By Susanne von Rosenberg, UC Master Gardener of Napa County
As a gardener, you are doubtlessly painfully aware of how little rainfall we had during our last rainy season. According to the United States Drought Monitor, Napa (along with more than 50% of the entire state) is currently in an exceptional (category D3) drought.
Some counties have already imposed water conservation requirements. We can count on Napa County and its cities having to do so as well.
During an exceptional drought, fire season lasts year-round. Water is inadequate for agriculture, wildlife and urban needs, and reservoirs are extremely low. In addition, our soils are already pretty dry and cannot serve as a reservoir for our plants in the late spring and early summer, as they normally do.
So, knowing that water conservation requirements are coming, your plants need irrigation sooner than they would during a normal rain year. As a good steward of the planet, what can you do to better prepare your garden to use less water?
In addition to continuing to make your garden more water-wise in general, you can take specific steps now to reduce the water needs of your garden. Make yourself a checklist and make May your drought-preparedness month.
Two of the easiest things you can do to use less water are to mulch your garden and to move to drip irrigation wherever possible. Before you mulch any part of your garden that isn't currently mulched, make sure that you water well so that the soil is moist below the mulch. Then install drip irrigation, and mulch over the drip irrigation, if possible. If you install irrigation over the mulch, water will have to moisten the mulch first before it can penetrate to the soil.
If you are currently hand watering or using sprinklers, installing drip irrigation will help ensure that the only the plants that need water are getting it. You can easily install a drip system yourself. Drip irrigation waters slowly, which means the water has time to penetrate the soil. You save water by preventing run-off and evaporation, and you get fewer weeds.
Then make sure you only water when necessary. For annuals and shallow-rooted perennials, it's time to water when the soil is dry two inches down. For trees, you can wait until the soil is dry at least six inches down. Get to know your plants and understand what signs of water stress look like.
Given that we are in an exceptional drought, the more you do to conserve water in your garden, the better. Another important tool in water conservation during a drought is to prune your trees hard. Preserve leaf canopy that provides shade to your house and other plants but reduce the size of ornamental and fruit trees that don't provide a direct shade benefit.
The smaller the tree, the less water it will need. You can safely prune back fruit trees by one-third. If you expose any limbs that have previously been shaded by leaves, paint them with white interior latex paint (diluted with an equal amount of water) to protect them against sunburn. You should also thin fruit on fruit trees to reduce water demand and get better fruit.
You can reduce the water needs of delicate plants by creating afternoon shade for them. Install shade cloth or other materials to block the afternoon sun.
Think about what parts of your garden are most important to you. You may have to decide not to water certain plants. What are your priorities? You'll probably want to focus on saving perennial plants, especially trees. Although I have a vegetable garden, I would definitely let that go in favor of watering my fruit trees.
You can also rethink your garden. Are there parts that are particularly thirsty? Maybe this is the year to remove those plants, and plan to replant in the fall with more drought-adapted plants.
If you have any unneeded lawn, consider replacing it. Stop watering it and work on a replacement plan to implement in the fall.
Delay any new plantings until we get adequate rain unless the new plantings will require considerably less water than what they are replacing.
Finally, know that your perennials can survive on less-than-optimal amounts of water. When plants lack water, they conserve by closing the stomata (openings) in their leaves that allow water to evaporate. Photosynthesis stops because the plant is no longer getting any carbon dioxide from the air. The result is that the plant won't grow as much as it would with optimal water. Let it catch up in a wetter year.
I encourage you to start now to conserve water, doing your share to help make sure we have enough water to go around.
Food Growing Forum: On Sunday, May 9, UC Master Gardeners of Napa County will host a discussion on “Beans and Summer Pruning of Fruit Trees” from 3 p.m. to 4 p.m. Register to get the Zoom link.
