Do you know a U. C. Master Gardener of Napa County? You may and not even realize it. We are short, tall, thin and not so thin. We are older, younger, retired and still working. We live in Calistoga, Pope Valley and American Canyon and all points in between. The one thing we have in common is a passion for gardening.

The Master Gardener program began in 1972 in Washington State. Now almost every state has a Master Gardener program. Its purpose is to assist the county farm advisor in answering local home gardeners' questions. The Napa County Master Gardener program graduated its first class in 1995.

Prospective Master Gardeners are interviewed to make sure that they are willing and able to complete the volunteer commitment. Those accepted attend a 10-week training program of weekly classes.

Master Gardeners are not trained to know everything about gardening, but we know where to find information and resources. We guide the public in becoming better gardeners. To that end, we rely on a mountain of research-based information from the University of California. We dispense only research-based information, not the folk wisdom learned at a grandparent's knees.

There are many ways that Master Gardeners can earn their minimum number of volunteer and continuing-education hours. One of the main ways we educate the public is via office hours. This help desk is one of my favorite places to work. We have a small office in the U.C. Cooperative Extension office in Napa with a computer and many reference books. Master Gardeners hold office hours here and answer garden questions from Napa County home gardeners.  

I once fielded a question about how to grow wasabi (horseradish). I searched everywhere for information and finally found on a university website. Master Gardeners sometimes have to be detectives.

We also conduct public workshops throughout the year on seasonal topics. We staff garden- information tables at farmers' markets, garden centers, health fairs and county and city events such as Earth Day. We partner with local waste-management agencies to host backyard-composting classes on both hot composting and vermicomposting (composting with worms). We maintain demonstration gardens to illustrate useful techniques and plantings. We recently completed a drought-tolerant planting in Calistoga and a pollinator- attracting garden at the St. Helena Library.

Our School Garden Task Force helps parents and teachers manage local school gardens. Master Gardeners contribute weekly newspaper articles and operate a speakers' bureau. If you belong to a group that needs a guest speaker on a garden topic, check our website (address below) for the speakers' bureau request form.

Master Gardeners of Napa County will also host two major events this spring. The annual Tomato Sale and Education Day on Saturday, April 8, and the “Discover Garden Magic” garden tour on Sunday, May 21. At the tomato sale, you can purchase a wide variety of tomato seedlings and learn how to take care of them. The garden tour showcases six splendid gardens owned and maintained by Master Gardeners. These gardens will inspire you and provide ideas for your own home garden. Proceeds from these events support our educational efforts in Napa County.

Visit our website (http://ucanr.edu/ucmgnapa) to find useful information on gardening, submit a garden question to our help desk, request a speaker or learn about upcoming events. A new group of Master Gardener trainees will graduate at the end of March, joining experienced volunteers working in the community on our many educational projects.

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.edu/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.

I haven't always appreciated leeks. I grew up in a home where we never ate them, so I didn't encounter leeks until I was an adult. For many years I considered them kind of exotic and only cooked with them occasionally. Gradually I came to appreciate their unique flavor and sweetness and began to explore growing them in my garden.

Leeks are part of the onion family, which includes garlic and shallots as well as scallions (green onions) and familiar bulb onions. In flavor they resemble mild onions. In cooking, I've found that if a recipe calls for leeks but all I have are onions, I can still make the dish, and vice versa

When the Master Gardener field trial group decided to grow leeks last year, I enthusiastically joined in. I figured that growing them myself would provide a steady supply of fresh leeks all year.

The plan was to grow two kinds: an open-pollinated variety called ‘Lancelot' and a hybrid named ‘Megaton.' We hoped to learn whether one had any advantages over the other in flavor, size or vigor. I also hoped to learn more about growing them.

Leeks are considered a cool-season vegetable, and most sources recommend planting seeds or transplants in fall. Pam Peirce's book, Golden Gate Gardening, suggests early spring planting for a crop through summer and fall. This was the approach we decided to take.

Two of us agreed to start plants for the whole group. Seeds were started in nursery containers in January. Because leeks grow slowly and do not require much room, they can be sown relatively thickly. The seed packets said to sow seeds ½ inch deep and ½ inch apart. A four-inch pot handled 16 to 20 seeds easily with that spacing.

Seeds sprouted readily, in less than two weeks. After about eight weeks, around the middle of March, the seedlings were beginning to crowd the pot. They were sending roots out the bottom, indicating that it was time to transplant them into the ground.

Leeks prefer enriched soil so most of us added compost and fertilizer to our planting beds before setting the plants out. Spacing them at least six inches apart would allow the plants to develop to their mature size of one to two inches thick. They need regular water, and most gardeners used a drip line and watered a couple of times a week. Leeks have relatively shallow roots, so frequent watering is better than deep soaking.

Leeks take a long time to size up. While you can eat them at any stage, we were aiming for large leeks similar to the ones in the grocery store. With that standard, we harvested the first leeks around 90 days after transplanting, right on time according to the seed packet. That equates to harvesting in late June and July. Some of the gardeners continued to have a good-quality harvest into fall, with the leeks getting a bit larger with time.

