Cooperative Extension San Joaquin County
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Cooperative Extension San Joaquin County

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Palm Tree Care

I live along an historic boulevard of beautiful Canary Island Date Palms,  Phoenix canarensis.  They are really majestic but they do drop a lot of fronds during much of the year.  Anytime there is a breeze, one can expect to see the large fronds or flower clusters littering the ground around the base of the trees and  the street.  The dropping fronds are not really a huge issue in our area because the road is quite rural, and infrequently traveled.   However, there are many plantings that are considered quite hazardous because there are a lot of cars and pedestrians under the trees.  To reduce the possibility of injury, there are those who will drastically prune palms just to prevent the fronds from dropping later.  I call this "preemtive pruning".  Excessive pruning can be quite harmful.  It reduces the surface area of the “energy system” of the leaves thereby weakening them.  Excessive pruning can also open the palm up to serious decay and disease issues.  The key to proper palm pruning according to palm expert Don Hodel, UCCE Environmental Horticulture Advisor in Los Angeles County, is to never prune the fronds off above the middle of the horizontal plane of the head of the palm.  If you were to think of a clock, the fronds located below the 9:00 and 3:00 O’clock position are fine to remove.  Don’t prune off any fronds above that point. 

When you do prune your palm trees, the ideal time is when the weather is dry to prevent disease problems from occurring. 

 To learn more…..

Posted on Thursday, August 27, 2009 at 12:47 PM

Apricots Best Pruned in Late Summer to Prevent Dieback

Apricots and cherries can have a fairly short lifespan in many climate zones in California due to a disease called Eutypa.  This disease is able to invade through pruning wounds especially during the wet winter months.  This disease causes limbs or twigs to wilt and die suddenly in late spring or summer with the leaves still attached. 
The bark may appear dark with an amber colored gumming on the branches.  

To combate that the disease and reduce the potential for Eutypa to infect trees, you should begin pruning your apricot and cherry trees during the later part of summer and early fall at least 4-6 weeks prior to rainfall.  However, realize that you may be opening your trees to sunburn with summer pruning so be sure to paint exposed branches with a diluted white latex housepaint with 50:50 water to paint mix.  Also avoid pruning if you are going to have an extended period of 100 degree plus weather. 
To Learn more.....
Posted on Monday, August 17, 2009 at 4:20 PM
Tags: apricot (1), cherry (1), diseases (2), fruit trees (1), home orchard (1)

Spotted Spurge is the Scurge of Many Gardeners

Spotted spurge is one of those weeds that seem to defy our best efforts to control it.  It is a low growing plant that develops into a dense mat that can overgrow turf and compete with ornamental ground covers and annuals.  It can be characterized by its dark green tiny leaves, which often have a red spot about mid way down the center leaf vein.  The stem, when broken, exudes a milky latex juice. The plant has a central taproot system that is capable of extending more than 2 feet into the soil. The tiny pinkish flowers abundantly produce a three-celled seed capsule that is 1/16-inch long or less very early in its lifecycle.  Spurge can be very difficult to control once it becomes established so prevention is key.  However, once it invades there are some things you can do to reduce its impact.

First, consider a heavy mulch layer.  For more.....
Posted on Wednesday, August 12, 2009 at 2:29 PM
Tags: ornamentals (1), spot (1), turf (2), weeds (11)

Jumping oak galls on valley oaks

This time of year, it is not uncommon to see the valley oak trees (Quercus lobata) with their leaves yellowed and splotchy with numerous small seed like balls on the underside.  These are called Jumping oak galls and they are made by a small Cynipid wasp larva (Neuropterus saltatorius) that is developing inside the gall.  Don’t worry-the wasp doesn’t sting humans.  In fact, you would be lucky to actually see the critter.  While the galls do cause some defoliation, they are not particularly harmful to the trees.  They may cause some serious leaf loss in some years and this year seems to be one of those years.  The adult female wasp, in order to be able to create a gall that contain an egg, must sting the leaf at precisely the right time.  If the leaves are too fully expanded and hardened off, the galls will not form.  That is why you might see one tree with millions of these galls and yet the one nearby might not have any.  Their foliation times may be somewhat different.  There are many types of oak galls including yhose that look like chocolate kisses and some that look like apples, and still others that look like horned or fuzzy balls.  We do not normally recommend any type of control of these insects.  However, some research indicates that if one leaves the infested leaves on the ground, the parasites of these little wasps are not raked away and it may moderate the population over time.  As well, there is more “mulch” on the ground around the trees, which is a good thing.   

One of the fun things to do with the galls as they are beginning to fall off the tree is to just bring them into the house.  As the galls warm, they begin to jump and wiggle around and make a snap crackle and pop noise….

To Learn More….

Posted on Monday, August 3, 2009 at 11:41 AM
Tags: Oaks (4), Pest (4), Quercus (1), Trees (2)

How Can I Control Creeping Wood Sorrel (Oxalis) in My Lawn?

  The lawn, from a distance, looks lush and green.  When walking across it, however, the exploding seed pods of the densely growing oxalis spread seeds across my boots and across my lawn.  In one year the newly planted cool season turfgrass has become an oxalis or creeping wood sorrel lawn. 

Creeping woodsorrel is a major weed in turf, ornamental plantings, gardens, and nurseries. Uninfested landscapes can become contaminated if infested container stock is used in plantings. As seed pods mature and expel seeds, creeping woodsorrel spreads from container to container, flower bed to flower bed, or across ornamental plantings and lawns....

Learn More.....

Posted on Tuesday, July 28, 2009 at 3:24 PM
Tags: herbicides (1), lawn (3), oxalis (1), turf (2), weeds (11)

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