The Ideal it me to take a clone is at some point late in the plants vegetative growth , because the cutting will root faster and have far better odds at surviving and the plant having the cutting taken from it will recover in a few days as if nothing happened with minimal to no stress where as in flower it's shoot development is done so what ever you take away from it is lost for good.

 Now we have heard the ideal time i guess it's time to talk about when is too late. It is my personal opinion that there is no too late , however some plants are hard to clone at the best of times and these you shouldn't expect miricles from those in particular,  as a whole though  you can clone a plant provided the tissue used for the cutting is alive and healthy.
With that said the further into flower the plant goes the slower it's root development is which in turn increases your odds of loosing some but the important thing in the end is that it is possible and you haven't necceseraly lost your favorite strain just because you have let it flower. It just takes more care and numbers to ensure you save her. Here are a few tips to help you increase your odds if your  having to save a plant that has passed it's prime cloning period.

• Flush the plant being cloned a day or two before cloning
  
• Remove any flowers from the cutting
  
• Ensure that your rockwool is soaked for 12 hours in ph adjusted water ( pH of 5.4 is sugested to soak cubes as they are naturally on the alkaline side of the pH scale)
  
• Take more clones than you need ( the more you have the higher your odds of saving it are cause chances are you will loose a few )
  
• Use rooting hormones to speed root production
• Additives like Rhizotonic or similar can be very helpful
  
• A small amount of co2 enricher can work wonders to speed up the process I had clones taken in week 6 flower completely root in 9 days 
  
• Give the clones at least 2 hours darkness every 24 hours ( this will help the plants general health and also assist rooting )

The best example of a recovery online that i have seen is in Postmans thread where he saved a  proven mother from the bin after harvest !! Click the link bellow to watch them go from rubbish to mother again

Cuttings from harvested buds

Thats all from me , this tutorial will continue to be expanded with time, happy cloning

 Tutorial written by Pure for cannanation.com/ozstoners.com