Library Talk: On Thursday, May 6, from 7 pm to 8 pm, UC Master Gardeners of Napa County will hold a virtual talk on “Right Tree, Right Place: Making Smart Tree Choices for Your Landscape.” Register to get the Zoom link: http://ucanr.edu/2021MayRtTreeRtPlace
Tree Walk: On Tuesday, May 11, from 10 am to noon, UC Master Gardeners of Napa County will host a docent-guided tree walk in Fuller Park in Napa. Group size is limited to seven. To register: https://bit.ly/2Qg3tib
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
By Susanne von Rosenberg, UC Master Gardener of Napa County
Many of us set goals at the start of a new year, and most of us give up on them fairly quickly. How about focusing on your garden this year instead? That will probably be a lot more fun than any resolution you were going to make.
Your garden intention can be an enjoyable way to improve your health and well-being and help the planet, too. Win-win-win! Set an intention rather than a goal. An intention creates a path you follow and avoids the stress of having to meet a specific expectation. After all, gardening should be enjoyable.
So what will your win-win-win garden intention be this year? Here are some ideas:
Consider making your garden more environmentally friendly:
Reduce your water use. Install drip irrigation (it's really not that hard) or focus on rainwater harvesting. Alternatively, replace some particular thirsty plants with drought-tolerant choices.
Improve your soil. Keep mulching and use organic fertilizers. Your plants and the planet will thank you.
Plant more native plants. They're beautiful and,once established, need little care.
Choose plants that support native pollinators. We need to support diversity in the pollinator population.
How about planting some plants that will help reduce your energy consumption by shading your home or its south- and west-facing windows?
Learn more about climate-friendly gardening. For example, did you know that you can help trap carbon in the soil through the right kinds of gardening practices? And these practices improve your soil, too.
Create habitat for wildlife. In addition to planting native plants and other plants to provide food for wildlife, provide water and shelter. Leave your garden a little messy; it's better for wildlife.
Replace your lawn with drought-tolerant plantings. All of the cities in Napa County have cash-for-grass programs that pay you to remove your lawn and replace it with a drought-tolerant garden.
Learn to make compost. It's the best way to recycle your yard waste and some food scraps. And if you can't make enough compos to mulch your garden, buy it from the municipal waste company.It's inexpensive and certified as a soil amendment for organic agriculture.
Learn more about your garden:
Spend more time observing it. How does the light and shade change throughout the year? Where does the rainwater flow? How does the wind affect your garden? Which critters call it home?
Track the daily high and low temperature and the rainfall in your location. You can find inexpensive gauges in most garden centers and nurseries and online. Keep a notebook or other journal to record what you observe.
Experiment with something new: new plants, new tools or new ways of taking care of your garden. Did you know that no-till gardens are the wave of the future?
Make your garden work better for you:
What are the big challenges in your garden, and what one action could you take to make the biggest dent in dealing with that challenge?
What can you do to make your garden more enjoyable? Do you need more seating? Or perhaps more shade or sun? Do you want to create a peaceful nook for meditation?
Simply spend a bit more time gardening. Fifteen minutes a day can have a big effect and will make for a relaxing break, no matter what time of day you go out.
Consider contributing fresh produce to the local Food Bank (check first to find out what is needed). This is a wonderful activity to share with kids.
Do you have grandkids or nieces and nephews? How about introducing them to the joys of gardening?
Knowledge makes you a better and more confident gardener. Check out the Master Gardener website (http://napamg.ucanr.edu/) for useful information as well as upcoming workshops and events.
Or you could simply decide to spend more time in the garden. Fresh air and being in nature are wonderful for your heart and soul. Being more at peace is a wonderful intention for the new year.
Workshop: The U. C. Master Gardeners of Napa County will present a workshop on “Growing Spring and Summer Vegetables” on Saturday, March 9, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Do you want nutritious, easy-to grow and utterly fresh food from your garden this spring and summer? Learn what the garden needs to successfully produce spring and summer vegetables from seeds and plant starts. In addition to growing basics and hands-on activities, this program includes watering, fertilizing and harvesting tips, with a dash of Integrated Pest Management for pest and disease control. The delight of growing your own groceries is matched only by savoring them at harvest. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).
