By Okhoo Hanes, U. C. Master Gardener of Napa County
The olive tree (Olea europaea) is well suited to Napa Valley. The tree's Mediterranean origin makes it a natural fit for our sunny, arid and temperate climate. Our warm summers encourage fruit growth, and winter provides the necessary 200 to 300 chill hours (hours under 45°F). The olive tree is frost-resistant, withstanding temperatures down to 15°F.
Rich soil and fertilization improve fruit yield, but the olive tree tolerates poor soil. Deer do not like olive leaves, fortunately, as many a plant in the Napa Valley succumbs to their voracious appetite.
Once established, olive trees require little or no water. Still, deep watering every other week in a hot summer results in better fruit production and helps sustain the tree during drought years. Generally, a rainy winter will almost fulfill the tree's annual watering needs, unless your objective is a good fruit crop.
Extreme weather does not appear to affect olive trees drastically. Even so, growing olive trees in the Napa Valley is not entirely trouble-free.
The olive tree can be grown for both culinary and ornamental purposes. Raw olives are not edible but you can cure them or press them for oil. Branches make beautiful wreathes. In landscaping, the silvery-green olive tree contrasts nicely with dark green redwood trees and the brighter greens of oaks.
The olive tree is evergreen, low care and drought tolerant. Due to this generally unfussy habit, it makes a suitable accent patio container tree, a privacy screen or even a hedge. Dwarf varieties tend to reach six to eight feet in height, adequate for a hedge. But standard varieties can reach 30 feet in height and width. With close spacing and systematic pruning, they can create a tall, dense barrier. Olive trees in containers will need regularly watering to maintain moisture levels due to their limited root zones.
If you are growing olive trees purely for ornamental or hedging purposes, consider a fruitless variety. Then you can avoid the hassle of harvesting or cleaning up fallen fruit, the patio staining caused by dropped fruit and the necessity to spray for olive fruit fly. Fruitless varieties include Swan Hill, Majestic Beauty, Wilsonii, Bonita and Little Ollie, a dwarf type topping out at about eight feet. Although Swan Hill produces neither pollen nor fruit, other fruitless varieties may produce tiny flowers and fruit occasionally.
If you would like to cure olives, you can find a detailed recipe online from the University of California Cooperative Extension (http://anrcatalog.ucanr.edu/Details.aspx?itemNo=8267 ). Or plan to attend the U. C. Master Gardeners of Napa County food-preservation workshop on July 27 (details below).
If you would like to press your olives for oil, some commercial facilities such as Jacuzzi Winery in Sonoma accommodate home growers with small production by aggregating the fruit for pressing. For current information about local olive-mill options, contact the Master Gardener office.
Popular olive varieties for oil include Arbequina, Mission, Manzanillo, Sevillano and Frantoio.
Depending on the variety and when the olives are picked, the oil can range in flavor from peppery to buttery. Before planting olive trees for oil, educate yourself about the flavor differences. Many wineries that grow olives offer olive oil tastings and many specialty-food markets carry varietal olive oils.
Olive fruit fly is the most common pest of olive trees in the Napa Valley. It lays its eggs in the fruit, rendering the olives unusable. Do not add damaged fruit to your compost pile; discard the olives in a brown yard-waste bin. The fly was first found in Napa in 2001 and is now ubiquitous throughout the county. Preventing or minimizing the infestation is critical to slowing its spread.
If you have fruiting olive trees but don't care about harvesting the fruit, spray trees with a plant growth regulator containing ethephon (available in many nurseries) in May or June to prevent fruit set. Alternatively, water the trees with a high-pressure hose during flowering. If your trees do produce damaged fruit, harvest it and discard it. Be sure to pick up any fruit on the ground as well.
If you do want the fruit, spray trees with Spinosad, an organic control, following manufacturer's directions. Harvest early in November and pick up all fallen fruit.
