Sunday, November 28, 2010

Post-Freeze Garden Tips

The average frost season for Sacramento is about two months, primarily December and January. But temperatures below 32 have been recorded as early as the first week in November; as late as the third week in March. This year, it was a Thanksgiving freeze, when temperatures plummeted into the low 20's Thursday morning, remaining there for more than 8 hours. Friday morning's lows also dipped into the 20's. And that's a recipe for definite plant damage.
 After several days of bone-chilling mornings with temperatures dipping into the low-to-mid twenties, should shivering gardeners:

a) remove all plants that look frost-bitten; 
 
b) prune away all freeze-damaged plant parts;

c) Purchase and plant again this weekend those same varieties of trees, shrubs, perennials and annuals;
                 


d) water the garden, even if the plants resemble toast;
            
e) fight the urge to prune and plant by staying indoors, next to the wood stove?

The answers happen to be the easiest to accomplish on a cold weekend: d) and e).

Even if plants in your garden look blackened and wilted now, new growth may emanate from the base of the plant when the weather warms up in a couple of months.

Pruning away the dead portions now exposes buds that may still be alive; another frosty morning could wipe out those survivors. 


Hostas will get new growth from the base.
Parsley can take a freeze. Tomatoes? No.

So, keep the shears in the garage and let the dead portions of the plants protect the understory. It may take until mid-Spring before you see new growth; patience is key before you pick up the pruners.

Make sure your garden and potted plants remain moist. Water
gives off heat, and this can protect plants from freezing, especially borderline citrus trees, such as lemons and limes. Damp soil retains heat better than dry soil, protecting roots and warming the air near the soil.

 


Other frosty garden tips that bear repeating:
• If you still have cold-susceptible potted plants on the porch or patio, move them to a sunny spot indoors or to a west or south-facing outdoor wall.

• Another way to achieve a few degrees of protection: construct a tent around a freeze-threatened plant, especially citrus, using frost blankets or row cover material. Your local nursery will have several products that will do this job. Old bed sheets work well, too.

• The larger sized Christmas lights or a couple of 150-watt light bulbs located in the central area of an orange tree (or any other cold-intolerant shrub) may add two to four degrees Fahrenheit of protection.

• Harvest any citrus fruit that is ripe, especially on the outer
branches.

• Wrap any exposed plastic water pipes; cover outdoor faucets, as well.

• Adjust your pool, spa or pond filtration timers so that they are running when the chance of freezing temperatures is greatest, between 2 and 9 a.m. Moving water is less susceptible to freezing.

• Make sure the backyard birdbath isn't frozen over in the morning.

• Daily fresh water for dogs and cats is also a good morning habit.

And what about those plants that have frozen past the point of
return? Should you replace them with the same varieties? That frozen ficus may be Mother Nature's way of telling you: "Hey! This ain't San Diego! Pick outdoor plants that can take colder temperatures!"

 

Coleus, a summer annual here: It's dead, Jim.

From the garden e-mail bag, Rob asks: "A lot of my lantana was burned by the cold weather. Should I trim in winter or wait until spring?"
Lantana is from the tropics, so it is a borderline plant here.
A light frost usually just damages the outer leaves; but a heavy frost or freeze may kill the entire plant. The good news: it may come back to life with new growth from the base, but not until late in spring. In the meantime, do nothing. Those dead branches may be keeping the base alive.

Tuesday, November 23, 2010

Walnut Trees At Risk in November Freeze

As if protecting your citrus trees and tender perennials from an impending November freeze isn't enough to fill your day. Walnut trees, too, are at risk when the temperatures plummet to the 20's in November.

True, the walnut harvest is mostly done by now. But the walnut tree itself could be injured or killed by a November freeze if the tree hasn't entered dormancy.

Check your walnut trees. If you see emerging leaves at the shoot tips this time of year, your walnut tree is not in dormancy. 

A prolonged, late autumn freeze following a period of relatively mild weather (remember the 70's last week, including a high in the 80's on Nov. 16) sets the table for walnut tree damage to vigorously growing, non-dormant young trees. 

Trees that have been hardened off are less susceptible to damage in an autumn frost.  But in the winter, even dormant, mature walnut trees can be injured by extreme cold.

According to UC Farm Advisor Carolyn DeBuse, both types of cold damage (autumn and winter) show similar symptoms of darkening bark and streaks of gray on the inner wood. In the spring, buds are slow to break or fail to break altogether. In cases where the branch dies, the winter kill acts as a severe pruning and vigorous shoots grow from below the damaged area. Sunburn often accompanies the cold damage increasing the amount of injury. In the harshest instances, entire young trees can die.

The good news: this usually happens only to walnut trees that are drought-stressed or are in dry, sandy soil. The copious rainfall we have had this autumn may lessen the chances of frost damage.

