By Brent McGhie, Butte County Master Gardener, November 13, 2015
Peach leaf curl is a fungal disease affecting only peaches and nectarines. Its distinctive symptoms include the curling, reddening, and thickening of leaves as they open in the spring. Diseased leaves will die and fall off, but are usually replaced by new, healthy leaves once the weather becomes warmer and drier. Still, if this disease is left untreated, defoliation can lead to sunburned limbs followed by borer attacks. Over several years, affected trees may decline and fruit production can be reduced.
To prevent peach leaf curl, trees must be sprayed with a fungicide after their leaves have dropped and they are dormant. This is usually in late November, or December. If it is a particularly wet winter, a second application of fungicide can be made in early spring, just as buds begin to swell. An easy way to remember is to target spraying for “curly leaf” at Thanksgiving and again at Dr. Martin Luther King's Birthday. Once peach leaf curl symptoms appear (when trees leaf out in the spring) it's too late for anything to be done to stop the disease. Spraying after symptoms show up is ineffective and removing diseased leaves or shoots will not remedy the problem.
For the home gardener, there are two treatment options. The most effective is the fungicide chlorothalonil (commercially sold as Daconil, Fung-onil, and Ortho Garden Disease Control, among other brands). However, it must be handled with care because it is listed as a likely carcinogen and can cause skin and eye irritation if handled improperly or if protective clothing and equipment (gloves and goggles) aren't worn. A somewhat less effective treatment is copper ammonium complex sold as Liqui-Cop (a Monterey Lawn and Garden product), or Kop R Spray Concentrate (a Lilly Miller brand). It can be made more effective by applying it with 1% horticultural spray oil in the spray solution. As is the case with all garden chemicals, be certain to read and follow all cautions and instructions on the label.
If you prefer not to spray, you can avoid leaf curl by planting resistant varieties of peaches and nectarines. Resistant peach varieties include Frost, Indian Free, Muir and Q-1-8. Although the Frost peach variety is very resistant to leaf curl, it must receive fungicide applications in its first two to three years of growth. Kreibich is a nectarine variety that is resistant to leaf curl.
Citrus blast and brown rot are diseases that attack citrus trees. Although citrus blast is caused by a bacterium that attacks leaves and shoots and brown rot is a fungal disease that causes fruit to rot and turn brown, both of these diseases can be controlled by spraying with the same copper ammonium complex used to treat peach leaf curl.
When heavy rain, high winds and low temperatures occur together, conditions are optimal for citrus blast, especially on the windward side of the tree. Leaves affected by this disease have a withered, bleached appearance, as if “blasted” by a blow torch. Diseased leaves and twigs will die and occasionally a larger branch can die back. In most cases, fruit production is reduced and the appearance of the tree is adversely affected.
As with peach leaf curl, once the symptoms of brown rot or citrus blast appear, it's too late to treat them. Both of these diseases are associated with cool, wet conditions, so the best time to spray is before the winter rains begin if you wish to protect navel oranges from brown rot, usually mid-October. A second spraying in mid-December and a third in mid-January has been shown to be effective in reducing the severity of citrus blast. For maximum protection, all parts of the tree should be thoroughly coated. The rough texture of mandarin skins can make it difficult to wash spray residue off of fruit. If this residue is not acceptable, an option is to delay spraying until immediately after fruit has been harvested.
By John Smith, Butte County Master Gardener, October 30, 2015
If gophers are a nuisance in your yard, 1/2-inch by1/2-inch hard wire mesh can be nailed to the bottom of a raised bed to prevent gophers from getting to plant roots while allowing water to drain through.
Frustration with gophers is the most common reason gardeners turn to raised beds, but there are many other advantages to this method of gardening. Raised beds allow you to garden no matter what your local soil may be: clay, sand, bedrock, or even contaminated soil. You get to choose the soil your plants will grow in. A mixture of 50% local soil and 50% compost often works well.
If working on your hands and knees is a problem, a raised bed can be built to a height that is comfortable for you. For example, an 18-inch high bed with a 6-inch perimeter board to sit on may be just the right height to facilitate the leisurely tending of one's crops.
The soil in raised beds tends to warm up earlier in the year than does the ground soil, allowing for a longer growing season. Raised beds can easily be customized to accommodate different crops in different seasons. For example, ¾-inch chicken wire, framed with PVC pipe and hinged to one side of the raised bed will prevent squirrels from entering and wreaking their havoc. Attaching clear plastic to the frame during the months of November through March creates a mini-greenhouse for raising salad greens throughout the winter. On sunny days in early spring, opening the enclosure about 6 inches will prevent overheating.
It's amazing how much food a three-foot by eight-foot raised bed can produce. Raised beds also tend to have fewer weeds and are easier to manage.
There are a few disadvantages to raised beds. The biggest drawback may be the expense of building the beds and filling them with soil. Keep in mind that they also lose moisture more quickly than does ground soil.
