We hope you enjoy this webinar with Maxwell Norton, retired UC Cooperative Extension Advisor for Merced County. Maxwell talks about the history of citrus, how varieties came to be, and how the citrus industry in Southern California became so successful. He also answers questions about pruning, fertilizing, and pests. Citrus Video 

Here are the resources mentioned during the talk.

Citrus varieties
https://citrusvariety.ucr.edu/citrus-varieties

UC IPM website https://ipm.ucanr.edu/PMG/menu.homegarden.html

Ants
https://ipm.ucanr.edu/PMG/PESTNOTES/pn7411.html

Selected Citrus Varieties for the Home Gardener https://anrcatalog.ucanr.edu/pdf/8472.pdf

Grafting and Budding Citrus and Avocados in the Home Garden
https://anrcatalog.ucanr.edu/pdf/8001.pdf

Forestierre Underground Gardens in Fresno, CA
https://undergroundgardens.com/

[From the UC Master Gardener Program Statewide Blog]

Proper irrigation and drainage are critically important for the health of plants and trees. But what happens when Mother Nature throws an atmospheric river curveball, and your yard or garden is now under water from heavy rains or floods?

Good garden soil contains a network of pore spaces filled with water and air. Both are necessary for healthy roots and beneficial soil-dwelling organisms. When the pore spaces fill with water, air is no longer available to the root system, and the roots become susceptible to root-rot organisms. Understanding the effects of flooding on plant health and caring for them after a flood event is important to saving your plants and garden.

Once the floodwaters have receded, assess the damage to your garden and begin the recovery process. There are a few things you can do to minimize the damage to your plants from flooding:

1. Remove any debris, such as mud and silt, that may have shifted and accumulated on your plants. 
   
   
2. If the soil is waterlogged, improve drainage by digging ditches or furrows to redirect water away from plants. 
   
   
3. Check the soil for compaction and loosen it up with a garden fork. This will help to improve drainage and make it easier for water and nutrients to reach the roots of your plants. 
   
   
4. Wait until the soil dries out before working with it in order to reduce additional compaction. Avoid walking on waterlogged soil to prevent compaction and further root damage. Stay off a boggy lawn!
   
   
5. Inspect your plants for damage to the roots, leaves, and stems. Remove any damaged parts, and prune your plants back to healthy growth if necessary.
   
   
6. Remove contaminated material. Consider that any garden produce touched by floodwater may be contaminated and discard it. While the risk of contamination is low in residential areas, runoff from septic systems, pastures, or industrial areas can carry potentially harmful microbes and chemicals.
   
   
7. Monitor your plants closely for signs of stress, such as wilting or discoloration, and address any issues that arise as soon as possible.
   
   
8. Once dry, start to water your plants gently and gradually to help them acclimate to the new soil conditions. 

Connect with us! 

Recovering from a flood can be a difficult and time-consuming process, but with proper care and attention, your garden can recover and thrive. The UC Master Gardener Program is available to help! For gardening questions and local county resources, click here to Find a Program. You will be redirected to your local county website and contact information. 

Source: Flood: Plant Stress in Extreme Wet Conditions, https://marinmg.ucanr.edu/PROBLEMS/EXTREME_CONDITIONS/Flood/

Signs of autumn are all around us. . .we've had some rain, trees are showing off their fall colors and losing their leaves, fewer plants are blooming, the days have gotten shorter with the nights getting chillier. While nature has its own way of coping with the colder winter months, there are plants in our gardens that can be sensitive to freezing temperatures. Citrus, succulents, perennials, young plants that recently went into the ground, and many tropical and subtropical plants can be vulnerable. But there are a few things you can do to help protect your garden during potential freezing spells.

Mulching Perennials

Perennials return year after year. Hardy ones will need little, if any, assistance to get through the cold months, but some may need protection. Mulching helps even the soil temperature, preventing the ground from freezing when the temperatures drop below 32°F/0°C. A layer of 2-3 inches is best. A deciduous plant's own dead leaves can help protect its crown and roots from the cold, so leave the leaves until next spring, adding more mulch as needed. Other sources of mulch include bark, straw, shredded branches, and compost.  

Trees and Shrubs

Trees and shrubs usually have an easier time getting through the winter if they are in good shape. However, if a freeze is forecasted, one of the most important things to do is to ensure they have been watered 2-3 days prior, especially if autumn has been dry. As with perennials, mulching with fallen leaves or other mulch will help protect the roots, but do not have mulch up against the tree trunk or plant stem, which could cause rot to occur.  

Wrapping trunks of young trees with blankets, towels or piping insulation will provide added protection.

Bulbs

Fall is the time to plant hardy spring-blooming bulbs, but some bulbs such as gladiolus, cannas and dahlias are sensitive to winter cold, and may not survive. You may wish to dig these up and store them over the winter.

Wait until after the first frost, then gently dig up the bulbs or tubers. Cut away any leaves and brush off as much soil as possible. Let them dry out in a cool spot for about a week. Label them so you'll remember what they are!  Pack them in a breathable box, such as a cardboard box, storing the bulbs so they don't touch each other, and cover them in sawdust or shredded newspapers. Keep them in a cool, dark location that is below 45°F, but doesn't freeze.