DeBuse points out that a good precautionary measure to take after a frost or freeze is to paint the trunks of the walnut trees. This is effective in reducing damage to young trees after a November frost. Paint the tree trunks and primary scaffolds above the crotch with a whitewash made of white interior latex paint diluted with 50% water. The paint will help prevent sunburn and help heal the damaged wood by reducing evaporation from the injury. In a study by Wilbur Reil, Yolo/Solano Farm Advisor Emeritus, 46% of unpainted trees sustained cold damage while only 8% of the trees painted 8 days after the event showed damage.

And just as we've recommended before with other plants that get frozen back, Dubose says not to prune out damaged walnut limbs in the spring. The buds may be slow to open. Don't prune out any suspected dead wood until the late summer. And she suggests to reduce or delay any applications of fertilizer to your walnut trees in the spring where cold damage has been spotted.

Read about more steps DuBose suggests for reducing freeze damage to walnut trees here.

Sunday, November 21, 2010

Thanksgiving Freeze Predicted. Is Your Yard Ready?

  Last week, we talked about strategies to protect your citrus trees from any expected mild frosts, when morning temperatures dip just below 32 degrees for an hour or two. 

     But what if the often predicted fall/winter freeze, when temperatures fall into the 20's for several hours each morning, settles into the area? The National Weather Service is forecasting overnight lows to dip below freezing, with many places just outside Sacramento falling into the 20's Tuesday, Wednesday and Thursday (Thanksgiving) this week. What else needs to be done in the yard to prep for a prolonged freeze when temperatures are forecast to fall to the upper 20's for several hours?
    

     Many of us learned this drill back in 1990, when consecutive low morning temperatures of 22, 18, 21 and 23 in Sacramento descended upon us during the period of December 21-24. Temperatures did not get above 25 degrees in parts of the San Joaquin Valley for three to five days and all time record low temperatures were set at Sacramento, Stockton, and Bakersfield. Many records were set for duration of freezing temperatures. The agricultural industry was devastated as acres of trees, not just fruit, were destroyed. Thirty-three counties were disaster-declared.

     Homeowners learned which plants don't like it cold (hibiscus, geraniums and other plants popular in the Bay Area and Southern California); and, which plants were the hardy survivors (another reason the oleander was chosen for the Highway 99 median strip). 

     Here's a last minute checklist for your home and garden if the TV weather people tell you tomorrow's low will be in the 20's:
 
• If it hasn't rained, water plants thoroughly, especially container plants.

 
• If possible, move sensitive container plants next to a south or west facing wall.

 
• Cover citrus and other sensitive plants with burlap, row cover fabric or sheets (be sure to keep the sheets dry). Tent plastic sheets over the plants; don't let plastic touch plant leaves. A light bulb placed in such a plant can offer a few degrees of protection.

 
• If using an anti-transpirant polymer coating material such as Wilt-Pruf or Cloud Cover, apply at the warmest time of the day, or at least six hours before an expected frost. However, research conducted at Washington State University concluded that these products may actually be detrimental to certain plants during a freeze. If using these products, thoroughly water the soil around the plant before applying.

 
• Disconnect hoses and drip lines, removing end caps. Lay out straight.

 
• To prevent broken grass blades, don't walk on a frozen lawn.

 
• Remove the lowest sprinkler head to drain.

 
• Cover unprotected faucets and pipes, including any spa or pool equipment.

 
• If temperatures are predicted to fall to the low 20's: prevent frozen attic pipes. Let lukewarm water trickle out of the indoor faucet farthest from the inlet. Also, let faucets with pipes running along an outer, north facing wall trickle during the night. 


• Ideally, add insulation to attic water pipes.
 
• Open cabinet doors to get more heat to the pipes. Close the garage door if water pipes pass through the garage.

 
• Setting your thermostat nightly at 55 can add needed heat to the attic pipes.

 
• If leaving the house for a Thanksgiving vacation during an expected freeze, turn off the water to the house, and open up the faucet farthest from the inlet. Be sure to turn off your water heater.

 
• To prevent cracking tile, run your pool and spa equipment during the freezing hours.


• Don't forget about your pets during a prolonged freeze. Bring them indoors at night. Move or replace their drinking water. Break up any frozen water in bird baths.
    

    
Their is some good news connected with a possible freeze: populations of yellowjackets, eucalyptus-feeding red gum lerp psyllids and grasshoppers could be greatly reduced in 2011.

Thursday, November 18, 2010

Citrus Protection in a Frost or Freeze


We are now officially entering the shivering season for the Central Valley, Bay Area and low foothills. Late November through mid-February is the most critical time for protecting frost-susceptible plants.





This is especially true for citrus tree owners, who are anxiously keeping an eye out on the upcoming weather forecasts.

