- Author: Emily C. Dooley, UC Davis
Project designed to prevent red blotch and other grapevine diseases
A new, $5.25 million greenhouse is being built on the University of California, Davis, campus to safeguard an important grapevine collection from red blotch disease and other pathogens.
The 14,400-square-foot greenhouse will have a vestibuled entry, be insect-proof and provide another level of disease protection. It is being spearheaded by Foundation Plant Services, or FPS, which provides the U.S. grape industry with high-quality, virus-tested grapevine plant material.
The program serves as the primary source for grapevine plant material distributed to nurseries under the California Department of Agriculture's Grapevine Registration and Certification Program, which provides the majority of grapevines planted in the United States. For the grape industry, it is essential to protect this material from disease-carrying insects and guarantee fast access to clean plant material.
“The program is considered the largest quarantine center for the grapevine industry in the United States,” said Maher Al Rwahnih, a plant pathologist and FPS director. “This is kind of a game changer for us.”
A history of serving the grapevine industry
FPS has maintained healthy grapevine planting stock on the UC Davis campus for more than 70 years in open fields at the Classic and Russell Ranch foundation vineyards. FPS scientists first detected grapevine red blotch virus at Russell Ranch in 2017. By 2021, an estimated 51.6% of the crop there was infected. Material from that vineyard is not being sold, and the site is now part of an epidemiological study to try to pinpoint how the disease is transmitted.
FPS pathologists have detected red blotch on less than 1% of the Classic vineyard crop. But it may not always be that way in the future.
“We don't know how long the Classic vineyard will remain clean,” Al Rwahnih said. “Every testing season, this is what keeps me up at night. We're not sure why it's happening in Russell Ranch and not the Classic vineyard.”
Once the greenhouse is operating, grapevines propagated from plant material from the Classic vineyard will be moved into the greenhouse, tested and verified as clean from disease. From there it will be sold to nurseries, which will grow additional plants to sell to growers.
Two greenhouses part of plan
Normally the foundation has 4,000 vines available, but the greenhouse will only house 2,000 vines, so inventory will be cut in half.
“This phase is just a starting phase,” Al Rwahnih said. “It's not sufficient for our needs.”
FPS plans to build another greenhouse in the next two to three years to increase capacity.
Industry groups and FPS identified greenhouses as the best way to protect the plants from red blotch and other pathogens transmitted by insects. They are also consulting with those same people on the grape varieties to include in the greenhouse.
“We have a large selection, and we need to make sure all the varieties that are important to industry are contained,” he said.
The first greenhouse is expected to be finished by the end of 2023.
Funding for the first greenhouse is coming from a variety of sources. The California Fruit Tree, Nut Tree and Grapevine Improvement Advisory Board, managed by the California Department of Food and Agriculture, contributed $4 million to the project. The California Grape Rootstock Research Foundation gave $500,000, Foundation Plant Services with UC Davis is funding $450,000, and the California Grape Rootstock Commission gave $100,000.
“This is crucial for the grapevine industry, and we are very grateful for the support,” Al Rwahnih said.
/h3>/h3>/h3>- Author: Emily C. Dooley, UC Davis
Study explores cooling benefits of fast-growing vines as trees take their time
Perhaps trees aren't the only green solution when it comes to cooling urban spaces and reducing energy costs. Honeysuckle, Virginia creeper, pink trumpet and other vines could be a fast-growing substitute in climate-smart cities of the future.
Researchers from UC Davis are leading a nearly $880,000 federal grant to study how vines may provide cooling and shade in Western states in less time than it takes a tree to grow tall.
“Vines can quickly shade buildings and reduce energy consumption while trees slowly grow to maturity,” said Alessandro Ossola, an assistant professor of plant sciences who is a principal investigator for the project. “We believe vines can be an effective and cheap measure to help cities accelerating climate change adaptation.”
The grant from the U.S. Department of Agriculture's Agricultural Marketing Service will fund work to plant and monitor at least 10 types of vines on trellises in five locations in different climate zones over three years. California Department of Food and Agriculture is administering the grant.
Using less water
Water conservation will be vital as populations rise, climate extremes become more prevalent and the demand for agricultural and drinking water increases. The goal of this research is to identify vines that can help save energy by providing cooling and reduce the need for irrigated water.
“In addition to rapid growth rates, vines can be easily integrated with structures to maximize potential cooling effects,” said Loren Oki, a Cooperative Extension specialist with Department of Plant Sciences, who is the project lead. “But we need to understand the relationships between low water-use plants and their ability to reduce thermal loads on buildings.”
The vines will be planted, supported by a trellis and watered regularly during the first growing season to establish deep roots and healthy shoots. Over the next two years, the vines will experience low, moderate and high water allocations.
The vines will be rated on aesthetics, foliage quality, floral quantity, pest and disease resistance, appearance and other factors. Thermal images of trellis coverage and other environmental measurements will also be taken to assess shading and cooling potential, according to grant documents.
Many vines can be grown along cables and wire nets that are actually detached from walls to avoid direct contact and still provide shade, Ossola said.
