Master Gardener News Blog
By Linda Lewis Griffith UCCE Master Gardener
“Why are the blossoms and leaves on my apple tree turning brown? Deb R. Arroyo Grande
Your tree may be infected with fire blight.
Fire blight is a common and frequently destructive bacterial disease that affects pome fruit trees and other related plants. Pears and quince trees are highly susceptible. Apples, crabapples and Pyracantha species can also be susceptible to damage. Fire blight infections may destroy limbs and even entire shrubs or trees.
Fire blight is caused by a bacterium, Erwinia amylovora, that overwinters in cankers on twigs, branches or trunks of host trees. Warm, daytime temperatures between 75 and 85 degrees interspersed with intermittent rain or hail create ideal conditions for bacteria to thrive. Splashing rain or insects transmit pathogens to nearby blossoms or succulent new shoots.
Symptoms first appear in spring as trees begin to grow. A watery, light tan liquid oozes out of infected areas. The ooze darkens after exposure to air, leaving streaks on branches and trunks. Cankers may be inconspicuous and go unnoticed until later in spring when flowers, shoots and young fruit shrivel and turn black.
Vigorously growing shoots are the most severely affected; conditions such as high soil fertility and abundant water increase the severity of damage.
Management begins by first selecting varieties of plants that are less prone to damage. For instance, Fuji, Gala, Golden Delicious, Johnathan, Mutsu, Pink Lady and Yellow Newtown are susceptible to fire blight; Empire, Pristine and Williams Pride are considered more resistant.
Once infections have taken hold, it is necessary to prune out diseased branches. Cut infected branches at least 8 to 12 inches below the visible injury or canker. A greater distance below infections may be required on major branches, scaffolds or trunks in May or June when fire blight bacteria are moving rapidly.
To avoid spreading bacteria during the pruning process, dip or spray pruning tools with a 10 percent solution of bleach (one part bleach to nine parts water) before each cut. Dry and oil tools after use to prevent rust.
For more information about fire blight, visit these websites:
All Things Citrus
By Tami Reece UCCE Master Food Preserver
What can I do with all my extra lemons from my garden? Ann B. Nipomo
San Luis Obispo County gardeners are very lucky because with a little frost protection we can grow citrus throughout the winter season well into summer, depending on the varieties. And the best way to extend the citrus season even further is to preserve your harvest. Preservation methods can include pickling, freezing, dehydrating, or canning. On Saturday March 25, 2017, the UCCE Master Food Preservers will have an “All Things Citrus” preserving workshop to show you how. A variety of citrus subjects will be discussed but one of the more unique recipes that will demonstrated is salt preserved lemons. It is a process of salting lemons and preserving in their own juices for up to 30 days. This is a very easy process that results in creating a unique flavorful pickled taste with a wonderful silken texture. They are great in salads, salsa, dips, chicken, lamb, and pasta dishes. You will also be shown how to make lemon curd, a decadent creamy delight that can be used in pies, desserts, pancakes, and even oatmeal but it never seems to last until the next morning at my house! Finally safe methods to store, preserve, and enjoy oranges will be discussed, as well as marmalades.
The workshop will be held in the auditorium adjacent to the parking lot at 2156 Sierra Way, San Luis Obispo, 10:00 a.m. to 12:00. There will be a $5.00 charge to cover class supplies and you must register at http://ucanr.edu/survey/survey.cfm?surveynumber=19887 as space is limited.
If you have any questions regarding the class or general preserving questions regarding water bath canning, pressure canning, freezing, or dehydrating, you can call our UCCE Master Food Preserver Helpline at (805) 781-1429 and leave a message or email the UCCE Master Food Preservers at email@example.com. A UCCE Master Food Preserver is available every Wednesday from 1:00 to 3:00 to assist you with your questions.
To view seasonal preserving recipes, food safety information, articles on food preservation, or other classes available in 2017 from the UCCE Master Food Preservers visit http://cesanluisobispo.ucanr.edu/YouthFamilyCommunities/Master_Food_Preserver_Program/
By Leonard Cicerello UCCE Master Gardener
I would like to learn to propagate my own plants, any suggestions? Carol M. Arroyo Grande
Propagation, the art of multiplying plants, is one of the most rewarding challenges that a home gardener can undertake. Propagation techniques take many forms, but all involve using plant parts to create a new plant.
First, there is seed propagation which requires the correct light, heat, and humidity to be successful. Methods of asexual propagation include cuttings, layering, budding, and grafting. Cuttings are defined by softwood, semi hardwood, and hardwood. Each plant species has a particular time that's best for successfully rooted cuttings. Asexual propagation uses the leaves, stems or roots of a parent plant to create a new plant.
Layering can happen naturally when a lower branch of a shrub grows along the ground, maintaining contact with the soil while the tip of the branch is pointed upward out of the soil. The section in or along the soil will root. You can snip off the branch that has formed roots and plant it in a pot. The same feat can be accomplished intentionally above ground with the method referred to as air layering. Make a surface cut on a branch, enclose the wound with moistened moss, and then wrap plastic around it. In time, it will form roots.