For instance, the current seven day forecast for Sacramento calls for overnight temperatures to drop into the low 30's, Sunday through Tuesday. But depending where you live, it could be lower; all gardening is local.

Several days before an expected frost (temperatures dipping down to 32 degrees) is the time to gather the necessary implements to protect your citrus trees, including giving the ground beneath them a good soaking (moist soil is better than dry soil at moderating the temperature beneath the tree).

Most gardeners first thoughts about protecting their citrus trees during a frost or freeze is, "protect the fruit!"

Four Winds Growers, the Winters-based wholesale grower of many excellent varieties of citrus, offers the Citrus Variety Information Chart at their website, FourWindsGrowers.com

Included in that chart is extensive information about each citrus variety, including suitability for indoor growing; its bloom and fruiting seasons; its recommended summer heat level to produce good fruit; and, its minimum tolerable temperature for preservation of fruit quality.

  The chart points out that lemons, limes and citrons are most sensitive to frost, while sweet oranges, grapefruit, tangerines and calamondins are intermediate. Kumquats and Owari Satsuma Mandarins are the most frost-tolerant, braving temperatures into the twenties (that would classify as a freeze).

From that chart, here are the temperatures (in degrees Fahrenheit) at which citrus fruit damage may occur.

Sweet Oranges
Washington Navel Orange  28  
Trovita Orange  28  
Cara Cara (Pink) Navel Orange 28  
Lane Late Navel Orange  28  
Robertson Navel Orange  28  
Shamouti Orange (Jaffa Palestine)  28  
Valencia Orange  28  
Midknight Valencia Orange  28  
 
Blood Oranges
Moro Blood Orange  28   
Sanquinelli Blood Orange  28   
Tarocco Blood Orange  28   
 
Sour Oranges
Bouquet De Fleurs Sour Orange  28   
Chinotto Sour Orange (Myrtle-Leaf)  28  
Seville Sour Orange  28  
Bergamot Sour Orange  32  
 
Mandarins
Gold Nugget Mandarin (Patented)  26  
Tango Mandarin (Patented)  32 
Owari Satsuma Mandarin  24  
Dancy Tangerine  32  
Clementine Mandarin (Algerian)  28  
Murcott Mandarin  32  
California Honey Mandarin  32  
W. Murcott Mandarin  32  
Kinnow Mandarin  32  
Kara Mandarin  32  
Page Mandarin  32  
Piie Mandarin  32  
Kishu Mandarin  32  
 
Lemons
Improved Meyer Lemon  32  
Eureka Lemon  32  
Lisbon Lemon  32  
Ponderosa Lemon  32  
Variegated Pink Lemon  32  
Yen Ben Lemon  32  

 
Mediterranean Lemons
Villafranca Lemon  32  
Genoa Lemon (Gea)  32  
Limonero Fino Lemon  32  
 
Limettas
Millsweet Acidless Limetta  32  
Marrakech Limetta  32  
 
Limes
Bearss Seedless Lime (TahitiPersian)  30  
Kaffir Lime (KiefferThaiWild)  32  
Meican Lime (Key)  32  
Thornless Meican Lime  32  
Meican Sweet Lime  30  
Palestine Sweet Lime  30  
Rangpur Lime  32  
 
Grapefruits
Oroblanco Grapefruit  32  
Rio Red Grapefruit  28  
Star Ruby Grapefruit  28  
Chandler Pummelo  28  
Cocktail Grapefruit  28  
Chinese Grapefruit  28  
Melogold Grapefruit  28  
 
Kumquats
Meiwa Kumquat  28  
Nagami Kumquat  24  
Indio Mandarinquat  26  
Centennial Variegated Kumquat  30  
Nordmann Seedless Nagami Kumquat  28  
Marumi Kumquat  26  
Eustis Limequat  32  
 
Citrons
Buddha's Hand  Fingered Citron  32  
Etrog Citron (Ethrog)  32  
 
Other Interesting Varieties
Minneola Tangelo  28   
Australian Finger Lime  32   
Yuzu  24   
Calamondin  32 
Variegated Calamondin  32


But what about the overall health of the citrus tree? How low can temperatures go during a freeze event before the tree is toast?

 "I consider 22 degrees to be terminal for citrus tree cambium cells," says Cedar Seeger of Four Winds Growers. The cambium layer is the growing part of the tree, the cells that are producing new wood and healing wounds. It is located just beneath the bark.

And that's for a citrus tree in tip-top shape: good health, with moist soil around it during a freeze. Cedar uses the example of a Meyer lemon tree:

"
We often have a two to three hour dip to 28 degrees after storms; and if the above conditions are met, even Meyer lemon trees can survive, albeit not to happily, without protection. 28 degrees for four hours probably won't kill the tree, provided the rootstock cambium doesn't freeze. It will defoliate and lose twigs. At 24 degrees things start to get dicey.
  
