I would use the Cypress clippings in an instant, since they have insect repelling properties, like cedar. Yew is a little more problematic, since I seem to remember that they inhibit the growth of other plants, but I am having trouble tracking down references to that.

Hello. You can put mulch down 'green', or pile it in a heap, where it will slowly 'cook' to an even brown. All parts of a yew tree, except the red outer flesh of the berry, are highly toxic. The toxin does not reduce when the leaves die or dry out. Gloves should be worn when handling either the leaves or the wood. Horses particularly are susceptible. I cannot find a reference to the leaves inhibiting other plants, as such, but a tree surgeon friend said you can definitely expect it to act as a weed suppressant, which would be the same thing. All the conifers, pines etc make excellent weed suppressants under hedges for instance, or as natural paths. Hope this helps.

Thankyou both for your help. By the amount of mulch I'll have when I've finished shredding, I wont have any weeds in my garden next year. :) I wish.

Well, if nothing else, a good mulching sure makes weeding easier! : )