The University of California website has excellent information on growing olives in the home garden. (http://homeorchard.ucanr.edu/Fruits_&_Nuts/Olive/). Paul Vossen, an olive authority and former UC farm advisor for Marin and Sonoma Counties, produced a detailed slide presentation on olive cultivation, titled “Olive as a New Crop” (http://cesonoma.ucanr.edu/files/27719.pdf). Although intended for commercial producers, the presentation's content should be of great interest and usefulness to home gardeners as well.
Workshops: U. C. Master Gardeners of Napa County will hold a workshop on “Growing Olives” on Saturday, July 14, from 9:30 a.m. to 11:30 a.m. Location will be provided after registration. Would you like an olive tree or two in your garden? Olive trees are an attractive evergreen and can provide fruit when properly cared for. Learn what to do in every season to have a healthy tree and tasty harvest. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).
U. C. Master Gardeners of Napa County will hold a workshop on “Freezing and Dehydrating” on Saturday, July 21, from 9:30 a.m. to 11:30 a.m., at Napa Farmers Market, 195 Gasser Drive, Napa. Freezing and dehydrating are ways to preserve your summer bounty in its prime, whether you have too much ripe at once or simply want to get a head start on stocking up for winter. Join UC Master Gardeners as they discuss the benefits of each method and some different ideas for snacks and pantry staples. The workshop is free but registration is required. Online registration.
U. C. Master Gardeners of Napa County will hold a workshop on “Basic Food Preserving” on Saturday, July 27, from 10 a.m. to noon, at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Canning, freezing and drying are among the most basic food preserving methods. It is important to practice safe methods and to stay up-to-date with the most reliable d information about food safety. Master Food Preservers will discuss each process, the equipment required and hazards to avoid, and give demonstrations and recipes. Online registration (credit card only); Mail-in/Walk-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, 707-253-4221, 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 Okhoo Hanes, U. C. Master Gardener of Napa County
The Big Island of Hawaii has captured media attention lately with the spectacular Kilauea volcano eruptions and magma flowing into the Pacific Ocean. The calamity destroyed many homes, numerous residents were evacuated, and communities disappeared or were severely diminished. Such a powerful geological phenomenon humbles us and drives home how fragile our lives are.
Yet life goes on in Hawaii, away from volcanos. Daily chores persist. In Hawaii as elsewhere, gardening helps people regroup and recharge.
In this article, I would like to share how many Hawaiians create beauty with tropical plants in a compact landscape.
The State of Hawaii consists of eight major islands with approximately one and one-half million people. Two-thirds of them reside on the island of Oahu, a modern metropolis with a bustling international airport and robust shipping industry.
Due to its population density, the Island of Oahu has the most urban trappings and suburban communities, to the chagrin of some who lament the loss of the Old Hawai'i. However, Hawaiians in the suburbs manage to preserve the spirit of aloha and Hawai'i in their pocket-sized landscaping.
When they put up fences to define their property boundaries, Hawaiian homeowners often build out little planting beds in the corners, on the outside perimeter. These “pocket” gardens face the street, allowing their creators to share their tropical landscape vignettes with other residents and passersby.
Perhaps these pockets gardens are also an attempt to memorialize some of the land lost to development. Their creators perpetuate aloha spirit by replicating verdant tropical scenes in miniature. Some of these tiny gardens resemble oversized flower arrangements.
These pocket gardens are not much larger than some garden containers, so ideas that work for container gardens work in these pocket gardens, too. To create a pocket garden in the Hawaiian style, you need soil with good drainage. You can purchase potting or gardening soil or amend your native soil with compost and organic nutrients.
Place the tallest plants in the back, medium-height plants in the middle and low-growing ferns, groundcover or cascading flowers or ivy in the foreground. If your pocket garden is free-standing and not against the fence, a showy palm or tree can be centered, surrounded by ferns and shrubs of lower height and a groundcover.
The tropical pocket garden can be adapted for Napa Valley, although it will need more watering. In Hawaii, frequent tropical squalls and showers pretty much negate the need for regular watering of established plants except in rare hot spells without rain. Drought tolerance is not a major issue in Hawaii. Still, authorities encourage xeriscaping for water conservation.