Ideally, this frost blanket should be touching the ground.


That's when the frost blanket, bonnet and lights will work wonders. Remember, those blankets and bonnets need to go to the ground in all cases."







When a large, cold-air mass moves in from the north after a storm in the winter, that is called an advective freeze. The one that sticks out in most gardeners' memories here was the freeze of mid-December 1990, when nighttime temperatures fell into the teens for several days in a row, with a couple of days that didn't climb above 32 degrees. To add even more injury, a second cold snap hit near the end of the month, with temperatures dipping into the mid-20's. Many of the most susceptible (frost intolerant) landscapes were completely lost; some nurseries never recovered.

"Our first year in the citrus business here in Winters was 1990-91. My wife, Mary Helen, and I have a Masters in Disaster," says Seeger. 

Which is why Cedar is an adherent of watching the dew point, the temperature at which saturation has been reached, when water vapor condenses into water. The lower the dew point, the more danger of cold damage to your plants. One good online source for dew point temperatures is the National Weather Service's Tabular Forecast Page  , which offers a forecast for two days in advance (that link is for Sacramento).

"A good watering going into an advection night is mandatory. If the ground and surrounding grass is wet, it creates a micro dew point environment around the trees. In a dry, cold La Nina winter such as we're about to get, it is important to remember the dew point concept. At 22 and below, it's full on emergency response, pile straw, hay around trunks, anything, lights, covering," says Cedar, a man who learned these lessons the hard way.  But he is not an adherent of running sprinklers during a freeze.


"My experience with overhead sprinklers is that they more often than not freeze up, and then it's all over. And you are risking branch breakage on that ice-entombed citrus. Yeah, it can work, but screw it; it's messy, risky and a lot of work. Use the large Christmas lights and mid-weight frost covers. But pay attention to the trunk / rootstock. If that freezes, it's a goner."


Citrus trees most at risk to fatal damage from a frost or freeze are the young trees. It is vital that they be covered completely when a heavy frost or freeze is predicted, and provide protection for the trunk, bud union and rootstock area. That can include trunk wraps, newspapers, old carpeting. 

In his book, "Citrus" , author and grower Lance Walheim also suggests applying a copper-based fungicide to the trunk and then mounding or banking soil against the trunk and lower limbs. Just don't leave it on too long; fungal rots can develop (that copper can only work for a limited time). He advises leaving that soil next to the trunk from Thanksgiving until February, or March, in colder areas.


And Thanksgiving, by the way, is next Thursday.

Wednesday, November 17, 2010

Bring Out the Homegrown Mixed Nuts

Thanksgiving is next Thursday, an occasion certain to bring the nuts out. 

And we're not talking about your wacky cousins from Merced, the ones who attempt to balance spoons on their noses during dessert.

Or eat dog food on a dare. 

A more common assortment of nuts found at family gatherings this time of year is that ubiquitous bowl of mixed nuts, usually located far from the kitchen, a better way to keep those other nuts out of the busiest room of the house, looking for spoons. 
From top right: pistachios, pecans, filberts, almonds, chestnuts, walnuts


And no doubt the question has been raised during football timeouts in the TV room, as four hands reach simultaneously for the last of the pecans: considering the astronomical price of mixed nuts, why not grow your own?

    Patient gardeners with some space can start their own "mixed nut" garden in the weeks ahead. Nut trees in bare root form will be available at nurseries from late December through February. 


Here are the nut trees that do well in our area (with links to more information about each variety):

* Walnuts. This important agricultural commodity here can thrive in your yard, if you have room for a couple of trees that can get 50 feet tall with a spread of 60 feet. Varieties for the Valley include the "Hartley" and "Chandler". For smaller yards, choose "Pedro", which is about two-thirds the size of other walnut trees.


* Almonds. Good choices for smaller yards include the "All-In-One" and "Garden Prince", which grow less than 15 feet tall and do not need another tree nearby for pollenization. Bigger almond trees for our area include "Mission", "Butte" and "Nonpareil", all of which need a pollenizer.


* Chestnuts. Large trees (40-60 feet tall) that prefer acid to neutral soil pH (5.5-7.0) and don't like soils that are too wet or drain poorly. For best pollination, plant one of each variety: Colossal and Nevada.

* Filberts (aka Hazelnuts). More than one variety is necessary for pollination in order to get a good-sized crop of filberts. Try interplanting "Barcelona", "Butler", "Casina" and "Ennis". And good luck; we've attempted to grow filberts at our place for more than 15 years. Total nut harvest in that time: 8 filberts.