Workshop: The U. C. Master Gardeners of Napa County will present a workshop on “Summer Vegetables” on Sunday, March 10, from 1 p.m. to 3 p.m., at Yountville Community Center, 6516 Washington Street, Yountville. Get tips for growing your own summer vegetables. Learn some basics, get keys to success, and do hands-on activities to learn about new varieties and review old favorites. Enjoy healthy vegetables taken straight from your garden to your table. The delight of growing your own vegetables is matched by savoring them at harvest. Online registration or telephone the Parks & Recreation Department at 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:/napamg.ucanr.edu) 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.
A few years ago, back during the drought, I was ready to give up on hydrangeas. They were the coal-mine canaries of my yard, the first to droop if they were dry, and after the first few years not blooming much.
They also received different amounts of filtered sun so they were of different sizes. My enthusiastic but haphazard pruning hadn't helped, either.
Looking for inspiration, I walked around downtown Napa. I noticed that few of my neighbors seemed to care about symmetry, and their lovely hydrangeas were of differing shapes and sizes.
The varieties were different, too. Lacecap and mophead types (Hydrangea macrophylla) often appeared in the same yard, and by the time I reached the commercial area of Napa, I observed another specimen much in vogue—the oakleaf hydrangea (Hydrangea quercifolia).
I decided to replace one hydrangea at the end of the row with the oakleaf variety. It was so obviously different that symmetry would be a non-issue. And it was tall, with large, deeply lobed leaves and showy cones of creamy flowers.
I also learned that one reason the oakleaf hydrangea is so popular around local hotels and restaurants is that it requires less water than other varieties. In the winter, its peeling bark and bronze leaves provide some interest.
Oakleaf hydrangea flowers on old growth, so it should be pruned after its first bloom. This winter I broke that rule and did a light pruning to shape it, but I made sure to keep a lot of buds on the stalks. Helped by this year's generous rainfall, my oakleaf hydrangea should be more luxuriant than ever this summer.
Hydrangeas are beautiful shrubs that reward the home gardener with a spectacular flower display if they are watered and fertilized adequately and pruned at the right time. Keep the soil moist, not wet, to a depth of one inch. (Oakleafs require less water.) A layer of mulch will keep the soil moist longer. Hydrangeas like sun; filtered sun is best for keeping their color.
Fertilizing is also important. When you plant a hydrangea, dig a hole three times the size of the container. Then fill the planting hole with a 50/50 blend of soil and an acidic amendment, such as a commercial soil mix for camellias and azaleas. Dig in some compost to improve texture. Plant the shrub so it is level with the ground and add a one- to two-inch layer of mulch.
Fertilize in early spring or summer. The bloom color of some varieties reflects how acidic or alkaline the soil is. Alkaline or neutral soils produce pink flowers; acid soils produce blue flowers.
To produce blue flowers, you may need to acidify the soil. Use a water-soluble acidic fertilizer with few or no phosphates, since phosphates are alkaline. In the fall, apply one teaspoon of aluminum sulfate per foot of plant height. Mix with water and drench the soil. Don't expect a change overnight.
For pink flowers, you need soil with a pH of 7.0 to 7.5. If necessary, adjust with a balanced fertilizer, but add superphosphates in the fall or winter. It is easier to turn flowers pink than blue. Don't fertilize after August, as hydrangeas are preparing for dormancy.
As for pruning, first determine if your hydrangea blooms on new or old wood. Old- wood bloomers (hydrangeas that produce buds on the previous season's stems), such as broadleaf hydrangeas and oakleaf hydrangeas, should be pruned after they bloom. Remove weak, dead or crossing stems. (Scrape your knife along a stem; if you don't see green, it's dead.) Make sure to leave green stems, as they will be setting buds. With these varieties, prune only for shape and remove no more than 30 percent.
New-wood bloomers such as ‘PeeGee' (Hydrangea paniculata) and ‘Annabelle' (Hydrangea arborescens) produce buds on new stems. They can be pruned any time except when they are preparing to bloom. You can prune these varieties more aggressively but avoid taking them down to the ground in fall. They can have large flower heads that need support from some old growth.