Citrus

Different types of citruses have different cold hardiness. The leaves, green wood and fruit are more frost sensitive than hard wood. Mandarins and kumquats are the most tolerant of cold, with oranges, lemons and limes being less tolerant. However, if a cold snap has colder than usual temperatures and/or lasts more than a short period, even mandarins and kumquats can suffer. Any ripe fruit should be removed prior to freezing temperatures.

Citrus plants can be protected by frost cloths which allow some light and air to penetrate and can stay on plants for a few days at a time. They can also lay directly on plant foliage. If you use other type of cloth such as burlap or cotton sheets, use stakes to hold the cloth away from the plant greenery. Remove it during daytime when temperatures are above freezing and sunny, and replace it each night prior to sunset. Whatever cloth you use, make sure the cloth goes all the way to the ground to capture radiant heat from the ground. If there is mulch around the plant, rake away during the day, if above freezing and sunny, to allow the soil to warm up. 

Roses

Some roses are more sensitive to cold than others. As a group, hybrid tea roses are the most vulnerable. Make sure they are watered prior to predicted freezing temperatures, protect the root zone with mulch on the soil mound. You may also wish to cover your sensitive roses with frost cloths.

Container Plants

As always, water the plant a few days prior to an expected freeze. Ideally, if you are able to pull plants in pots into the garage, shed, or other enclosed area, do so.  While not as effective as an enclosed area, moving container plants onto a patio, or up against the side of the house or garage, preferably beneath an overhang will provide some protection. If unable to move the container, you can cover them up with frost cloth as discussed in the citrus section.

What do do if frost damages your plants? Wait!

Frost damage occurs when the water inside the cells of a plant freeze, causing damage to the cellular walls, which harms the overall health of the plant. Frost damaged vegetation will wilt, turning brown or black, as if they have been scorched. The bark may crack, or split. In severe or prolonged periods of frost the plant can die.

If you see what appears to be frost damage, wait until late spring until all chance of frost has passed. Plants are resilient and can often recover on its own, producing new growth.  Pruning what seems to be damaged branches too soon can cause significantly more trauma, even death, to a vulnerable plant that might otherwise have recovered in the spring. 

Resources

• https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22929
• https://sacmg.ucanr.edu/Frost_Protection/
• https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=45517
• http://ipm.ucanr.edu/PMG/GARDEN/ENVIRON/frostdamage.html

Denise Godbout-Avant has been a UC Cooperative Extension Master Gardener in Stanislaus County since 2020.

If you spend much time outside, chances are you've sought the shade of a nearby tree. Whether walking your dog, visiting a shopping center, or having a picnic, a tree probably made your experience more pleasant. But how much thought have you given to the benefits of trees?

The Benefits of Trees

Trees provide so much more than shade. Here are a few reasons trees are important, courtesy of the International Society of Arboriculture (ISA):

• Air-conditioning costs are lower in tree-shaded homes & businesses; heating costs are reduced.
• In workplaces with trees, people report decreased workplace stress and fatigue.
• Cleaner air: leaves filter the air we breathe by removing dust and other particles.
• Cooler environment: trees reduce heat in and around parking lots and paved areas.

Trees and the Drought

California residents are being asked to lower their water use by 15%. One easy way to do this is to turn off your sprinklers. But wait! What happens to the trees? Although they may look okay for now, the stress of going without water will take a toll. Lawns can be easily replanted and replaced, but trees take many years to become established.

What do Trees Need?

Although sprinklers provide trees with some water, it's not delivered the best way. Trees need deep, slow, infrequent irrigation to stay healthy. As you can see in this photo, tree roots are just below the surface, in the top three feet. Watering underneath the drip line is best, but not too close to the base of the tree.

How Should I Water My Tree?

There is no “silver bullet” on how often or how much to water. This depends on many factors. Instead, after you water, take a shovel (away from tree roots) and check your soil. How deep did the water penetrate? Make sure water penetrates to a depth of 18” by digging with a shovel. Once that area is dry, water again.

Prioritize Watering Trees with the TRIC

One method you can use to ensure your trees receive sufficient water is the TRIC, or “Tree Ring Irrigation Contraption.” The TRIC is designed by researchers at UC Davis using drip irrigation hose placed strategically underneath the dripline of a tree, but not too close to the base. You can visit the California Center for Urban Horticulture for a free supply list and directions on how to create and set up the TRIC. A second method is to purchase a soaker hose and use it in the same way.

For more information about the value of trees, visit the following resources.

Resources

California Center for Urban Horticulture. UC Davis. Tree Ring Irrigation Contraption. https://ccuh.ucdavis.edu/tric

International Society of Arboriculture (ISA). Trees are Good. https://www.treesaregood.org/Portals/0/TreesAreGood_Benefits%20of%20Trees_0321_1.pdf

Water Talk. Janet Hartin. Podcast Episode 21. https://water-talk.squarespace.com/episodes/episode-21

This article was originally published on July 26, 2021.