There are many options for raised bed designs and materials. Raised beds that are three to five-feet wide allow easy reach to the center for tending crops. If your access is only from one side, beds should be no wider than three feet. Redwood and cedar are the most common materials used, but there are many other possibilities. Galvanized steel or rubber containers used for watering cattle or horses can be used, so long as you put many holes in the bottom to allow for good water drainage. These containers are usually two feet deep. They should be available at your local feed store. Sometimes large culvert material can be found at metal junkyards. Particularly useful are those that are a least four feet in diameter. Even old, used, rusted galvanized metal roofing can be enclosed in a wood frame used for raised beds. These can be aesthetically pleasing and add a creative touch to the garden. Cement blocks can also be used to create raised beds.
Don't let gophers, squirrels, moles, poor soil, bedrock, or not wanting to work on your hands and knees deter you from the gratification of growing your own food or flowers! Consider a raised bed for your garden.
For more information visit The California Garden Web.
By Marsha Ebert, Butte County Master Gardener, and Joseph Connell, Farm Advisor Emeritus, October 16, 2015
The best solution is to avoid growing toxic plants where pets or toddlers will have frequent unsupervised access. If a toxic plant is eaten it's important to know what part of the plant (e.g. flowers, leaves, berries or bulbs) was eaten and how much of it was ingested. It's critical to know the name of the plant (both the common name and the scientific name) for a health professional to decide the appropriate course of action. When you purchase plants, keep the tags identifying the plant or keep track of the names on a written list so you can provide the needed information to your veterinarian or health care provider when necessary.
Plants on the California Poison Control System's toxic list have been rated according to their types of toxicity. Plants on the list that are toxic to humans are generally toxic to pets as well. Visit their website for a list of toxic plants and their ratings. As you can see from the toxic plant rating guide, some types of toxicity are much more serious than others.
Some of the plants on the list that are safe for humans can be toxic to pets. Common plants that stand out on the list as harmful to pets include:
Hermocallis spp. – Day lily, Basket lily
Cordyline spp. – Palm lily, Ti plant
Dracaena spp. (many species) – Lucky bamboo, Dracaena, etc.
Lilium spp. (many species) – Easter lily, Casa Blanca lily, Tiger lily, etc.
Schefflera arboricola – Dwarf schefflera
Vitus vinifera and V. californica – Grapes and wild grapes
WHAT TO DO FOR A PLANT POISONING
• Do NOT induce vomiting.
• Remove any plant parts from the mouth or hands.
• Wash around the mouth and hands and give a few sips of water.
• Check for any irritation of the skin, mouth or tongue.
• Call the California Poison Control System at 1-800-222-1222 (open 24 hours a day).
• Even if you are not sure, call the poison center for help. It will not be a waste of time.
• Do not wait for symptoms to appear. Treatment will be more difficult once symptoms have developed.
• If you are advised to go to the hospital, take the plant or part of the plant with you.
Poison center staff or veterinarians cannot reliably identify plants over the phone from a description of the plant. An unknown plant described as having shiny green leaves is not enough information to know what the plant is. Know your plants! If you don't know them, take the plant or samples of shoots with leaves, berries, or flowers with you when you seek medical care. Although not toxic, don't forget to check your pet for foxtails. The foxtail grass has a barbed seed head that can work its way into a pet's nose, eyes, mouth, or ears, and between their toes. Foxtail season usually runs from May through December. If a foxtail has become deeply embedded or the area around it is red and swollen, call your veterinarian.
By Cindy Weiner, Butte County Master Gardener, September 25, 2015
Water the plant every 3 to 4 days for the first month after planting. Let the ground dry out a bit between waterings. Dig down a few inches to check if the soil is still moist. If it is, wait another day or two and check again. After a month, switch to irrigating once a week and continue this schedule through the first spring and summer, discontinuing when the next rainy season begins. You can also mist the plants with water occasionally to wash dust from the leaves. During the second spring and summer, switch to a schedule of irrigating once every two weeks or once a month.
After the second summer, most natives will be fully established. Those natives that are fully drought tolerant will no longer need supplemental irrigation except during dry winters. Others will continue to need supplemental irrigation. You'll need to research the cultural requirements of your native plants in order to decide whether to continue irrigation. Consider where the plant grows naturally. If the plant is native to coastal fog belts, mountain forests or riparian zones, it will require extra water during summer and fall. If it's native to the Central Valley or Sierra or inland coastal range foothills, it's probably drought tolerant.
Getting your native garden off to a good start will help make your garden sustainable for the long term.
By Cindy Weiner, Butte County Master Gardener, September 11, 2015.
While it's certainly possible to start native perennials, shrubs and trees from seed, most people buy plants that are growing in pots to transplant to the yard.
Most natives are adapted to well-drained soils with little nitrogen. In fact, some natives cannot tolerate nitrogen-rich soils. Generally, no amendments are necessary except to improve drainage. If your soil is very heavy, choose natives that are adapted to clay soils or dig in some ordinary topsoil to form mounded areas that will drain better. Organic amendments like compost may be necessary if you are planting in a new development where the topsoil has been removed by grading.
Unfortunately, native plants are just as susceptible as non-native ornamentals to damage from pocket gophers. If you have gophers in your yard, consider planting in wire baskets that protect the roots until your plant is established.
Mulching the planted area will help retain moisture and suppress weeds. Add 2 to 3 inches of mulch, keeping it 6 inches away from the base of the plant. If you are using organic mulch (such as bark), it will need to be renewed periodically as it breaks down.
Paying careful attention to the planting process will give your native plants a good start.