Hydrangea leaves and buds are poisonous if eaten. According to the California Master Gardener Handbook, animal poisonings were reported in older literature, but no recent cases have been reported. Wear gloves when pruning to prevent contact dermatitis.
With just a little care, hydrangeas will reward you with color all summer.
Workshop: U. C. Master Gardeners of Napa County will conduct a workshop on “Growing Hydrangeas” on Saturday, May 6, from 9 a.m. to 11 a.m., at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Hydrangeas add style and color to the home garden with their variety of foliage textures, bloom shades and size options. Learn about caring for, pruning and propagating hydrangeas for beautiful outcomes. Vigorous and long-lived, hydrangeas reward the home gardener with extravagant results.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.
When clients bring sickly plants to the Master Gardener help desk, we ask about conditions in their garden. How often do they water and what method do they use?
For every inch a plant grows, there is probably an inch of roots holding it in the ground and nourishing it. In my experience, clients often water less than plants need. Ten minutes with a drip system three times a week is usually not enough.
When I was training to become a Master Gardener, our class studied how fast water drains through soil. Dry soil has tension; water moves around the surface until it can work its way into the soil. For a demonstration in class, several large tubes were filled with different soil types: sand, mulch, clay, loam and gravel. We watched water work its way down through each soil type and learned that each level had to be saturated before the water moved to the next level.
The same is true in your soil. For deep roots, water deeply.
Many vegetables develop roots that go three feet deep; several, like tomatoes, can have four-foot-deep root zones. Consequently, that is where the water needs to go.
Last year, Napa County Master Gardener Ray Sittig made drainage slits in gallon-size cans, then sunk a can in the soil alongside each of his tomatoes. He filled the cans with water twice a week, and the water slowly seeped into the soil.
Hardpan is another potential problem. Your soil's hardpan is the layer below the topsoil that is impervious to water. In my garden, it is a couple of feet beneath the surface. Hardpan was formed by clay deposited during flooding. Most of the top couple of feet of soil has had mulch, compost, fertilizer and other amendments added. Water penetrates easily but stops when it reaches the hardpan. I often push a length of rebar into the soil to see how deep it goes before hitting hardpan. In my vegetable garden, I continue watering until the rebar goes in easily.
When preparing to build raised beds, some gardeners dig the soil below the bed and work compost into the soil to break up the hardpan. Then the raised bed with its improved soil is built on top.
When I plant tomatoes, I place plastic on top of the soil to conserve water. This barrier keeps moisture in the soil, warms the soil and encourages growth. I have also used clean cardboard, cutting holes in it for the vegetable seedlings.
After planting, apply mulch to the soil surface to retain moisture. My habitat garden, which I don't irrigate, has a heavy layer of mulch. Because of that moisture-retaining barrier, it is still easy to pull weeds. One reason to remove weeds is to keep them from taking water from the plants you want.
If you have a plant problem, bring it to the Master Gardener help desk (see hours below). During the summer season, Master Gardeners also staff a help desk at farmers' markets and garden centers around Napa County. Please bring your plant sample in a plastic bag.
Workshop: Napa County Master Gardeners will hold a workshop on “What's Bugging You?” on Saturday, June 18, from 9:30 a.m. to 11:30 a.m., at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Understanding pests and blights that affect your vegetables is key to managing them. Squash that doesn't grow, tomatoes with peculiar markings, artichokes full of earwigs, plants that fail to thrive − all these and more will be discussed. Bring your own problems to show and tell and learn how Integrated Pest Management techniques can help. Mail-in/Walk-in registration (cash or check only). On-line registration coming soon.
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.
A tree's heat requirement is the number of hours it needs between bloom and maturity at a temperature above 55°F. ‘Washington' oranges, for example, need 8,000 hours. Perhaps more important, you need to consider the cold hardiness of your choice. Popular citrus, in order of most hardy to least hardy, would include mandarin orange, sweet orange, grapefruit, lemon and lime.
