Posts Tagged: Evergreen
The Colors of Spring.
By Corinne Yoshihara, UC Master Gardener of Napa County As I traveled through Napa Valley...
Fruit and Nut Trees for Coastal California
It's possible to grown many other tree crops along the coast other than avocado and citrus. When speaking of other perennial evergreens like avocado, trees that don't lose their leaves but retain a canopy year round, we want trees that can handle the occasional cold periods that happen in winter. In fact, some trees like 'Hass' avocado need something like 50 hours of chilling – hours below 45 degree Fahrenheit. When trying to grow ‘Hass' in the tropics, the tree gradually loses vigor because the cold need to break dormancy of buds isn't there. So they grow tropical varieties in Florida and the Dominican Republic and consumers get used to the less oily flavor of the tropical varieties. Low or no chilling requirement fruit trees like durian, jackfruit and other tropical fruit can't handle the cold we get in coastal California. There are many different unusual fruits that can be grown, like cherimoya, sapote and mango throughout the southland.
However, if we try to grow low chill varieties of deciduous fruit that can handle winter cold, like apple and peach varieties, they often have insipid in flavor. Here's a list of fruit trees that are adapted to coastal southern California. And if you choose any of the deciduous varieties, make sure you plant them bare root next winter. They are cheaper and transplant better with less transplant shock than planting them when they are in leaf.
http://ceventura.ucanr.edu/Com_Ag/Subtropical/Fruit_and_Nut_Varieties/
peaches
Wintertime Greenery
One of my favorite parts about the Christmas season is getting to bring a tree into my living room. I love the smell of an evergreen tree, and having one right next to my couch can't really be beat. I am certainly not alone in my love for greenery, and for bringing some of the outside inside. In fact, ancient cultures also used greenery to symbolize good luck and ward off evil-spirits during these darkest days of the year. I enjoy learning about the winter time traditions of other cultures and how they fit into how we celebrate Christmas today. A lot of these pre-Christmas traditions focused on a whole Christmas season, and on protecting the home from evil spirits that lurked during these darkest days of the year.
The Romans decorated with greenery for the New Year and also gave each other gifts known as strenae, sprigs and green branches gathered from the sacred groves of the woodland goddess of strength and endurance, Strenia. These evergreens were symbols of good luck for the year ahead. Sweet honeyed dates, figs, or small pieces of jewelry sometimes accompanied the strenae. Children were given small gifts, such as clay figurines or bags of nuts that could also be used as game tokens. To this day, gifts during the Christmas season are known as strenna in Italy and New Year's gifts are etrenne in France.
In preparation for the Twelve Days of Christmas (the twelve days following Christmas, December 26-January 6), prickly holly was placed around windows and doors - like evergreen barbed wire - to keep the roaming evil spirits, witches, goblins and trolls from entering the home and to protect the good fairies. Every sprig of evergreen had to be removed by the Twelfth Day or else bad luck would fall upon the home. The admonition to take down evergreens at the end of the Twelve Days was also applied to Christmas trees after they were incorporated into Christmas customs.
Mistletoe, the only exception to this rule, could be left up until the start of the next Twelve Days since it was thought to protect the home from lightening and fire. Mistletoe was held in awe because it remained green all year and bore its white berry fruit in winter when the trees on which it grew seemed lifeless. In the days of the Celtic Druids, this "magical" plant was gathered on special days in accordance with the cycles of the moon and was at its peak of power after the winter solstice (December 21).
Flowering Maple - Abutilon
Abutilon FLOWERING MAPLE Malvaceae EVERGREEN AND DECIDIOUS SHRUBS I was visiting...
When Winter Rains Don't Do Their Thing
"We don't need to irrigate, it's winter." This is a commonly held idea, and many years it is true. Adequately timed rains will often meet the needs of avocado trees during the winter period, and in times like last year, even satisfy much of the spring requirement. And the calls are coming in – “What’s wrong with my trees, they have all these brown leaves?”. This from San Diego to San Luis Obispo.
In a low rainfall year, irrigation can be as necessary as at other times of the year. This is because a subtropical evergreen like avocado continues to use water regardless of rainfall patterns. At the time of writing this article in March, we have had a scant 4 inches in Ventura and this is on top of a low rainfall year in 2011-12. Rain is necessary to leach the salts that have accumulated from the last irrigation season.
The driving forces for plant water use are light intensity, wind and relative humidity, as well as temperature. Remember how cold, dry winds can dry your skin or freeze-dry backpack food. Even during the winter, the trees are quite capable of losing large amounts of water with clear skies and cold winds.
Dry Santa Ana conditions are also more common in winter than in the past. This winter, a time of drought, I went out to see an orchard to evaluate it for pruning. On arrival, my first concern was for the water stress in the trees. The grower, however, was unconcerned. The trees had been dutifully irrigated the previous Friday. But over the weekend, a Santa Ana had blown for three days and completely dried the soil in the top 10 inches. Digging around the roots convinced the grower of water stress. Do not take irrigation for granted.
Contributing to the problem is the determination of what amount of rainfall is effective. Effective rainfall is defined as the amount of water that is retained in the root zone after rain. Avocados, especially on shallow soils, do not have much of a root zone. Most soils can be expected to hold about 2 inches of available water in the top 2 feet, less the more sandy, more the more heavy.
If rainfall exceeds the holding capacity within the root zone, it is lost to the plant. Just imagine if all the year's expected rain fell during one storm. It would not be long before irrigation would be required with no more rain coming. The extra water may, however, perform the all-necessary function of leaching accumulated salts from the root zone. When the rain gauge says that 2 inches fell, it is quite possible that all that rain will not be available to the tree. This also goes for the quarter inch storms we get that do not even make it through the leaf litter. It is not effective rainfall, even though it may wash the persea mite off the leaves.
One of the best ways to assess the effectiveness of rainfall within the root zone is with tensiometers. These trusty instruments are most commonly used to schedule irrigations. A good rainfall should return the 8- and 18-inch depth gauges to close to 0 cbars. This will tell you whether the rain thoroughly wetted the root zone. It will not tell you how much may have passed through the root zone, however.
If you are using soil sampling to assess the depth of rain infiltration, simply squeezing a handful of soil can help. Regardless of soil texture, a wetted soil will form a ball or cast when thoroughly wetted. Water moves as a front through the soil. After a rain, take soil samples with depth to find where the potential to form a ball abruptly ends. This will tell you the depth of effective rain.
How well a soil holds together can also be an indication of when to irrigate. Even a sandy loam texture will retain a ball that does not hold together well when there is still adequate moisture for the tree. The possibility of forming a ball decreases with water content. When visible cracking of a soil ball is obvious, it is time to irrigate.
Winter irrigation is something we do not commonly perform, but in low rainfall years it is an activity we need to consider, especially for controlling the salts that accumulate from our previous irrigation season.
Salt damage due to lack of leaching
avocado tip burn