Question
what kind of fertilizer shoud I use on my taxus yews,when and how much? thanks

Answer
Hello Clifford

If these are established plants in the ground, they shouldn't need to be fertilized.  However if they are specimens that were put into the ground last fall they may benefit from a good general purpose liquid (or soluble granules) feed regularly (every two weeks or so) from spring onwards for their first year, after that they should be able to take care of themselves.  

In pots their needs are pretty much the same, except they will need to be feed for all the time they are in the pots.  You could also scrape some of the planting material out of the pots and replace with fresh.  Don't forget to water them regularly. Take a look at the root system every two years If you can) and repot if the roots have completely filled the container .

Gill