Ten Master Gardeners reported results. As this is a small sample and we planted relatively few seedlings (10 to 20 of each variety), our findings are not statistically valid. Still, they are worth sharing. Fewer than half of the leeks we transplanted made it to maturity, mostly due to gophers or squirrels finding them irresistible. We found ‘Megaton' somewhat better than ‘Lancelot' in terms of size, but we disagreed on which variety was tastier.

Of the ten Master Gardeners who participated in the trial, more than half said they will grow leeks again. For me, having fresh leeks in the summer was convenient. Prior to this experiment, I had confined my leek planting to fall.

While I have enjoyed some success growing leeks over the winter, they never lasted past spring without bolting. Now that I know that leeks planted in early spring will do well through the summer, I intend to start leek seeds once or twice in late winter so I can enjoy these versatile onion relatives more often.

Workshop: U. C. Master Gardeners of Napa County will host a work on “Ten Things to Know about Fruit Trees” on Sunday, February 12, from 11 a.m. to 1 p.m., at the Yountville Community Center, 6516 Washington Street, Yountville. Fruit trees want to produce fruit. Learn how home gardeners can nurture their fruit trees to be as productive and healthy as possible. Cost is $12 per person; free to Yountville residents. Register with Yountville Parks & Recreation or call 707-944-8712.

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.edu/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.

By Tony Nunes, U.C. Master Gardener of Napa County

Knowing basic botany and grapevine structure and selecting a variety and rootstock suited to the location can help vineyard owners succeed. Master Gardeners call it putting the right plant in the right place.

We are fortunate to live in a region with soil types and microclimates that produce world-class wines. Just like commercial vineyard managers, home vineyard owners need to make decisions based on their unique site, goals and conditions and make adjustments driven by Mother Nature throughout each growing season.

It starts with a vineyard management plan for the season. Napa Valley has kicked off the year with rainfall amounts and low temperatures not seen in many years. Determining pruning dates is the first step. In some places, pruning has already started as vineyard managers allocate their resources throughout the valley.

Home vineyard owners may have the flexibility to delay pruning, which in turn delays bud break and minimizes the potential for damage from a late frost. Some people make two passes, first to remove last year's old canes, then to make the final command decision: the pruning of buds created during the 2016 growing season that will produce the crop for this year's harvest.

As our growing season progresses, days get longer, soil temperatures rise and grapevine sap begins to flow. This awakening from winter dormancy is one of many milestones of the growing season.

One element of integrated pest management is a plan for controlling powdery mildew (Uncinula necator) and botrytis (Botrytis cinerea) from bud break to veraison, the color change in grapes that signals the onset of ripening. The spores that cause powdery mildew or botrytis are ubiquitous in Napa Valley vineyards.

Powdery mildew infections from the previous year appear as a blue fungus on individual berries or clusters. Botrytis affects the internal tissues of the berry or the entire cluster. Berries split and fungal spores can grow out of split skins. The spores from infected clusters are distributed easily by wind. Spores can survive the winter on the grapevine bark and cause infections the following year.

Early in the growing season, vine shoots grow rapidly. Like a jack-in-the-box, buds produce shoots and a self-pollinating flower blooms to produce the year's crop. Bloom and fruit set are critical periods driving yield and fruit quality. Temperature swings and rain are not welcome during this time.

Grapevines do not required special fertilizers but should be kept in balance with nutrients available in the soil. Too much nitrogen in the soil can cause vines to produce excess canopy, creating issues with pest management and crop quality.

When applying fertilizer, first ask yourself why. Testing can help you determine what the vine needs. The first test of the growing season, petiole testing, should be performed after fruit set. Petioles connect leaf blades to the vine shoot. Samples of 25 to 50 petioles are selected for each block and tested to determine what nutrients might be deficient or present in excess. Fertilizers are then applied according to the specific needs of that block.

Grape clusters need leaves and sunshine to ripen the crop. Additionally, new buds require sunshine to produce energy for next year's crop. Managing the amount of leaves and their health is referred to as canopy management.

Removing leaves at the base of the canes surrounding grape bunches allows for better sunlight penetration and airflow. To guide decisions about leaf removal, growers observe weather conditions and how the vineyards are oriented to the sun. Leaf removal on the west side facing the afternoon sun is limited during July and August to minimize sunburn and bunch rot. Home grape growers may also need to observe their microclimates or placement of buildings when determining how to manage the canopy.

Irrigation decisions also affect canopy health. Vineyard managers monitor soil moisture levels and visual clues from leaf blades and tendrils during the early season's rapid shoot growth, flowering and fruit set. When irrigation is needed, it is best to irrigate deeply according to the site's soil-moisture holding capacity.

Roots don't grow in dry soil. The goal is to encourage roots to grow as deeply as possible given the site's soil conditions, with just enough water stress to produce high-quality fruit.

Home vineyard owners are generally optimists or at least try to be. Each year, they look forward to a successful harvest, drawing on the knowledge gained from previous growing seasons.

