By Susanne von Rosenberg, UC Master Gardener of Napa County
Plants are a terrific way to create a privacy screen for your garden, or to create a shady space in summer. For privacy screens, it's typically best to select plants that are evergreen.
The first consideration, as always when selecting plants, is the planting site. What type of soil do you have, and how much sun does the area get? Next, figure out how high you want your privacy screen to be. Do you just need to create a screen between your neighbor's patio and your own? Or do your neighbors look down into your yard from their second (or third) story?
Also consider, especially for taller privacy screens, where the plants will cast shade. If you need a privacy screen on the south side of your property, it may cast shade for much of the year.
Make sure the plant you're considering is not on an invasive-species or noxious-weed list for your area. The California Invasive Plant Council maintains a list of plants that are considered invasive in the state. In general, if a non-native plant reseeds readily and is drought tolerant, it has a good chance of being invasive here.
How fire resistant is the plant you're considering? Are the roots likely to be invasive? Will they affect your neighbor's property or damage sidewalks?
How much maintenance are you willing to do? While fast-growing plants are appealing when you're eager to create privacy, they will also likely take more maintenance.
If you have animals, you'll want to avoid plants that are toxic to them.
If you choose wisely, your privacy screen can provide other benefits, such as fragrant flowers, edible fruit or wildlife habitat. When evaluating potential candidates, make sure you understand their maximum height and width. I was considering fern pine (Afrocarpus gracilior) for a privacy screen at my property (it grows 2 to3 feet per year) until I learned that it can reach 35 feet in height. I need a privacy screen that is 20 to 25 feet tall and do not want it any taller because it would shade too much of my yard. Fern pine is commonly grown as a tall hedge and maintaining it at 6 to 8 feet is certainly feasible. But pruning it to keep it at 20 or 25 feet is not a task I want to take on.
For a low screen of 6 to 8 feet, you have the most choices. You can plant evergreen vines along a trellis, a variety of shrubs, or small trees that you can prune into a shrub or hedge. Traditional options include boxwood and privet hedges, and camellias for a less formal hedge in shady or partially shady areas. Other options include Meyer lemons (they are relatively frost tolerant and have dense foliage); lilac vine (Hardenbergia violacea), a vine with sprays of small, dark purple flowers); and trumpet vine (Distictis sp., either the red-flowered variety or D. buccinatoria, which is hardier). Or consider a native plant such as California lilac (Ceanothus), which comes in a range of blue colors and heights.
If you are installing a trellis or fence near a property line to support your plantings, make sure you know the local zoning and permitting codes. Typically there are limits on fence height.
Taller privacy screens can be more challenging. Typically you will be considering trees with a dense canopy or growth habit. If you select a tree with a relatively wide canopy or spreading growth habit, you will need fewer of them for your hedge. Good options include cypress, arborvitae, redwoods, evergreen magnolias (not all are evergreen), loquats, full-size (not dwarf or semi-dwarf) citrus trees (but consider frost hardiness), and English laurel (Prunus laurocerasus).
English laurel (also known as cherry laurel) is in the same plant family as peaches and nectarines; it is not a true laurel. It received its common name because its leaves resemble laurel leaves.
Again, make sure that your selection suits the site. Magnolia trees range in height from 10 feet to more than 50 feet at maturity. Many a gardener has planted redwoods only to be overwhelmed by their size 10 or 20 years later.
Most people who are interested in creating a privacy screen have heard that bamboo is fast growing. Bamboo is no longer recommended within 30 feet of structures because it is considered fire prone. Nor should it be planted along roads and driveways because it can present a fire hazard to emergency responders. In addition, bamboo can easily get out of control and it requires a fair amount of water.
Choose wisely, and you will have a privacy screen to enjoy for years.
Workshop: “Sustainable Vegetable Growing” (Four-Part Series) on Sundays February 23, March 1, March 8 and March 15, from 2 p.m. to 4 p.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to Online registration (credit card only) or call 707-253-4221.
Workshop: “Step-by-Step Garden Design” on Saturday, February 29, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to On-line registration (credit card only) or
Mail-in/Walk-in registration (cash or check only) or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
By Penny Pawl, UC Master Gardener of Napa County
Over the many years that I have been a Master Gardener, I have heard people talk about Nicotiana in the garden, but I didn't pay much attention. Then fellow Master Gardeners Gary Thompson and Noble Hamilton gave me a Nicotiana plant a couple of years ago. That's when the love affair began.
