Thursday, August 7, 2008

Fall Pruning

 A - "Keeping it simple!"
 August, (and perhaps the first few weeks of September) is the best time to prune the Apricot and Aprium trees.
 With your Pruners and Loppers remove any "suckers," cut out Dead, Deformed, Damaged, and Crossing shoots and branches.
 Remove the "Water Sprouts." These are the paradoxically very green and healthy looking shoots, that you might think are "good"  to save..... they're not! They usually grow from interior branches, are this years growth, and grow straight up to the sky with no branches (they will rarely have any fruit!)
 The lateral branches (reach out with your arms) will have the shoots with fruiting spurs. For the ones that grew this year (green bark) visually divide the shoot into four sections, starting from the origin,.... cut off the outermost one, of the four sections (that is: reduce the length by 20-25% of the shoot's length).
 Try to cut the shoots or branches at a point about 1/4 inch out from a bud or node. It's best if the bud (node or shoot) is pointing in the general direction that you want the branch to grow (e.g. not pointing down.... or towards the central/interior area of the tree). If you have to  remove a branch entirely, make the final cut just outside of the little "collar" where the  Branch originates from the Trunk. Don't leave  a "stump."   
 B - "More in Depth:"
 Post harvest, or late "summer" pruning is particularly useful if trees have been growing too vigorously, and are getting out of control (too high).
 Summer and post harvest pruning has a modulating effect on tree growth. On the other hand: Pruning after leaf drop is a great stimulant to spring growth!
 APRICOTS  should NOT be pruned any later than early September. So this is the last time you can prune them before mid-summer next year.
 Apricot pruning wounds are subject to a disease (Eutypa Dieback) the organism is spread by rain. The pruning wounds need 6 to 8 weeks of dry
 weather to properly heal.
 The Water Sprouts can be thought of being like your Appendix.... it probably once did.... but no longer has any real function. Probably genetically left over from when the tree had to "get up there" to compete for light from its surrounding trees. These shoots rarely if ever bear any fruit.
 You also want to remove shoots growing towards the center of the tree. This allows air to circulate and sunlight to penetrate to the interior.
 If you shorten the shoots (the 25% number), you'll be keeping the fruit more towards the trunk and major branches and reduce the chance of breakage. The remaining spurs will now bear larger and healthier fruit.
For all the trees, it's a good time to remove branches that have broken under the weight of fruit
("really herb, where have you been!....... Some Orchard in Fresno!")  ........Just wait your trees will get there. 
C - "Some more Background:"
  - A good time for pruning over-vigorous trees is after harvest, before dormancy. The other trees are best pruned later,
in the Dormant period. Broken or cracked limbs or branches (some say a Shoot becomes a branch when it's 1 yr old) are a place for disease entry (like any wound). It's best to remove those branches, back to a proper location. The area of a bud (those little swellings, or a leaf node) contains the hormones necessary for proper healing. The smooth sections (internodal area) will not heal, they'll just die back to the bud, and you've not accomplished much.
If the bud (or shoot) is pointing to the direction you want the limb to grow, your cut will also have "training" value. The Branch Bark Collar, at the origin of the branch, has the healing potential to close over the wound (take a look at some old pruned trees). A stump that protrudes will heal poorly, if at all. Pruning paints or sealers are not recommended.    It's far better to place the cut in an area of good natural healing.
Dead shoot ends (black and really dry) may have been invaded by a borer, or bacteria. The dead, wilted and shrivelled leaves may still be hanging down and attached. Prune these shoots off (don't cut through the dead part, go back a ways to where the shoot is normal looking. Diseased branches may have a bacterial or fungal infection. These branches will often have an area of disrupted bark, and oozing a somewhat resinous, brown or black sticky fluid. Cut these branches back at least a foot from the wound, so that you are in healthy looking wood.  (Nice intact bark and cambium layer, with uniform and light cream colored sap and heart wood (not stained brown or black).
When pruning out dead twigs or branches (particularly if they look diseased; oozing, crusting) leave a healthy margin of normal looking branch (up to about 12" if you can) to get well beyond the bad part.
Cut out crossing branches, the areas where they rub are subject to wounding and disease entry. Leave the bigger, or better oriented branch. (Or make an "executive decision" and leave the one that YOU like best. Hey..... you're doing the work!  Michael understands.)
This is also a good time to prune the Citrus trees of any dead branches or twigs, and any branch ends that are dragging on the ground. When you have access to the trunk, renew the "Tanglefoot." If you can keep the ants out of the Tree you're probably 90% to good disease control. Often, nothing more is needed. (Ants kill the Beneficial's larvae that are feeding on the Pests...... that's not good)
Except for the Apricot (remember?), you will probably want to do some Winter Pruning on your trees......
but more about that in the next newsletter.
And remember! with any diseased branch... or going from Tree to Tree..... always sterilize your  pruners between cuts, by dipping  the blades in 70% or 90% Drugstore Alcohol (Isopropyl).     When you're finished, wash off the pruners and spray or  apply  a protective oil. Afterwards  I always resharpen my Pruners, and spray metal parts with an oil protectant like "WD-40." 
Cleaning your Tools between "Cases", is just like washing your hands. BECAUSE..... You're Doing Surgery!  And wear your goggles!!
Hint   For Orchard Instruction, Pruning, Training, or Tree Care: Fill out the Commonvision request online, for a free Workshop at your School Orchard. These are put on by the Master Gardener Orchard Team (not yet available in all Counties).

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