Propagation by grafting enables you to combine different varieties of citrus or stone fruits on a single tree creating what's often called a fruit cocktail tree. Tomatoes plants also lend themselves well to grafting.
Another method is propagation by division. The group of plants referred to as bulbs, which includes bulbs, corms, rhizomes, tubers and tuberous plants, are propagated by division. For maximum productivity, dig them up annually, divide them and replant them. You may have multiple cymbidium plants in a single container. To maximize its growth and beauty, remove the entire clump from the container, divide the plants, and replant each in a separate container.
For additional information on seed propagation, tomato grafting, and cuttings, register to attend the Master Gardeners Advice to Grow By workshop set for March 18th, from 10:00 am to 12:00 pm at the Garden of the Seven Sisters in San Luis Obispo. Head to our website to register - http://ucanr.edu/sites/mgslo/.
By Leslie E. Stevens UCCE Master Gardener
With all this rain, I can't wait to start planting. Any suggestions? Mary B. San Luis Obipo
This spring will be a time to celebrate! Winter rains have not only greened our landscapes and filled our reservoirs, but leached salts from our soils and nourished our plants after six years of punishing drought.
And what better way to celebrate than planting a spring garden! Our county enjoys a long growing season -- March through November in warmer parts of the county, and April through October in colder North County and interior valleys. The following are tips to get you started.
Trees & Shrubs – While autumn generally is considered the favored time to plant many trees and shrubs, subtropicals such as citrus and avocados are exceptions. Plant these frost-sensitive trees in spring so they become well established before facing next winter's chill.
This month is the last chance to plant bare-root trees and shrubs in cold winter areas.
Fruits & Vegetables
March is your earliest opportunity to plant perennials such as bay, oregano, sage and yams, as well as artichoke and asparagus crowns and rhubarb rhizomes. Wait until April to plant veggies, fruit and herbs such as corn, cucumbers, eggplant, fresh bean, horseradish, peppers, potato, pumpkins, summer squash, tarragon, thyme, tomatoes, watermelon and zucchini. Likewise, you can start seeds indoors now for many warm-season crops and transplant outdoors in 6-8 weeks.
March is also the last opportunity to plant cool-season crops such as beets, carrots, chard, kale and lettuce outdoors.
Flowers & Ornamentals
Plant bulbs, rhizomes and tubers of perennials such as agapanthus, amaryllis, cannas, dahlias, daylilies, bearded and Dutch irises, and gladiolus for spring and summer color. Local nurseries should have an increasing stock of spring annuals, flowering perennials and shrubs. Look for drought-tolerant favorites such as sweet alyssum, cosmos, coreopsis, gaillardia, lavenders, Indian Hawthorne, scabiosa and yarrow.
Before heading to the nursery, make sure to weed planting beds and amend soil with compost or organic fertilizer to give new plantings a healthy start. Install drip irrigation if you haven't already done so. You're now ready to plant, apply mulch and enjoy the future fruits of your labors.
Visit http://arboretum.ucdavis.edu/arboretum_all_stars.aspx for a list of 100 plants recommended for California gardens by staff of the UC Davis Arboretum.
Brown Rot on Citrus
By Andrea Peck UCCE Master Gardener
What are the brown spots on my oranges? Margot S, Arroyo Grande
Brown spots or lesions on citrus usually mean one thing: brown rot. Brown rot is a disease that affects all parts of the tree, but is most often observed on the fruit. It is transmitted via various forms of the pathogen, Phytophthora, which resides in the soil. During wet weather, Phytophthora is bounced up from the ground by rain and wind. Continued moisture creates a hospitable environment for growth. Because of the nature of transmission, the lower canopy of the tree is particularly susceptible. In the beginning stages, the infection is not visible to the eye, but as time goes on the site will develop a whitish growth which will inevitably become a round, leathery stain.
Brown rot is not just aesthetic--infected fruit has a pungent odor and is generally inedible. It can damage branches, decrease vigor and affect the overall health and bounty of the tree. For the commercial grower, brown rot is a significant issue. Fruit may not show signs of damage at harvest and infected fruit may spread the disease during shipment. In 2013 this problem was so severe that shipping of citrus to China was shut down due to infected fruit. That ban has since been lifted, but a continued system of monitoring remains.
All citrus growing regions of California have Phytophthora and no citrus is immune. Prevention is usually your best bet. Pruning the lower branches so that there is at least 24 inches between the branches and the soil decreases the possibility of infection. Keep sprinklers and hoses away from the tree and apply irrigation directly to the soil instead. Prune the canopy of the tree to allow adequate light and air circulation. Use copper spray in late August and again in October to create a layer of protection. When rains are heavy, an additional application in January may be required. Spray all parts of the tree, including the underside of the leaves, the trunk and the soil below. With a little luck, you'll have a 'fruitful' year!