This plant is a member of the nightshade family (Solanaceae), a group that also includes tomatoes, potatoes, peppers and eggplant. It is one of the largest plant families.
Nicotiana is a showstopper in the garden as it grows about five feet tall and has beautiful blooms on the top of the stems. The white flowers grow in a cluster and they shine. The flowers set an enormous amount of tiny seeds.
Nicotiana's main pollinators are moths which come out at night, when the scent of the flowers is strongest.
In addition to the large white Nicotiana, I have a smaller version with green flowers (Nicotiana alata). It stays about two feet tall and is covered with small green blossoms.
Nicotiana is native to tropical and subtropical areas of North and South America. Some varieties also come from Australia. Although they are tropical, in my garden they have not frozen and are perennials. In cold climates they are treated as annuals and replanted each year.
Nicotiana plants bloom in a range of colors, including pink, pink with white, and rose. The plants are easily propagated by seed, and there are many seed sources online.
The seeds pods contain millions of tiny black seeds. I cut back a Nicotiana plant earlier this year and got countless black seeds in my hair and ears. The leaves are sticky, too, so I had leaves in my hair and ears as well. Luckily, they washed off. After the fires last year, the leaves were covered with soot and other debris floating in the air. That mess did not wash off, but those old leaves were eventually replaced by new ones.
If you deadhead the plant religiously, it will rebloom through summer and into fall. However, I would recommend not putting any of the spent blossoms in your compost pile to avoid spreading Nicotiana everywhere. You might end up with a Nicotiana forest.
The garden Nicotiana (also known as “flowering tobacco”) is related to the tobacco grown for cigarettes, but all parts of flowering tobacco are poisonous.
If you plant Nicotiana in a bed, put it in the middle or rear of the bed. It gets tall and as more branches form, it tends to bend over the plants around it. In my garden it does not demand a lot of water. It gets drip irrigation about once a week and worm compost for fertilizer once or twice a year. When winter arrives, I cut the plant back to about two feet.
If you purchase Nicotiana seed, sow it in seed-starting mix and watch the tiny seedlings emerge. Or you can scatter the seed directly in the planting bed. In either case, you will probably need to thin the seedlings as the plants require a lot of space when mature.
Next workshop: “Sustainable Vegetable Growing” (Four-Part Series) on Sundays February 23, March 1, March 8 and March 15, from 2 p.m. to 4 p.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to Online registration (credit card only) or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
By Denise Seghesio Levine, U. C. Master Gardener of Napa County
Many years ago I read a garden book that explained that the key to growing healthy plants is growing healthy soil. Rather than watering and caring for just my vegetables, I learned I needed to care for and water the entire bed to keep all the living things in it thriving. It was a revelation to me, and my gardening efforts improved significantly when I put this new knowledge into practice.
Healthy soil is functioning soil. Functioning soil sustains biological diversity and microbial activity. It determines how productive and successful our efforts will be.
Healthy soil regulates the percolation of water, acts as a filter to buffer organic and inorganic materials, stores and cycles carbon, provides plant nutrients and keeps rooted plants stable and supported.
Did you know there are more living organisms in a teaspoon of healthy soil than there are people on earth? We have all had the experience of lifting a handful of rich, dark, humusy earth and feeling that it is indeed alive.
Our responsibility to keep it alive and thriving can be a little daunting, especially when half of the planet's soils are currently considered degraded. But protecting and improving soil health is really learning to protect and maintain suitable habitat for the soil food web.
What can you do? First, grow as many different species of plants as is practical in your garden. Look to nature for ideas on how to mix plants and take advantage of all the variety available.
Rotate annual vegetable and flower crops. Avoid planting vegetables from the same plant family (tomatoes and potatoes, for example) in the same spot each year. Rotating crops helps you avoid depleting some soil nutrients and also helps keep pests at bay by disrupting their reproductive cycles.
In Napa County, we are fortunate to have mild-enough winters that we can have something edible growing all year. If you have not yet attempted winter vegetable gardening, consider that growing vegetables in winter is good for your own health and for your soil.