* Pecans. Another tree that needs a lot of space, with a spread of 50-70 feet. Another iffy choice for Northern California; pecans do best south of Fresno. Good choices for home planting include "Mohawk" (a self-fruitful variety) and "Pawnee". The tandem of "Western Schley" and "Choctaw" work well for pollination.


 * Peanuts. Not a tree, but an annual crop that grows in the summer in sandy, well-drained soils. Try the "Jumbo Virginia", "Spanish" and "Valencia Tennessee Red" varieties. Peanuts ripen underground, by the way.


    Two commonly found mixed nuts that are best left to gardeners closer to the Equator: cashews and Brazil nuts.


Instead, add a couple of pistachio trees to your mixed nut garden. A male and female pistachio tree are needed, such as the combination of "Kerman" and "Peters".

Sunday, November 14, 2010

Cat-Proofing Your Garden

Ha! You can't.
Just as rainwater will always find a way to get inside your house, cats will find a route into your garden. Cats like jungles. Your garden is a jungle. 
Therefore, Cats ♥ Your Garden.


Cat in Garden (Cat Lover View)
Cat in Garden (Gardener's View)


                                                     
Besides digging up and making a mess around new, small plants, cat feces is not something you want in your vegetable garden, especially.


"Dog and cat droppings often contain roundworms and other parasitic nematodes. Gardeners can ingest roundworm eggs from soil contaminated with dog or cat feces. Contaminated soil often is carried to the mouth by dirty hands, especially among young children, or the edible parts of fruits and vegetables. Infection by just a few roundworms usually causes no problems, but more severe infections may cause fevers, bronchitis, asthma, or vision problems.

Another concern with cat feces is toxoplasmosis, a parasite that infects humans and other animals. Of all creatures, only cats are known to excrete oocysts--a form of the parasite that can survive in the environment for years and is resistant to most disinfectants.

Toxoplasmosis is a serious concern for pregnant women, persons with AIDS, and patients receiving immunosuppressive treatments. Most others who contract toxoplasmosis exhibit mild symptoms, such as headaches, muscle aches, swollen lymph nodes, or sore throats. Humans become infected with toxoplasmosis primarily by injesting contaminated food and water."

 Among the remedies recommended over the years to keep cats out of the garden:

Dogs.  
Pros: Barking is an initial deterrent. 
Cons: Dogs and cats eventually form a chilly alliance. Plus, have you ever seen cats gang up on a dog? I have. Guess who controls the garden after that skirmish?

Adding distasteful or foul smelling products to the perimeter of the garden
Items such as cayenne pepper, fox or coyote urine. 
Pros: Will keep cats out. 
Cons: Works only for a few days; or, if it rains. Pepper is also an irritant that could harm the eyes of cats. They get it on their paws, then wipe their paws over their eyes. Also harmful to toddlers and dogs. Not recommended.

Some suggest ringing the garden with lots of citrus peels. That keeps cats away...but attracts possums, skunks and raccoons. 

What about mothballs? 
No. Although some websites tout this as a cat deterrent, you are risking the health of your own pets and children, as well as the cats. Mothballs are highly poisonous, says the ASPCA. Naphthalene, a chemical found in some brands of mothballs, is toxic to dogs, cats and other animals, and if ingested, can cause serious illness and even death. Another active ingredient found in mothballs, para-dichlorobenzene, can cause stomach upset and worse.


Other bad ideas: plastic forks, handles buried, with the tines facing upwards; sharp pointed pine cones or thorny rose bush branches scattered throughout the garden. 
Pros: Cat will learn quickly to avoid the area. 
Cons: Causes possible animal injury. Moreover, humans do not learn as quickly as cats. Gardening becomes a painful exercise. Think: Homer Simpson.

Noisemakers with a motion sensor.  
Pros: Discourages cats until they get used to the noise. 
Cons: Do you want to wake up four or five times a night to the sound of recorded gunfire or cymbals? How about your neighbors?

Impulse sprinklers equipped with a motion sensor. 
Pros: The noise and water initially deters cats. 
Cons: Water comes on frequently at night, possibly leading to fungal problems on the plants.

Laying chicken wire over the surface of the garden before planting. 
Pros: keeps cats from scratching holes into the soil. 
Cons: forget about trying to work the soil or adding granular fertilizer afterwards. Also, the chicken wire tends to "disappear" below the soil surface, a hidden trap for a rototiller or spading fork. Pulling out large weeds may also bring up the chicken wire.


In our country acreage, which we share with six feral cats (all of whom have been trapped, fixed and returned), I have found this to be an effective cat deterrent in our raised vegetable garden beds:


 
Six inch mesh concrete reinforcement wire, suspended about an inch or two above the garden surface. Cats are not fond of tiptoeing through the mesh openings, and are reluctant to "do their doodie" in such tight quarters. 
And if they do (rare, but it happens), it's left on the surface and easily picked up with a trowel and discarded. 

