By Susanne von Rosenberg, U.C. Master Gardener of Napa County
After you have been gardening a while, you may want to branch out and try growing more unusual plants. Being successful with less common plants requires more knowledge and research. Experience helps, too.
Uncommon plants fall into three categories. Some are simply unfamiliar but not difficult to grow, such as watermelons that don't have red flesh. (I like ‘Cream of Saskatchewan,' which has a creamy white interior.) We're all familiar with pluots (a 75 percent plum-25 percent apricot cross), but there are also plumcots (equal parts plum and apricot) and apriums (25 percent plum-75 percent apricot), as well as a cherry-plum cross. All of these crosses can thrive in Napa Valley, but be sure to check the basics before planting them. Does your microclimate provide enough hot days to ripen that watermelon, or enough chill hours for the aprium?
Other uncommon plants may be more challenging because you don't know anyone who has grown them. The jujube (also known as Chinese date or red date) is a fruit tree that at least one Napa County nursery offers in bare-root form. But do you know anyone who has grown one?
For such plants, you need to research the pros and cons yourself. Jujubes have spines on young wood, require unusual pruning techniques and tend to sucker. On the positive side, they thrive in almost any soil, are drought-resistant, have a long productive life (more than 50 years), often fruit within two years of planting and produce nutritious fruit.
Other plants may be rare in Napa County because they are difficult to grow here. They may not like our climate or need more day length than we have. While you can modify climate somewhat (depending on how much time and money you want to invest), there is little you can do about day length.
Plants from equatorial areas are used to a consistent 12 hours per day of sunlight and may not flower or fruit if the daylight period is longer or shorter. Chayote squash tends not to set fruit in Napa Valley until late August or early September, when the days are shorter, and then our growing season is cut short by frost before the squash have time to mature.
Before planting any uncommon plant, find out whether it is invasive in California. A few years ago, I became enthralled with a plant called autumn olive, also known as silver berry. Then I learned that it is considered invasive everywhere it is found. Even so, you can still buy it in nurseries, including on-line nurseries.
Next, think carefully about your microclimate. Consider how much sun or shade the plant requires, how much heat it needs or can tolerate and whether it requires some winter chill. Is the plant frost- or wind-sensitive? What are its needs with regard to humidity? What is its typical growing season, and is our growing season long enough for it to mature fruit?
What kinds of pests and diseases does this plant suffer from in its native habitat, and do we have any of these pests and diseases in Napa Valley? Make sure the plant can thrive in your type of soil and that, when full grown, it will fit in your garden. I was thinking about planting pecan trees until I learned that they typically grow 65 to 130 feet tall.
Finally, think carefully about how much time and money you want to invest. You could grow bananas in a heated greenhouse in our climate. Do you want to spend the money to install and heat a greenhouse?
Do your research using reliable sources such as the University of California Cooperative Extension, other university websites, information from U. C. Master Gardeners, reputable nurseries and other recognized authorities such as the California Rare Fruit Growers or California Native Plant Society. When considering information from other universities, be aware that their recommendations are based on the climate in that region.
Enjoy your explorations and let U. C. Master Gardeners of Napa County know what types of unusual plants you have growing in your yard.
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 Marcy Nielsen-Berruezo, U.C. Master Gardener of Napa County
It happens every year. There's a moment when suddenly I notice that the light has changed. Days are shorter and shadows are longer. Chinese pistache trees begin to turn color and the squirrels in my garden go nuts.
This is the time when savvy California gardeners perk up as it's prime time for planting in our Mediterranean climate. Planting in September and October, while the ground is still warm and rain is on its way (we fervently hope), allows new plantings to establish roots. By settling in now, these new plants will be ready for the flush of growth in spring.
Many California native plants are actually dormant in summer. Fall planting lets you enjoy their emergence from dormancy into winter growth and bloom.
I tend to use my own garden as a laboratory, researching plants and testing them to see how they do. As the drought lingers and we become more aware of the need to support the ecosystem in our gardens (and not just in the wild), I've been increasingly going native.
My goal: A garden that offers year-round beauty with minimal use of resources (water, fertilizer and the sweat of my brow). I also want a landscape that maximizes support for local native flora and fauna, including me.
I've made mistakes. I've underestimated how big a happy native plant can get and I've misjudged what happens when I over- or under-water a native. But I love seeing the change of seasons, the buzz of life and the splashes of color in my garden all year. All I need to do to nurture that rhythm is to clean up twice a year.
Many of us have responded to drought by reducing irrigation or eliminating turf in our landscapes. But drought or no drought, California has arid summers and probably always will. According to the Association of California Water Agencies, more than 50 percent of residential water use takes place outdoors. The federal Environmental Protection Agency estimates that half of that water is wasted by inefficient and unnecessary delivery.
Plants adapted to our rainfall and temperature patterns need little or no irrigation once they're established. The University of California, in collaboration with top landscape professionals and horticulturists, has developed the Water Use Classification of Landscape Species. This online database is a useful tool for determining the actual water needs of the plants commonly used in California landscapes, grouping them by region and type.
The database gives most of our native plants two irrigation designations, one for the cool season and one for the warm season. California mountain lilac (Ceanothus species) is classified as M/L, for moderate water in winter and low water during the warm months. California fuchsia (Epilobium canum) is classified as L/VL, adapted to low water in winter and very low water in summer.
In most settings, an established native plant needs (and wants) no additional water unless winter rain is scarce. Wet soil in summer can trigger oak root fungus (Armillaria mellea) and other soil-borne pathogens that can kill a stressed plant or shorten its lifespan.
A few native plants can tolerate or even benefit from occasional supplemental water in summer, and some enjoy a light hosing off (think summer shower in the foothills) or a deeper drink once a month or so. But don't overdo it. When planting, try to group plants with similar needs for sunlight, drainage and water.
In deciding where to place natives in your garden, picture where they grow in the natural landscape. California has a wide range of habitats and ecosystems, elevations and soils. A plant adapted to a shady streambed or redwood forest will have different needs than one adapted to open oak savannah or dry chaparral. Finding or creating the microclimate they like will help native plants live a long, healthy life.
Native plants have evolved to resist local pests and diseases, reducing the need for pesticides or other interventions. In fact, beneficial insect species have evolved along with the natives, timing their egg-laying and brood-hatching to munch on pesky invaders.
You may need to put up with a few chewed or distorted new leaves until the beneficial species tie on their little capes and swoop to the rescue. A little toleration goes a long way in letting a garden find its ecological balance. If you must intervene, use Integrated Pest Management (IPM) practices for the least intrusive approach. Look online (http://ipm.ucanr.edu/) for the University of California's IPM recommendations.
Consider leaving some seed heads, berries and dormant vegetation to provide food and shelter for over-wintering birds and beneficial insects. You'll enjoy the life and movement in your garden and nature will thank you.
Choose plants that bring year-round interest, varying bloom times or offering winter leaf color and berries. Know each plant's mature size before planting. Less pruning means less work for you, less stress for the plant and less waste in the recycling stream.
Include a diversity of species to more closely mimic nature and make it less likely that pests will thrive. Notice what thrives in your area. If a plant is happy in nature and you can replicate that environment in your garden, you can bring the feel of nature home.
Native Plant Sale: U.C. Master Gardeners of Napa will have an information table at the California Native Plant Society Napa Chapter's plant sale on Saturday, October 15, and Sunday, October 16, from 10 a.m. to 4 p.m., at Skyline Park in Napa. The preview party for CNPS members and guests is Friday, October 14, from 6 p.m. to 8 p.m., at Skyline Park.
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.