When you are not growing vegetables, flowers or other plants, cover bare soil with cover crops or mulches. In winter, vegetation and mulches protect the ground from the effects of pounding rain, which can not only compact your soil but can also leach or wash away important nutrients. When soil aggregates remain intact, water, oxygen and nutrients can percolate down to nourish your soil, microorganisms and plants. Cover crops and mulches also provide habitat for those members of the soil food web that spend at least part of their time above ground.
One Natural Resources Conservation Service publication advises that if improving soil health is your goal, “you should not see the soil very often.”
In addition to keeping soil cool and moist, mulches such as compost, leaf mold or even straw (ideally, free of weed seeds) can also suppress weeds, especially early in the growing season. Your crops will have less competition when they are young and trying to get established.
To keep your soil healthy or to improve its tilth, disturb soil as little as possible and adopt no-till methods. Instead of uprooting spent plants, cut them at ground level and leave the root systems in the soil to decompose and create aeration paths and food for soil microorganisms.
If you are developing new beds or trying to revive tired, compacted soil, this is a great time of year to apply a few inches of compost or mulch. Perhaps visit the local bait shop for a container of live worms to introduce to your beds and let the winter rains begin your work for you.
Tilling or rototilling is traumatic for your soil. As far as the living organisms in your soil are concerned, the effect is the equivalent of an earthquake, hurricane, tornado and forest fire occurring simultaneously. Gently loosen soils with fork tools and avoiding turning and shoveling. These practices will go a long way toward maintaining the integrity of your soil.
Soil compaction can be a problem in winter. It happens when we walk on wet garden beds, especially when they are still recovering from rain. You have probably noted how hard paths get when walked on daily. Our local clay soil, inundated with water and then compacted by walking, driving, digging or tilling when the ground is wet, becomes hard as a brick. Fine for paths, not the best for growing vegetables and flowers.
Next workshop: “Sustainable Vegetable Growing” (Four-Part Series) on Sundays February 23, March 1, March 8 and March 15, from 2 p.m. to 4 p.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to Online registration (credit card only) or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
By Iris Craig, U. C. Master Gardener of Napa County
January is a month for setting intentions, and many of us set intentions for our gardens. For some of us, the big goal is to be more organized.
How can you improve the organization of your winter garden? One way is to keep a journal. Describe the weather, your maintenance, what you planted and when you harvested. Your journal can include a photo or drawing of the garden for each month. By keeping track of what is going on in your garden, you start to see patterns.
You can also schedule tasks so you complete them at the best time. In most areas of the country, winter is a time when gardens rest. In Napa County, a winter garden can be just as much fun to care for and as productive as in June. Plus, you can turn off the irrigation and allow rain to water the garden for you. Tasks that are best accomplished in winter include replacing your lawn, planting annual flowers for color, planting bare-root trees or shrubs, improving your soil and caring for fruit trees.
Good soil enables plant growth. To preserve your soil structure, refrain from walking on it or tilling it while it is wet.
We can affect climate change through our soil maintenance practices. Soil is an ecosystem itself. It can sequester carbon, making it a carbon reservoir. Over-tilling soil tends to deplete it of organic matter and reduce the ability of plants to absorb water.
To protect and improve your soil, and to sequester carbon, plant a cover crop. Cover crops reduce soil compaction and protect the soil from erosion. They improve soil structure, increase organic matter and fix nitrogen.
Common cover crops include fava beans and other legumes. Legumes add nitrogen, and nitrogen is the main plant nutrient commonly lacking in our soils.
Another good cover crop is lacy phacelia (Phacelia tanacetifolia). It is in the borage family, native to California and grows well. It attracts bees and blooms all winter. Cover crops compete with weeds, often choking them out. However, while the soil is damp, you can easily control weeds by hand.
Should you decide to remove a lawn, now is the ideal time. You can use the lasagna method. Instead of digging out sod, cover it with sheets of cardboard topped with soil and mulch. The rain and soil organisms will do the rest. Within three to four months, you will find rich soil in place of the lawn.
With planning, you can have blooming plants in your garden all year. Choose shrubs that blossom in winter and plant them as soon as the soil is dry enough to work. (It should be crumbly.) Flowers for winter bloom include primroses (Primula vulgarius), violas, Iceland poppies, pot marigolds (Calendula) and sweet William (Dianthus). All will bloom early and tend to last through the rainy season. You can plant them in a container or planter box if the soil is too wet.