“We want to understand which vine characteristics relate to fast growth, reduced water use and increased aesthetic appeal,” he added.
Outreach and education
The findings will enable recommendations to be developed for regions, planners, the landscape industry and the public. It could lead to plants being designated as “water-wise,” “low-water use,” “energy-saving” or “cooling.”
Extensive engagement and outreach will also publicize the information.
“Climate change is a great opportunity for the horticultural industry to innovate and promote climate-ready plant productions,” Ossola said.
USDA funding supports research across state lines to find innovative solutions to regional and national problems, USDA Under Secretary for Marketing and Regulatory Programs Jenny Lester Moffitt said in a news release announcing this and other grants.
“This year's funded projects will address a range of those challenges, from energy and water saving in vine plants, finding cost-effective solutions for heat tolerance and drought, to addressing food safety risks for produce,” Moffitt said.
Scientists from the University of Arizona, University of Washington, Utah State University and the South Coast Research and Extension Center at UC Agricultural and Natural Resources are contributing to the research and will be overseeing vine sites in their states.
This article is reprinted from the UC Davis College of Agricultural and Environmental (CA&ES) website, where it is titled "Could Vines Be the Answers to Speeding Urban Cooling, Water Reduction in the West?"
- Author: Christine Casey
California native vines
These aren't widely available, so you'll likely need to go to a specialist nursery or plant sale to find these. These are listed alphabetically by genus, and I've indicated if it's deciduous or evergreen. These will all grow through a fence or other support and don't need to be tied.
Not a bee plant, but a larval food source for the native California pipevine swallowtail butterfly. The unusual flowers are attractive to flies and appear in early spring before the leaves. Native to riparian areas in northern California and southern Oregon, it will need regular water and part shade in the garden, although it can subsist on less water but will go dormant in the summer. This plant reaches up to 15 feet and can cover a fence or grow up through a tree.
California morning glory (Calystegia purpurata ssp. purpurata). Deciduous to semi-deciduous. Sunset zones 14-24.
California honeysuckle (Lonicera hispidula). Evergreen. Sunset zones 7-9, 14-24.
This plant is used as either a vine or a groundcover. It differs from the more commonly sold non-native honeysuckles in that the pink and white flowers are more subtle and not fragrant. This spring-bloomer is attractive to many bees -- including honey bees, carpenter bees, and bumble bees -- and is also used by hummingbirds. Grow this low-water plant where the roots will be shaded but the foliage will be in sun. Looks best with a few deep waterings over the summer.
Non-native vines
These are more commonly available than the natives listed above and add additional bloom time and interest to the garden.
Purple lilac vine (Hardenbergia violacea) 'Happy Wanderer'. Evergreen. Sunset zones 8-24.
This Australian native blooms in late winter and early spring. It needs moderate water and full sun, and will need to be tied or otherwise supported as it begins to grow. Thin the stems after blooming to prevent it from becoming too tangled. The small purple flowers are attractive to honey bees.
Passion vine (Passiflora cultivars). Evergreen to semi-deciduous. Sunset zones 5-9, 12-24.
These vigorous South American natives will grow quickly to cover a fence or pergola in one season. Due to this growth habit it has become invasive in Hawaii. While the leaves can look a bit tattered by late summer, the flowers put on a spectacular show. It's the larval food source for the gulf fritillary butterfly, so it brings the colorful non-native adult butterfly to the garden. This vine will need to be tied to a sturdy structure to get it going, but once it starts it will provide fast cover. It needs regular water and full sun to light shade. There are many cultivars available with flowers in varying colors from blue to white. In addition to honey bees, we routinely see carpenter bees using this plant at the Haven.
Wisteria (Wisteria sinensis). Deciduous. Sunset zones 3-24.
Next to star jasmine, this very vigorous grower might be the most commonly used vine in the Sacramento region. Just be prepared to give it a very sturdy structure! This Chinese native needs only moderate water and full sun. We grow the cultivar 'Cooke's Purple' at the Haven, as it re-blooms (although not as spectacularly) in July. It is used by larger bees like carpenter bees and bumble bees.
This plant has become invasive in the southeastern US, where the more restrained native Wisteria frutescens is a better choice.
- Author: Gerry L Hernandez
Perennial Berries and Vines
- Blackberries and Raspberries - Don't let the vines get away from you. Thornless varieties are available. I have a blackberry bush that does not get much water so it stays small. It is like heaven when you eat blackberries from your own vines.
- Blueberries – Full sun, choose southern highbush varieties. Varieties from Maine will not work here. Needs soil to stay moist, so mulch heavily. Use acidic fertilizer. Great shrub!
- Grapes – Beautiful on an arbor or pergola. We had grapes growing on an arbor when I was a kid.
- Strawberries – A lot of types to choose from. They can be grown as an annual or perennial. They have many diseases and pests.
Fruit Trees
If you are going to plant a tree, why not a fruit tree? Fruit trees are easy to keep small if that is what you want. If you have excess fruit, share with a neighbor. I know I would prefer to get figs instead of zucchini!