If your property experiences frost, one strategy is selecting a citrus variety that ripens early. 'Satsuma' mandarins are the most cold-hardy citrus and the earliest bearer. They do well in areas that are normally too cold for citrus, and the foliage survives temperatures down to about 22°F.
Spring is the best time to plant citrus in Napa County, after the threat of frost has passed. This schedule gives the tree's roots time to establish before the onset of cold weather. Choose your site carefully, preferably a protected area away from wind with at least six hours of sun each day. When the winter sun is low in the southern sky, the tree will appreciate placement near a sidewalk or wall that radiates heat.
Mulching around your citrus in winter may not be a good idea. Research shows that the soil retains more heat when allowed to absorb daylight sun. Replenish your mulch in the spring.
Cold air flows downhill, so avoid siting your tree in a low spot or on top of a windy hill. You can also protect your tree from wind by espaliering it against a wall or fence. Citrus trees can also be planted in containers that can be moved to a warm spot in winter, but pots are a temporary arrangement. Your citrus tree will need a larger pot every couple of years.
Fertilize mature citrus with nitrogen monthly from April through August. Feed from November through January with a citrus fertilizer, such as 0-10-10. Trees in containers require less fertilizer. Citrus occasionally suffer from a deficiency of micronutrients, such as zinc or iron. As new growth emerges in spring, add zinc or iron sulfate to the soil or try a foliar application of chelated zinc or iron. Iron will increase the juiciness and size of the fruit.
Maintaining a good fertilizing program helps your tree resist fungal diseases. However, over fertilizing will produce excessive foliar growth, making the tree susceptible to other disorders such as bacterial blast. Use insecticidal soap against the common insects that tend to bother citrus, such as scale, leaf miners and mites. Blast aphids with a strong spray of water.
When cold weather arrives, be ready for frost protection. A citrus tree's tolerance for frost is related not only to variety, but also to maturity and the level of hardening it has experienced. Young trees are especially vulnerable. The amount of damage a tree and its fruit suffer depends on the length of time the temperature remains at or below the threshold for that variety.
For example, if the temperature remains at 25°F for four to five hours, 60 percent of the fruit may freeze. Ripe oranges, grapefruits and mandarins start to freeze at 27°F to 28°F and lemons at 29°F to 30°F. With this information in mind, you can understand the value of frost-protection fabric, which affords a few degrees of protection. I have seen homeowners in Napa who have risen to the challenge, devising tenting that is practically an art form.
Water your tree before the temperature dips. A well-hydrated plant is more capable of withstanding frost damage because moist soils hold heat better. Outdoor tree lights (not LEDs)can be wrapped around your tree to provide extra warmth. Wait until spring to prune any frozen limbs.
Free workshops: Napa County Master Gardeners will lead a workshop on “Soils, Mulches & More” on Monday, September 29, from 6:30 p.m. to 8:30 p.m., at the Yountville Community Hall, 6516 Washington Street, Yountville. Learn the importance of soils, amendments and mulching. Understand basic landscape design and plant grouping. Napa County Master Gardeners will assist with another workshop on “Perfect Plant Picks” on Monday, October 6, from 6:30 p.m. to 8:30 p.m. in the same location. See how a drought-tolerant garden can be colorful and beautiful. Dozens of plants will be on display, including California natives. Both workshops are free but registration is required. To register, call 707-252-4188 X116 or e-mail frances@naparcd.org.
Workshop: Napa County Master Gardeners will lead a workshop titled “Be Successful with Citrus” on Saturday, October 11, at the American Canyon Senior Multi-Use Center, 2185 Elliiott Drive, American Canyon and on Saturday, October 18 in Calistoga at the Community Room, 1307 Washington St. Both workshops are from 9:30-11:30. Get the information you need to succeed with your new or mature citrus trees. Learn about choosing varieties, planting, fertilizing and protecting from frost.Online registration (credit card only); Mail-in registration (cash or check only).The workshop will be repeated on Saturday, October 18, from 9:30 am to 11:30 am. Register online for the Calistoga workshop.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( 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.
