- Author: Rho Yare
Yes, I realize that this past year has been, to put it mildly, a little out of the ordinary in many aspects. We have been for good reason a little pre-occupied with international, national, and of course local news. Besides concern for family, health, job security, and having enough toilet paper to “weather this current storm,” many in our population are witnessing the unbelievable: changes in spring training, changes in hockey games, changes in a favorite high school sport activity, and of course the massive changes in men's and women's NCAA basketball tournament. Which for many years has been monikered as “MARCH MADNESS.”
Seasons and the changes that appear have been celebrated for as long as our ancestors have wandered the earth. These people recognized that at certain times of the year the sun (our natural day/night clock) would appear at certain locations. Today most of us only know these important life and light changing dates because of our calendars or that perky news anchor announces that the season change is coming. Well, it occurred recently. We went from winter to spring. Did you see it?
Perhaps you might think about walking in your neighborhood. Many of us have been relegated to stay in one location, but still allowed to roam the streets using “social distancing.” Notice the yards with flowers that are blooming. The magnolia tree in my front garden bloomed a few weeks ago and the huge purple and white blossoms have dropped replaced by foliage. That is a miracle to me. I was pacing near my home (not a big fan of this stay place business) and saw irises, lilac, evergreen pear all in magnificent colors that only can be found in nature.
And if you have questions about plants in your neighborhood or seeds you wish plant the Master Gardeners of Stanislaus County are here to assist. We can be reached by phone or email and it is a free, non-judgmental service. Join us in celebrating the return of spring. Right now, we all need something to celebrate after our long, often difficult past year.
The UCCE Master Gardener's answer the Help Line Wednesdays from 9 a.m.-12 p.m. Other days and times, leave a message and we will return your call within two business days. (209) 525-6802. Or, fill out our survey to be contacted by email: http://ucanr.edu/ask/ucmgstanislaus
Note: these services are available for Stanislaus residents only. For other California counties, visit our map at http://mg.ucanr.edu/FindUs/ to find your local program.
- Author: Ed Perry
Most mature trees will not show any immediate effects of root cutting, such as wilted leaves or branch dieback, even when a fairly large number of roots are cut. Indeed, root cutting is a routine practice where landscapes are being renovated or sidewalks are being repaired. However, it's the long term effects of root cutting that needs consideration.
Roots can decay when they are attacked by microorganisms, usually fungi, that live in the soil. The microorganisms often infect a root through a wound, but some are able to penetrate a root directly, especially if the tree has been weakened by drought or overwatering. Some root rot fungi can kill a tree before it falls, others cause living and healthy looking trees to fall. You can sometimes see trees blown over with the remains of their decayed root systems still attached.
It is often very difficult to detect rotting roots, since the problem takes place out of sight below ground. Trees infected with root rot fungi sometimes have visible fruiting structures of the fungus, called conks or mushrooms, on the trunk near the ground. If you see such signs on a large tree, consider having the tree inspected by a qualified arborist.
Construction activities or trenching are especially damaging to the roots of nearby trees. Trenching and earth moving equipment used around trees often sever a large portion of the existing tree roots. Without the support of the entire root system, the tree is structurally weakened. The probability of failure increases as a greater amount of the root system is cut or damaged.
It is usually impossible to predict the exact effect that root cutting will have on a particular tree, or when an effect will occur. A tree may fail a few months or many years following root injury, or it may never fail due to the root injury. Tree species vary in their ability to tolerate root disturbances. Also, no two root systems are exactly alike. A tree with a deep, extensive root system will tolerate more disturbance than a neighboring tree with a poorly developed root system. In general, it is important to take every step possible to avoid cutting or damaging a tree's root system.
Despite an occasional failure, most large trees are very safe. Root systems are well designed by nature to hold trees up, regardless of the tree's size. For the most part, they do just that.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Elaine Lander
[From Pests in the Urban Landscape blog]
Mistletoe is a familiar sight of the season, often found wrapped in ribbon and hung for certain festivities this time of year. But did you know it is actually a parasitic plant that grows on a number of landscape trees in California?