In Napa Valley, however, drought tolerance must remain a foremost concern in landscaping. If you love the tropical look, you can find tropical plants adapted to Napa Valley's Mediterranean climate, but they tend to require regular watering.
Whether you're gardening in Hawaii or Napa, it's critical to put plants with similar water needs together. Add a thick layer of mulch around plants to help retain soil moisture.
The following plants are relatively easy to care for and will give your garden a tropical look. For frost-free palms, consider Alexander palm, king palm, cascade palm, cat palm, triangle palm, cane palm, umbrella palm, Kentia palm, Macarthur palm and sago palm. For broadleaf plants, consider taro, elephant's ear and Japanese aralia. Colorful shrubs to consider are croton, heliconia (lobster claw), bird of paradise, phormium and bromeliad. For flowers, choose canna (although it's thirsty), lantana or angel's trumpet. Suitable groundcovers include aptenia, philodendron and various ferns and succulents.
Local nurseries offer many more varieties suitable for Napa Valley. Consult a knowledgeable nurseryperson about the best choices for you.
Workshop: U. C. Master Gardeners of Napa County will hold a workshop on “Growing Olives” on Saturday, July 14, from 9:30 a.m. to 11:30 a.m. Location will be provided after registration. Would you like an olive tree or two in your garden? Olive trees are an attractive evergreen and can provide fruit when properly cared for. Learn what to do in every season to have a healthy tree and tasty harvest. Online registration (credit card only); Mail-in/Walk-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.
Few other vegetables are more representative of fall than pumpkins. Come October, mounds of pumpkins of various shapes and sizes are a common sight in Napa Valley. While they may seem to suddenly appear, pumpkins have a fairly long growing season. If you are considering growing pumpkins in your garden for a fall harvest, it's time to plant.
Pumpkins belong to a large botanical family that includes melons, cucumbers and other squash. Some tiny pumpkin varieties can fit in the palm of your hand. The record-setting types weigh in at over a ton. Pumpkins also come in shades beyond jack-o-lantern orange. For an unusual addition to your garden, seek out white, red or blue-skinned varieties.
One bonus of planting pumpkins is that they attract bees. Honeybees will happily do the work of pollination, but a garden with a range of plants will lure and nurture other bee species. Squash bees tend to fly early in the morning, before honeybees get going. You may never even know that they have visited your garden. To encourage squash bees, consider adopting a no-till regimen. Squash bees nest several inches below the soil, and frequent tilling can destroy their habitat and nesting populations.
It is a joy to watch pumpkins grow, but they do need space. If your garden has ample room, allowing the plants to ramble can help shade and cool the surrounding soil and prevent weeds from growing. Before planting, amend the soil with compost to get plants off to a healthy start. Plants can be started in small pots or direct-seeded. If you are aiming for maximum size, feed with a high-nitrogen fertilizer to stimulate leaf growth. When blooms appear and fruit set occurs, phosphorus and potassium become more important.
Once established, pumpkins grow fast. To promote larger pumpkins, select one or two good specimens and remove all others on the vine. This pruning will help the plant transfer nutrients to the remaining units.
Squash leaves can be susceptible to mildew. Irrigating with drip or soaker hose is preferable to overhead watering. Remove diseased leaves as soon as possible and do not overwater. Leaves may wilt on hot days but typically recover as the weather cools. If wilting persists, check to make sure plants have adequate water
Common pumpkin pests include cucumber beetles and vine borers. A home gardener can tolerate some damage rather than resorting to chemical sprays. Remember that pollinators and other beneficial insects might be frequenting the plant, too. Use light-permeable row covers to protect plants if an infestation is particularly heavy.
Trap crops can also help reduce insect damage by providing an alternative food source. Crop rotation can help by eliminating available food sources for future generations of pests. The University of California's Integrated Pest Management database is an excellent resource for pest- and disease-control advice.
