The general rule is after the first hard frost and before the buds begin to swell; but I don't know what kind of tree you are pruning. Pruning after the frost means there won't be bugs around to get into the cut ends; before the buds swell, because once the swelling starts, the roots have already put energy into branches that you are going to cut off. The cut ends will harden off in winter.

another basic.....I am in the southern calif area....temp may drop to 36 or above.....if i put some plants under a canvas tent that hs open sides will this help them when it gets cold....i read somewhere that as long as the plant is covered from the top that frost or cold wont get on the plant....to me cold is cold and it doesnt matter if there is a top or not.....just asking tho...

oorah

these are fruit trees...in the ground and containers...so what you are saying is that the cold wont harm the tree when its being pruned because of its dormancy...thanks for your response

oorah

I agree, cold is cold; August is cold enough for me; it is one of the reasons I live in Guatemala, the Land of Eternal Springtime. I don't know of any advantage of covering your trees in So. Calif. 36 degrees F. won't harm anything... except maybe Mangosteens, of which I have 3. The cover likely will only protect insects that I don't think you really want to help. At your temperatures, I would seriously consider spraying or incorporating a soil insecticide (Furadan, Vydate,...) on the soil around your trees during the Winter to kill any insects that overwinter in the ground and climb back to attack your trees in the Spring.

thanks Johnmerr I have several tropical trees....pappaya...mango....etc....what temp would harm these trees...

thanks

oorah

I don't know. I have mangos, papayas, sooo much more at my lemon farm; but they grow like weeds in their natural environment. For you I think a greater issue is light/latitude for fruiting more so than cold damage.
Please don't quote me on that, as I have no real life experience in growing tropicals in So. Calif.

Watching some Dave Wilson videos,they are pruning summer or just about anytime.Brady

Pruning is a pretty widespread topic; so much depends on what plant, what climate, what purpose, etc.
In a lot of climates some Summer pruning is also required; but I think the question was about trees when they are dormant.

Johnmerr....do you have and of your fruit trees in containers.
you crack me up when you say....August is cold enough for me....I will drink to that....but a good cold is also good for the body....

oorah

No, only my nursery plants are in containers or poly bags.
I have a small farm with 3,000 Meyer lemons plus a plethora of other trees; I bought the land in Feb. 2010, so all my trees are young; but they produce quickly here.
There is a forum here on the Garden Web for container growing and there are lots of experts who are very helpful; there is also a tropical fruit forum, just click at the top of the page for "Other Forums".