This type of wire is usually sold in 4'x5' sheets at home improvement centers. A good pair of wire cutters can custom fit these 12 gauge sheets to the garden bed. They are easily removed for tilling in compost or repairing the drip irrigation lines. And the six inch grid makes a great template for seed or plant spacing.

Think of cats and Bermudagrass as your backyard twins: neither can be eradicated from your garden... just controlled.

Friday, November 12, 2010

Some Sharp Opinions About Pruning Tools

Dramm Pruning Tools
This time of year, stroll down the tool aisle of any garden center and you'll find a vast array of cutting instruments, all designed with the backyard gardener in mind. Blade heads of short-handled pruners and long-handled loppers usually come in two different styles: bypass and anvil. 





Felco #2 Bypass Pruners
Bypass loppers or pruners have a stainless steel curved blade that uses a scissors action to pass next to, not on top of, the lower surface, sometimes called the hook, designed to catch and hold the branch while the cutting blade comes down. 
    

Corona Bypass Pruners
         


Bypass pruners offer a cleaner cut, as the blade slices all the way through the stem. 








The cutting blade of anvil-style pruners comes down onto the center of a soft metal or hard plastic lower surface, called the anvil or table. Anvil pruners tend to crush the soft tissue of the stem, stopping the flow of nutrients, prolonging the healing time for the cut surface.

         Despite the bypass pruner's benefits, garden centers still offer a nearly equal number of anvil-style pruners and loppers, a never-ending source of confusion for the gardener hunting for cutting tools. 

So, we asked area garden experts their pruning preference: bypass or anvil?

         Sacramento County Farm Advisor Chuck Ingels prefers bypass pruners. "I never use anvil pruners because you often can't cut close enough to the branch collar without leaving somewhat of a stub," says Ingels. "When they begin to wear, they often don't cut all the way through. Also, they crush the bark, which bypass pruners can do also, but you can turn the shears so the blade is closer to the collar and make a clean cut."

         "I don't use and usually do not recommend anvil pruners," says Luanne Leineke, Community Shade Coordinator for the Sacramento Tree Foundation. "I tend to see too many wounded branches, particularly when the bark is soft. I suggest using bypass pruners for up to three quarters of an inch-thick branches, loppers for up to one inch thickness and a hand saw for anything larger."

         Pete Strasser, former plant pathologist with Sacramento's Capital Nursery, has only one use for anvil pruners. "Anvils are for deadheading annuals, and that's about it."

         Loren Oki, Landscape Horticulture Specialist with UC Cooperative Extension in Davis, also has limited use for anvils: "I was taught that bypass pruners were used on live material, whereas the anvil types were better for dead wood. The bypass type cuts cleaner through the softer material without causing much damage."

         Steve Zien, owner of the Citrus Heights-based organic landscape consulting business, Living Resources, leaves no doubt to his preference: "I would never use anvil pruners! Never ever, unless something needed to be pruned right then and there, and it was the only tool I had beside my teeth."

 

Tuesday, November 9, 2010

Dodder: The Return of the Zombie Spaghetti

Four years ago, we beat back an invasion of zombie spaghetti; but this crawling menace has returned. Back in 2006, a leafless, stringy, yellow parasitic vine, Japanese dodder, was discovered on host plants and trees in several Sacramento County neighborhoods.  At the time, this invader was stopped; at least that was the hope.




The latest find was this month near Clarksburg, in Yolo County, adjacent to the Sacramento River. One official surmised that dodder seeds or plant parts were spread there deliberately, in order to harvest the mature plant for medicinal purposes. Currently, the Yolo County Agriculture office is working with the California Department of Food and Agriculture (CDFA) to come up with an eradication plan.

Japanese dodder, also called strangleweed, resembles contorted spaghetti and is a non-native aggressive species that is spread by seeds, stems and roots, and can quickly move to other host plants. Once a seed or growing tip finds a host, it sends root-like structures called haustoria into the host's limbs, sucking out water and nutrients. Severe infestations can kill host plants. Japanese dodder attacks full-grown trees including many of our California native and agricultural fruit trees. And it is one tough seed. Dodder seed can survive soil solarization, a method for killing weeds using a clear, plastic tarp and the sun’s heat. Why? Probably because of its hard seed coat.

Japanese dodder, Cuscuta japonica,  is native to Asia. It will also attack and cover just about any garden plant, especially ornamental shrubs and fruit trees, with a preference toward citrus. However, Japanese dodder also can parasitize annuals, perennials, and trees such as oaks and willows. 

Contact your county agricultural commissioner to receive proper identification and help with control.