Besides being delicious, pumpkins have other advantages for the home gardener. They can help minimize weed growth around taller plants such as sunflowers. Native Americans understood the wisdom of planting pumpkins with beans; the beans add nitrogen to the soil and pumpkins are heavy feeders. Many pumpkins store well and can provide tasty meals in winter when many vegetables are out of season.
You don't have to wait for the pumpkin to mature before enjoying the plant. The leaves are edible and can be cooked like spinach. Choose young, tender leaves for that purpose. Of course, the seeds are edible, too. Enjoy them roasted and salted to increase the food value of your crop, particularly if you have limited space. Saving seeds and swapping with friends can increase your garden's diversity with no extra expense.
Pumpkins grow well in Napa Valley. Consider planting a beautiful heirloom cultivar to enjoy as a table centerpiece in winter. Between the pumpkin's tasty flesh, its seeds and its nutritious leaves, this plant hits a triple.
Workshop: U.C. Master Gardeners of Napa County will hold a workshop on “Succulent Plant Success” on Saturday, July 7, from 9:30 a.m. to 11:30 a.m., at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Bring your love of succulents to this workshop dedicated to helping succulent gardeners grow the show-stopping plants we all hope for. Master Gardeners will show you the right kind of soil and containers and how to care for your succulents. They will also discuss myriad succulent types to help you make a succulent garden for yourself or to give as a gift. Please bring succulent cuttings you would like to share.Online registration (credit card only); Mail-in/Walk-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.
By T. Eric Nightingale, U.C. Master Gardener of Napa County
Gardening and a love for nature is on the rise these days. Many people I know would like to garden more but believe they can't because they live in an apartment or have only a small yard. That's not so. While they may not be able to have massive oaks or cultivate long rows of tomatoes, there are still many ways to grow plants.
The first task in any small space, be it a balcony or yard, is to understand the microclimate. Small yards are often protected from the elements by overhanging roofs and fences, while balconies may be more exposed to wind and rain. Study where sunlight hits your growing space. Spend a day at home watching the patterns of sun and shade as the day progresses.
Even if you have only a small yard, you can increase your growing capacity by using containers. Because they're mobile, you can “go vertical” and put them on shelving or place them in spots that would normally be impractical as a growing space. Think creatively
about where your containers can go.
Most plants, properly cared for, will do well in a container for a while at least, but they may require extra attention to keep them healthy. From personal experience, I recommend firm resolve and objectivity during the plant-selection phase. It can be easy to talk yourself into attempting to grow a cactus on a shady patio or a fern on a baking-hot balcony. In the end, both you and the plant will be unhappy with the situation.
When planting in containers, choose an appropriate potting mix. Soil pulled from your yard or garden will likely be too dense. Commercial potting mixes contain perlite and other porous ingredients that enhance aeration and drainage. If you fill a container with garden soil, the soil will settle over time and become compacted, eliminating pore space.
I have seen container gardens that incorporate old charcoal grills, rubber boots, teapots, pasta colanders and paint buckets. If it can hold soil and you can make a hole in the bottom, it can be a planter. For food production, look for food-safe containers. Certain plastics, metals and even woods may leach small amounts of chemicals. This may not be a problem with an ornamental plant, but it is undesirable for edibles. Otherwise, you are limited only by your imagination. Of course, no one will criticize you for just using terra cotta pots.
Compared to in-ground gardening, container gardening presents a few unique challenges, Plants in containers tend to need more frequent watering. Extreme weather conditions also take more of a toll. Plants in containers are more exposed and can't rely on the warmth and water reserves that soil-grown plants can access. In winter I move most of my potted plants against the house to a provide a little more shelter and warmth. Keeping them well watered and covered with frost cloth is also important during harsh winter nights.
One aspect of container planting that caught me by surprise is the issue of water quality. Over time, minerals in the water build up in the soil, sometimes to excess. This buildup is more likely when a plant is not getting thorough watering. To prevent the buildup, deep-water container plants occasionally, watching for water to flow from the bottom of the pot. This tactic will help flush out excess salts and minerals.