There are two types of mistletoe in California. Broadleaf mistletoes attack certain broadleaf trees and some conifers, while dwarf mistletoes attacks only conifers. Broadleaf mistletoes have green stems with thick, oval leaves. Dwarf mistletoes are smaller, with short stems and yellow, scaly leaves.
Both types of mistletoe grow through tree bark and into the tree's tissue, living off the host tree. Healthy trees can typically tolerate a few mistletoe infections although individual branches may be weakened by the parasite. Trees with a heavy infestation can be stunted or even killed if they are stressed by drought or disease.
What can be done about unwelcome mistletoe? The most effective way to control mistletoe and prevent its spread is to prune out infected branches as soon as possible. If mistletoe is infecting a major branch or trunk, you can cut off the mistletoe and wrap the area to exclude light. See our Pest Notes: Mistletoe for additional instructions.
Reducing mistletoe is a community effort since it spreads easily from tree to tree. So if you find yourself underneath some mistletoe this season, be sure to share this information with your neighbor!
- Author: Denise Godbout-Avant
Why do some trees change color and drop their leaves before winter? And why are there different colors?
Leaves are colored by pigment molecules. Most leaves appear green because they contain an abundance of the pigment chlorophyll. Chlorophyll is the site of photosynthesis where the sun's energy is converted into the carbohydrates that are plants' food source. During the cold winter months when there is less sunlight, it would take too much energy for some trees to keep their leaves healthy. So deciduous trees lose their leaves for the winter. Evergreen trees have a different strategy for dealing with winter's challenges (which is a topic for another time!).
Elevation, latitude and weather all affect the timing and intensity of fall colors. Higher elevations and northern latitudes produce earlier autumn colors in trees. In general, autumn weather with lots of sunny days, dry weather, and cold, frostless nights will produce the most vibrant palette of fall colors. Some trees that can produce vivid colors include maples, gingkos, aspen, birches, Japanese maples, liquidamber, cherry, redbud, Chinese pistache, and dogwood.
In the Central Valley we usually don't get the glorious colors like the Sierra Mountains or the east coast, but we do get some color which usually starts in early November. So, enjoy the autumn jewels since it occurs only for a brief period each fall!
Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.
- Author: Ed Perry
Sunburn is damage to leaves and other plant parts caused by a combination of too much light and heat and insufficient moisture. The first symptom of this problem may be leaves that appear dull or wilted. A yellow or brown “burned” area develops on the leaves, which then dies beginning in areas between the veins.
The best way to avoid sunburn is to choose plants that are adapted to the planting site. Trying to grow shade-loving plants in full sun is asking for sunburn problems. But even sun-loving plants will suffer sunburning of leaves if the plants are growing in dry soil. You need to provide your plants adequate irrigation water to prevent most sunburning problems. If you notice the symptoms early enough, you may be able to restore the color to sunburned leaves before they killed.
Sunscald, also sometimes called sunburn, is damage to tree or shrub bark caused by hot sunshine. Sunscalded bark becomes cracked and sunken, and is susceptible to attack by wood-boring insects and wood-rotting fungi. In fact, I almost always find evidence of flatheaded borer injury in trees that have sunscalded bark. Sunscalded trunks and limbs can develop cankers, become girdled, and die.
Sunscald often occurs on young woody plants. Their bark is thin and may not tolerate exposure to direct sun because they were grown in nurseries where their trunks were shaded. Older trees can be damaged if you expose branches to the hot sun by pruning heavily, especially during the summer months. Removing taller trees that provided shade, or adding pavement or buildings that reflect light onto plants can also lead to sunscald. Even in well-watered soil, sunscald may injure bark if plant roots are unable to absorb enough moisture when it's hot.
You can prevent sunscald through proper planting and pruning. Prune newly planted landscape trees very little or not at all. Leaves not only shade the bark, but manufacture foods necessary for root growth. If there is no foliage growing along the trunk of a newly planted tree, paint the trunk with white interior latex paint, diluted 50 percent with water. Old bark that has been recently exposed to the sun by pruning or limb breakage can also be painted white. Wood chips and other organic mulches can reduce reflected heat and light, thereby reducing the danger of sunscald.
As always, it's important to plant species that are well adapted to the amount of light available in your garden. Also, avoid changing the environment in any way that significantly changes the amount of light your established plants are receiving.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