So far, control of Japanese dodder is through mechanical removal of the host, but because stem fragments act as propagules, only agency officials should remove Japanese dodder at the time. This will ensure correct vegetation disposal and prevent spread.  

 At the CDFA website, you will find this Japanese dodder FAQ:

Japanese Dodder
What does Japanese dodder look like?

Vibrant yellow-green to gold leafless vine.
Robust, round, twining stems that are fleshy and/or stout (1 – 3 mm in diameter), possibly with small red to purplish spots. 




Mature stems are comparable in size to cooked spaghetti.
Unlikely to have flowers (normal flowering season is August – October).
If flowers are found, they will be small (3-7 mm), sessile, pale yellow to cream colored, in short, dense axillary spikes.
 
Infestations often large, spreading, and web-like. Frequently covers large shrubs and small trees.

Where is it likely to be found?


Currently, infestations have been found in the counties of Alameda (Oakland), Butte (Oroville), Contra Costa (El Cerrito, San Pablo, Pinole and Richmond), Fresno (Fresno), Merced (Merced & Winton), Shasta (Redding), Sutter (Yuba City), Tulare (Visalia), Yolo (West Sacramento), Yuba (Olivehurst and Marysville), Sacramento (Sacramento), and Los Angeles (Los Angeles).

Infestations are highly correlated with Asian immigrant residential neighborhoods.

Possibly near roads and freeways.

Probable hosts include fruit trees and ornamental shrubs, although it can occur in native plants such as willows and oaks.

Japanes dodder wrapped around fennel

How is it different from native dodder species?
Japanese dodder is vibrant yellow-green or gold. 








Native dodders are typically orange.
Japanese dodder has thick, robust stems.

Native dodder (CDFA photos)

Native dodder stems are usually more thread or string-like.
 








Japanese dodder infestations are typically large, entirely covering shrubs or trees.

Native dodder infestations are likely to be smaller, infecting nonwoody plants or small shrubs.

Japanese dodder has been found in residential areas and ornamental plantings. 

Native dodders are found in wildland areas or crops.

Japanese dodder is unlikely to be found in hot, dry desert climates or at high altitudes.

If you find an infestation:

Do not attempt to remove or control it with herbicides.

Document the Location with GPS coordinates.

If GPS is unavailable, write down the address and/or nearest cross streets and/or directions to the site. Be specific!

Identify the host plant(s), if possible.

Take pictures.

Call or contact your County Ag Commissioner's office or the CDFA. They may ask you to collect a sample.

In Yolo County, contact the Ag office via their website or telephone 530-666-8140. 

More information on dodder is available on the California Department of Food and Agriculture website.

In Sacramento County, Suspected Japanese dodder sightings may be reported to the Sacramento County Agricultural Commissioner's Pest Hotline at (916) 875-6744 (recording 24 hours a day),

Monday, November 8, 2010

Pretty Pokeweed: Fall Color That Will Knock You on Your Butt

"Fall Color" isn't just limited to the changing hues of the leaves of deciduous trees this time of year. There are lots of colorful shrubs right now, producing flowers and berries, many of which are outstanding garden plants: cotoneaster, toyon, bottlebrush, the strawberry tree, Oregon grape, pyracantha and beautyberry, for example. But there are some pretty poisonous plants putting on a show right now in Northern California. Plants, that if you get a little too curious, could knock you on your ass.

For example, Laura writes in, with pictures:



















 

This gorgeous invasive plant invading her Citrus Heights backyard? Pokeweed.

 After posting these pictures at the Get Growing with Farmer Fred Facebook Page, valley and foothill gardeners responded with words of warning:

"It is poisonous and it is becoming an invasive weed in California and so is posted as a noxious weed. I had a friend who had them in their yard and their son wrongfully thought they were elderberries so they had picked a bunch to make jam. Thankfully she didn't get time to make that jam and they got moldy."

"Definitely pokeweed...would not recommend putting in the compost pile...they also have a deep tap root and are hard to get rid of...Placer County posted a warning on this plant as being both poisonous and invasive."

Cindy Fake of the Placer County Cooperative Extension office has written extensively about the dangers of pokeweed (Phytolacca americana, also known as pokeberry, inkberry and American pokeweed):

"If you have seen this plant, beware!  Pokeweed, a poisonous invasive species, has become more and more common...pokeweed is a rapidly growing perennial shrub, up to 10 feet tall, with large leaves and red stems. While some homeowners may be tempted to keep pokeweed in their gardens because of the pretty white flowers and glossy dark purple berries, all parts of the plant are toxic to humans, pets, and other mammals.  Pokeweed berries provide food for birds, which are not affected by the toxins. However, the birds then spread the seeds, helping the plant to invade orchards, fields and yards, and competing with crops and ornamentals. Once established, pokeweed can be very difficult to eradicate.  It grows a very large taproot, and can have multiple stalks growing from a single root. Do not put plants or berries in green waste disposal bins or in compost. Unfortunately, the taproot usually remains and often resprouts the following year." 