If you have a garden hose fed by an in-home filtration system, you may not experience mineral buildup. But if you are using softened water, you may have more problems than expected. Water softeners add salts, which quickly affect plants. One sign of excess salts and minerals in a container is a whitish crust on the soil surface.
I see this buildup in my houseplants, which are lightly watered and never exposed to rain. Poor plant health also signals soil problems. Excess salts can cause a pH imbalance, which can keep the plant from absorbing nutrients. Adding fertilizers, which contain salts, may only make the problem worse. In fact, fertilizer can also build up in containers and should be occasionally flushed as well.
Container gardening offers flexibility and the potential for creativity. It's a hobby anyone can enjoy.
Workshop: Napa County Master Gardeners will hold a workshop on “Culinary Herbs and Cocktail Garnishes” on Saturday, June 23, from 9:30 a.m. to 11:30 a.m., at Central Valley Hardware, 1100 Vintage Avenue, St. Helena. The workshop will be repeated on Sunday, June 24, from 1 p.m. to 3 p.m., at Yountville Community Center, 6516 Washington Street, Yountville. Plant a plethora of herbs to add color and delight to your plate and to your beverages. Cilantro, basils, thymes, mints and their flowers, nasturtiums, roses, pansies, borage and calendula are only the beginning. Learn to grow these useful plants. Demonstrations and hands-on activities add to the fun. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment). To register for the Yountville workshop, call the Parks & Recreation Department at 707-944-8712 or register online.
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.
- Author: Gayle Nelson
When we look at a plant or tree, the bright foliage, tempting fruit or majestic stature might be the first thing we notice. But quietly humming along are the root systems that make all of these things possible.
Most roots live below ground and are difficult to observe firsthand. However, they possess incredible abilities. A closer look at these marvelous plant structures can enhance our appreciation of them.
Roots absorb water and other nutrients to nourish the entire plant. Some have microscopic hair-like structures that penetrate deep into the smallest spaces, increasing the surface area and reach of the main root system. These fine root hairs may also team up with organisms in the soil such as beneficial fungi and bacteria. They can help the plant survive and thrive in changing conditions. Ground-hugging species such as chamomile help anchor and stabilize plants in the soil.
Densely rooted systems form tight connections that can hold soil particles together. Gardeners faced with eroding soils and steep slopes might consider plants of this sort. Some species, such as mesquite, have roots that plunge dozens of feet deep in search of nutrients. While annuals and yearly vegetable crops might be content with the first few inches of soil, deeply rooted vines and trees need more depth to thrive.
Roots also store sugars and starches. Familiar examples include carrots, beets and potatoes. Each of these vegetables is known for its ability to be stored for a long time. Nutrients stored in these roots help feed future leafy plants.
Grafted trees and vines such as apple trees and grapevines sometimes produce small shoots at the base or even some distance away. These “suckers” are from the rootstock. Keep this habit in mind when siting new plants in your landscape. Grafted plants and trees with vigorous rootstocks may wreak havoc.
You have probably noticed the aerial roots on orchids and spider plants. These roots typically grow above-ground and can serve as an anchor or structural point. Epiphytes—plants that rely on other plants for support but not for nutrients—are common, low-care houseplants and may be a good option if you have limited space or time.
The science of roots is still unfolding. To get the most out of the roots in your landscape, be sure to have a plan before planting trees or other root-intensive species. Soil, nutrient availability and the cultivar can determine how easily roots become established. If you have compacted or heavy clay soil, amend it before planting.
Roots compete for space and nutrients, so putting plants too close together can limit growth of some species. Some roots, such as black walnut roots, exude chemicals that keep other plant roots at bay. Think carefully choosing such plants for your landscape.
Before planting perennials or trees, consider how their roots will manage in the event of drought. Extensive root systems too close to sidewalks can also cause problems. And deep-rooted trees and shrubs can interfere with septic systems and underground water pipes. Keeping these possibilities in mind can minimize future landscape issues and help your garden thrive.
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.