- Apples – Many varieties to choose from. Codling moth (the worm in the apple) can be a problem.
- Apricots – Many varieties to choose from.
- Avocados – These can be a hit or miss in our area. Your neighbor can have a very fruitful tree and you get nothing. If you are going to plant an avocado, you will need an A and a B plant.
- Cherries – Need lots of chill hours. They need a pollinizer. Birds love cherries, so you may not get many.
- Citrus – grows well in the valley. Oranges are so cheery in the middle of winter.
- Figs – bears 2 crops a year. These trees can be huge but they are easy to keep small. I have 2 fig trees in my yard.
- Kiwis – great on an arbor, pergola or trellis. Be careful what variety you purchase. Some are self-fruitful and some are not.
- Olives – loves our hot dry summers. They are a beautiful landscape tree.They do have a problem with olive fruit fly.
- Peaches and Nectarines – one of the easiest trees to grow here. Lots of varieties! Need to spray for peach leaf curl. I have 2 nectarine trees. One ripens in July and the other in August.
- Pears and Asian Pears– need winter chill. They need a pollinizer trees. Pears have a problem with fireblight.
- Persimmons – Make sure you get the kind of persimmon you want (eating or baking). Beautiful fall foliage.
- Plums – Lots of varieties, sizes and colors.
- Plum Hybrids – Many to choose from and many different flavors. My favorite is the green pluot that comes from a prune variety.
- Pomegranate – Can be a shrub or tree. Beautiful flowers and leaves.
Help for the Home Gardener from the CCMG Help Desk
Client Question:
The client was at the Shadelands Farmers' Market in Walnut Creek and made contact with the “Ask A Master Gardener" table. They wanted some information on planting a suitable vine for this area that could be grown on a trellis. They would prefer a California native. The vine will be in full sun. The AAMG table provided some guidance and also passed the question along to the Help Desk to provide a more complete answer.
Master Gardener Help Desk Response:
We are blessed with a large number of vines that grow well in Contra Costa County. The Contra Costa Water District website “Gardening in Contra Costa County, Guided Plant Search” (http://www.contracosta.watersavingplants.com/search.php) lists 57 low-water using vines which do well in full sun. The UC Davis Arboretum All-Stars website (http://www.arboretum.ucdavis.edu/arboretum_all_stars.aspx) also lists several low water-using vines. On both websites, each vine is accompanied by a picture and description. The choice can be daunting! There are many personal preferences to be considered when selecting a vine: do you want an evergreen vine (has leaves year-round) or a deciduous vine (loses leaves in winter); what color flowers do you prefer; do you want fruit; and how vigorous a grower?
Because I don't know if your trellis is on a fence or is a free-standing arbor, I will list a few of my favorites which could be used in either location.
- California Grape (Vitis californica ‘Roger's Red') is a fast-growing deciduous native California grape, or at least a hybrid with a native, which has the benefit of being rather drought tolerant, needing deep watering every 2 weeks or less when planted in the ground. California Grape is a pretty aggressive plant and once established will want to reach out and grow wherever it can. I have this vine growing on a large arbor to provide shade. This selection is also well known for its glorious red/orange leaf coloration in the fall. It does produce grapes about the size of raisins, edible but not exactly fulfilling….maybe small batches of jams? And you might want to give consideration to where the grapes fall as they will be something of a nuisance if they are stepped on and carried into the house. You will also become close friends with the neighborhood's birds and squirrels.
Violet or Lavender Trumpet Vine (Clytostoma callistegioides) is an evergreen non-native vine with large lavender trumpet shaped flowers in late spring to summer, a low to very low water user, and also on the UC Davis All-Stars list.Lilac Vine (Hardenbergia violacea) This a vigorous evergreen vine originally from Australia with purple pea-like flowers in late winter to early spring, a low water user, and also on the UC Davis All-Stars list. You would probably want to prune this vine back annually to prevent tangling. There are also varieties with white ('Icicle') and pinkish purple flowers ('Happy Wanderer' and 'Canoelands'), although I don't know the local availability. The purple flowers are usually widely available. This vine makes a glorious show when in bloom and will cover a long fence top to bottom. You can ask my neighbor.Carolina jessamine (Gelsemium sempervirens) is a beautiful evergreen non-native vine with yellow flowers and shiny green leaves. This vine needs regular water when young, but is fairly drought-tolerant once established. One caution -- all parts of the plants are poisonous if eaten.Chilean jasmine (Mandevilla laxa) is a deciduous non-native twining vine with white funnel shaped flowers in summer, low water user, and also on the UC Davis All-Stars list. This vine shouldn't require much pruning.
Looking at each vine's characteristics, you can decide for yourself which will be the best for your garden. Any choice you make will be a good one and one you will enjoy for years.
Good luck!
Contra Costa Master Gardeners Help Desk
Editor's Note: The Contra Costa Master Gardener Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523.
We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, and we are on the web at http://ccmg.ucanr.edu/