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.edu/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.

Pat Hitchcock, U.C. Master Gardener of Napa County

Weeds aren't the only troublesome invaders in many Napa Valley gardens. Several other plants, not usually thought of as weeds, can be equally problematic. These thugs are the larger plants, shrubs and trees that, if left undisturbed, can spread into native habitat and crowd out native species.

Cotoneaster is a shrub in the Rosaceae family that grows enthusiastically in my neighborhood. The New Sunset Western Garden Book describes its growth habit as fountain-like with “graceful, arching branches.” Its summer sprays of small white flowers become red-orange berries in fall. Robins, cedar waxwings and other birds love them.

While cotoneaster is native to Eurasia, most of the cultivated varieties originated in China. They were introduced in California before 1900 but have only been reported as invasive in the last 20 years or so. With help from birds, they self-seed abundantly and can supplant native toyon (Heteromeles arbutifolia) in natural areas.

Another problem plant is the Himalayan blackberry or Armenian blackberry (Rubus armeniacus). Native to Armenia and Northern Iran, this plant was introduced to North America in 1885 as a fruit crop. It soon escaped into the wild and is considered invasive throughout temperate climates. While the berries are delicious, the plant is thorny and rambunctious. Canes can grow 30 feet long.

The plant propagates not only by seeds but also by “tip rooting” when the tip of the cane touches the ground and forms roots. If you ignore this plant for long, it creates a dense tangle of old brown growth and wicked, thorny green canes. It likes to grow among other shrubby plants, including the climbing roses and butterfly bushes (Buddleja) that screen my front bedroom windows from the street. Removing the blackberry vines that wander into that bed requires protective clothing as well as sharp pruners and a sturdy digging tool for prying out roots.

While the cotoneasters and blackberries probably invaded my property, another troublemaker—privet—was planted intentionally as a hedge. Three species of privet (Ligustrum spp.) are on the

California Invasive Plant Council's watch list, which means they have not yet been rated invasive in the state but are raising concerns. Those three are glossy privet, Japanese privet and California privet. Glossy privet (Ligustrum lucidum) is likely the one growing (and spreading) in my yard.

If kept trimmed, glossy privet makes a dense hedge. However, if left unclipped, it will reach tree height, bloom heavily in spring and produce a large crop of small black berries. The falling fruit can stain pavement and make a mess on parked cars. Birds attracted to the berries contribute to the mess and help spread the seeds, so new plants volunteer everywhere. After the fruit is gone, the fruiting clusters are unattractive. Sunset advises readers to consider the disadvantages of privet before planting it. I wish whoever planted it on my property had done so.

My property also has an abundant supply of ivy (Hedera helix, H.canariensis). Ivies are native to Eurasia and northern Africa but are now widespread. The California Invasive Plant Council lists ivy as being high in impact, invasiveness and distribution. I try not to let it climb into trees, and I pull it off the north side of the house, where it seems to like the micro climate. It infiltrated the overgrown hedges along the street and provided some screening where it grew densely on an old wire fence. I didn't think anything could kill ivy, although, after five years of drought, a small section in front of my house spontaneously died.

Once I was answering calls at the Master Gardener Help Desk when a client called to ask if we could help him figure out why his ivy had died. After doing some research, I was still stumped; this is a plant that does not succumb to pests or disease. I consulted a U.C. farm advisor specializing in weed science, and now we would both like to know why that ivy died. Finding an efficient way to control ivy in our forests and riparian areas would be a wonderful discovery. Meanwhile, in my yard, I whack it back from time to time in an effort to keep it from taking over.

All of these plants were brought to California intentionally because they had characteristics that seemed useful or attractive. Some of them are still sold in nurseries. But in our state's hospitable climate, the plants have escaped cultivation to become nuisances in wild areas as well as in some gardens.

For more information about invasive plants, check out the California Invasive Plant Council's website, CAL-IPC. The lesson here is to consider the unintended consequences of the things we do. After researching weeds for the past few weeks, I am vowing to be careful about the new plants I introduce into my garden.

Workshop: U. C. Master Gardeners of Napa County will conduct a workshop on “Rose Pruning and More” on Sunday, January 22, from 1 p.m. to 3 p.m., at the Yountville Community Center, 6516 Washington Street, Yountville. Learn 10 important facts about roses, rose pruning and rose care and maintenance. Registration is $12 per person, free to Yountville residents. Register with Yountville Parks & Recreation or call 707-944-8712.

Workshop: The Integrated Grape Team from the U. C. Master Gardeners of Napa County will host a workshop on “Home Vineyard 1” on Sunday, February 5, from 12:30 p.m. to 4:30 p.m., at White Rock Vineyards, 1115 Loma Vista Drive, Napa. Learn what to do, what to look for and what to plan for in the vineyard between February and August. This is an outdoor lecture so dress accordingly. Registration is $5 per person.Online registration (credit card only) Mail-in registration (check only or drop off cash payment)

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.edu/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.