic at any stage.
It's also not too late to set out a few annual flowers for color. Check a local nursery to see what is available. I have a fondness for pansies and violas and usually set out a few plants in the winter vegetable patch. They add color to the beds and to my salads, too.
The peach and apple trees in my yard have lost nearly all their leaves. This leaf drop signals the start of pruning season for deciduous trees, roses and grapes. Remove diseased or damaged branches first. Then assess the tree from all directions before pruning for shape and fruit production.
Some trees, including many apple varieties, produce fruit on spurs (short stubby twigs) over many years, while other fruit trees produce fruit on new shoots every spring. Since this influences the way these trees should be pruned, consult a book, a tree expert, or Napa County Master Gardeners (office hours below) if you are not sure. For ornamental trees, prune mostly for shape.
If I waited for the roses in my garden to lose their leaves, I might never prune them. Go ahead and startcutting them back now. You will be rewarded with healthier plants and more blossoms next spring and summer.
One of my neighbors has a lovely Fuyu persimmon tree in the front yard just dripping with ripe fruit. I have found myself wishing I had my own share of those persimmons. Luckily, bare-root planting season has now begun. Plants sold in the bare-root state include deciduous fruit and shade trees; roses; vines such as clematis, wisteria and grapes; flowering shrubs such as lilacs and berries, including cane berries, blueberries and strawberries; and the perennial vegetables artichokes and rhubarb. The plants are field grown by the propagator, dug up while dormant and sold without soil clinging to their roots. Consequently, they are easier to handle than plants in pots and usually quite a bit less expensive. If you have found yourself coveting your neighbor's unpicked fruit tree, it might be time to plant your own.
Local nurseries will have their largest supply of bare-root plants in January, but now is a great time to order by mail. Bare-root plants need to go into the ground as soon as possible to protect the roots from dying out. If possible, prepare planting holes during a spell of dry weather so they are ready when you bring the plants home. If your soil is too wet for immediate planting, “heel in” the roots temporarily in damp compost or sand in a shady location. Cover the planting area to let it dry out a bit.
Whatever the December weather, you can spend some time in the garden. Maybe you will find some pleasant surprises there.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance. On-line registration (credit card only); Mail-in registration (check only).
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Fruit Tree Pruning and Care” on Saturday, January 16, from 9:30 a.m. to 2 p.m. The workshop includes a lecture session from 9:30 a.m. to 11:30 a.m. at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. A hands-on session follows from 12:30 p.m. to 2 p.m. at Silverado Middle School, 1108 Coombsville Road, Napa. On-line registration (credit card only) coming soon; Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.
Chilly nights challenge our citrus trees, succulents and other frost-tenderlandscape plants. On top of the seissues, holiday commitments take up a lot of the time that one might otherwise spend in the garden.
So what should a gardener be doing this month?Some tasks are priorities, so let's tackle those first. If you have citrus trees or other tender plants, you must mitigate their exposure to frost or they will suffer. Already I have recorded night-time temperatures below 30°F at my home.
I have five citrus trees in four locations, so I use a combination of strategies. For the two trees close enough to the house to reach with an outdoor extension cord, I have strung Christmas lights (not LED type) in the branches. I plug in the lights on cold nights. Another tree, a dwarf citrus, is short enough that an old patio umbrella clears its branches. I toss an old comforter over the umbrella ribs when frost threatens. For the other two citrus, I set up ladders to support tarps and old blankets. Once the temperature begins to rise in the morning, I remove all the coverings and unplug the lights. Unless we get an arctic blast, all of these trees should survive the winter.
Water is also a priority. Until rains thoroughly wet the soil, I pay attention to my rain gauge. If we have less than an inch of rain in a two-week period, I figure that any actively growing plants will need irrigation. In my garden, that's mostly vegetables. My fall-planted greens are producing lots of leaves for stir-fry and salad, and November garlic is beginning to emerge.
Citrus trees will also need some water, especially if the weather is cold. During the summer I used gray water from my laundry to water my roses; now that those plants are going dormant, I'm using the gray water for citrus trees. I have switched to a plant-friendly laundry detergent and have not noticed any negative effect on the plants irrigated with gray water. But note that I only use gray water on trees and shrubs; the vegetables get potable water.
Already we have had enough rain in Napa Valley to start greening our hillsides. But the same rains have prompted weeds to emerge in my garden beds. While these weeds are small, they are easy to pull or hoe. Weeds take just as much water as edibles, so removing them now will conserve water for the plants I want.
As you weed, note areas of bare soil. If possible, cover bare spots with mulch or compost, or plant a cover crop if you can keep it moist. Winter is hard on soil. Rain compacts it; wind and sun dry it out. Soil is the foundation for all of your plants so protect it. Earthworms, fungi and other soil microorganisms will reward you with healthier soil next spring when it's time to plant.
Last but not least, finish your fall cleanup. Remove spent vegetable plants. Put diseased plant material in your yard-waste bin rather than in your compost pile. Most backyard compost piles do not get hot enough to destroy pathogens. In contrast, the waste-management companies compost at high temperatures that do control bacterial and fungal diseases. Rake up leaves and other litter to eliminate hiding places for snails, slugs and harmful insects.
In next week's column, we'll look at December gardening activities that are less like maintenance and more like fun. Although I have to admit, on sunny winter days I am perfectly happy to be outside even if all I do is pull weeds. It makes a nice break from working on the computer or in the house.
Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Pruning and Maintenance” on Saturday, January 9, from 10 a.m. to noon, at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. This workshop will feature demonstrations of proper pruning techniques. Master Gardeners will discuss types of roses, common rose diseases and routine maintenance. On-line registration (credit card only);Mail-in registration (check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.