More pokeweed facts here.

Those of you from the South may recall "poke salad" as more than a song by Tony Joe White. As Cindy Fake points out: "in some parts of the US, young pokeweed leaves are eaten after extensive processing to remove toxins, but even after processing, some toxins remain, so consumption is not recommended."
          
Agreeing with that is the California Poison Control System, which reports pokeweed (Inkberry) as a Class 3 toxin: "Ingestion of these plants is expected to cause nausea, vomiting, diarrhea and other symptoms that may cause illness but is not life-threatening."


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

Friday, November 5, 2010

Frosty News for the Worried Gardener

For the longest time (including last week in this space), I have been telling anyone who would listen that the average frost season for Sacramento (the first and last dates of the garden year when temperatures may dip below 32 degrees) is Dec. 12 through January 27.  

The record dates for earliest and latest frosts for Sacramento, however, stretch even longer: Nov. 4, 1935 and March 27, 1898. (source: National Weather Service Office, Sacramento.)
Like many statistics, those average frost dates are written in sand, depending on who you talk to (and, of course, location).

The dates for the "frost season" are important to gardeners for many reasons, especially to determine when to gear up to protect those plants that may be damaged by the cold, especially citrus fruit and containerized subtropical plants that may need to get moved to a warmer location.
Another consideration: those frost season dates can help you ascertain how long to leave freeze damaged (or dead) branches on bulbs, perennials and shrubs. By leaving on those dead portions, the understory of the plant is given some protection to produce new shoots, especially near the base of the plant.


But are "average" frost dates good guidelines for the backyard gardener?

The National Climactic Data Center prefers to define "average frost dates" as those which include a 50% probability of frost, stretching out the chances of your "frost season" by several weeks.
For the gardener who worries about everything (as well as the weather geeks among you) here is a more realistic frost date chart for California:

Frost Season (50% Probability) for Selected California Locations

Bakersfield: Dec. 11-Jan. 31
Chico: Nov. 15-Mar. 20
Davis: Nov. 24-Mar. 4
Eureka: Dec. 15-Jan. 30
Fresno: Nov 25-Feb. 22
Lakeport: Nov. 2-Apr. 20
Livermore: Nov. 13-Mar. 29
Lodi: Nov. 16-Mar. 6
Los Angeles: rare
Marysville: Dec. 2-Feb. 9
Modesto: Nov. 29-Feb. 21
Napa: Nov. 26-Mar. 20
Nevada City: Oct. 15-May 17
Placerville: Nov. 6-Apr. 25
Sacramento: Dec 1-Feb. 14
San Francisco: Jan. 5-Jan. 8
San Jose: Dec 25-Jan. 22
Santa Rosa: Nov. 19-Mar. 25
Sonora: Nov. 12-Apr. 14
Stockton:Nov. 22-Mar. 1
Truckee: Aug. 16-July 11
Ukiah: Nov. 10-Apr. 3
Vacaville: Nov. 18-Mar. 19
Willows: Nov. 23-Mar. 14
Winters: Nov. 27-Feb. 17
Woodland: Nov. 26-Feb. 28

But, wait. What if you are the gardener who truly takes that seed packet statement, "Plant after all danger of frost" very seriously? What if a 50-50 chance of temperatures falling to 32 degrees or lower is too risky for you?  

Then heed this list of possible frost dates, which extends the frost calendar to include as little as a 10% chance of frost:

Bakersfield: Nov. 20-Mar. 3
Chico: Oct. 30-Apr. 23
Eureka: Nov. 15-Mar. 14
Fresno: Nov. 7-Apr. 1
Lakeport: Oct. 10-May 10
Livermore: Nov. 3-Apr. 27
Lodi: Nov. 2-Mar. 31
Los Angeles: Jan. 2-Jan. 3
Marysville: Nov. 14-Mar. 16
Modesto: Nov. 10-Mar. 20
Napa: Nov. 9-Apr. 20
Nevada City: Sept. 24-June 4
Placerville: Oct. 22-May 18
Sacramento: Nov. 14-Mar. 23
San Francisco: Dec. 1-Feb. 9
San Jose: Nov. 23-Feb. 19
Santa Rosa: Nov. 5-May 1
Sonora: Oct. 26-May 10
Stockton: Nov. 5-Mar. 30
Truckee: July 31-July 27
Ukiah: Oct. 25-Apr. 29
Vacaville: Nov. 4-Apr. 24
Willows: Nov. 8-Apr. 23
Winters: Nov. 13-Mar. 27
Woodland: Nov. 5-Apr. 1