If you plan for it in late summer, you can have a winter vegetable garden in Napa County. Suitable vegetables include bok choy, kale, mustard greens and Swiss chard, as well as broccoli and cauliflower. You can also plant root vegetables in early fall for winter harvest; consider beets, carrots, turnips, kohlrabi and radishes.
If you missed this window, begin planning your spring garden. You can start many leafy spring vegetables from seed now and transplant the seedlings into the garden in early to mid-March. Most root vegetables should be sown directly in planting beds.
If you have frost-sensitive plants, such as citrus trees, or want to get a head start on your spring vegetable garden, protect your garden from frost with burlap or floating row cover. Create a frame with plastic tubing to drape the fabric and prevent it from touching plants. Anchor the fabric to the ground to keep out snails and birds. Remove burlap every morning so the plants can receive sun during the day. You can leave floating row cover in place; it warms the soil on sunny days.
To get more organized in your garden, consult the Master Gardeners publication, “A Month-by-Month Guide to Gardening in Napa County.” It makes gardening recommendations for each month and includes a section where you can record important information. The publication is available for purchase in the Master Gardener office (address below).
Next workshop: “Flowers and Foliage for the House, growing Flowers for Bouquets” on Saturday, April 27, from 9:30 to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online Registration go to http://napamg.ucanr.edu or call 707-253-4221
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
While skimming a magazine from England called Permaculture, I found an article about mounding. The article described how to build mounds in your garden and what materials to use. Over time, the soil becomes richer from the decaying materials. Also, the sides of the mounds provide more space to plant. I realized that I have already done this in my own garden.
When I removed my back lawn many years ago and replaced it with mounds, i used the dried turf from the lawn. I turned the sod upside down for the base of each bed, then proceeded to build the beds up with mulch from my own yard; branches, bark and trimmings. On top of the whole thing I added compost and some garden soil.
These beds were created 20 years ago and are still looking good. I have some major plantings on them, such as small maple trees and lily of the Nile (Agapanthus). Annually, I add compost and dried leaves to enrich the soil.
I also created a mound when I gave up on my huge walnut tree. The squirrels were stripping it and dropping unripe walnuts everywhere, including into my fish pond. After much consideration i had the tree removed.
After the stump was out I started to fill the depression with organic materials from my yard. The first layer was sticks and stumps from small prunings around the yard. Then I added leaves and other garden waste and piled soil on top of the whole thing. Since I planted figs on this area, I call it Fig Hill. It also gets annual composting and other soil added to keep the height.
The sticks and other organic materials that I put in these mounds act like a sponge, absorbing water and holding it for the plants. If you have soil that does not drain well or is hard to work, mounds will help with both of these problems.
With both of these experiences, the results repaid the work. Now is a good time to start such a project in your own yard as you prune and clean up in your garden.
As I learned from the magazine article, one approach is to dig long trenches and then fill them with logs, branches, leaves, grass clippings, straw, cardboard, black and white newspaper, cured manure, compost or other available materials. Then you top it all with good soil. Water well and let the soil and materials start to decompose and settle. Then you are ready to plant vegetables or flowers in your mounds.
The organic content of the mounds gives off heat as it decays and keeps the soil warmer. And the decomposing wood gives off nutrients for years. Hard woods will take longer to decay than soft woods.
An added benefit of the mound method is that it doesn't require tilling. No-till gardens are better for the creatures that live in the soil, like earthworms, so, ultimately, they are better for soil health.
Mound gardens also mean less bending for the gardener.
The article recommended constructing steep beds to avoid compaction from foot traffic. Steep beds create more surface area in your garden for plants, and the height makes easy harvesting. The greater the mass, the greater the water retention.
Some of the beds shown in the article had straw on the top and sides to hold the materials in place. Others had wire sides with plants inserted between the wires. One gardener used shipping pallets to hold everything in place with plants planted between the slats.
Next workshop: “Sustainable Vegetable Growing” (Four-Part Series) on Sundays February 23, March 1, March 8 and March 15, from 2 p.m. to 4 p.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to Online registration (credit card only) or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.
