Unfortunately, no single website that I know of will produce such information. Not sure if I can think of any single text that will do the same, either. Pruning times, techniques and degree can vary considerably from plant to plant. Conifers generally require and should receive minimal pruning and deciduous shrubs may or may not require any regular pruning - it depends :-) Groundcover or carpet roses like the Knock Outs also require very little pruning compared to hybrid teas or shrub roses.

It may be best to research each of your plants individually to determine what is the approved pruning regime for each. And it's good to know the basics about pruning anyway, as proper pruning techniques apply to all plants. The American Horticultural Society has published an excellent pruning text: Pruning and Training. Extremely well illustrated and very easy to follow, but primarily oriented on trees, shrubs and vines. It also provides some very detailed-by-plant pruning information, so a good investment all around.

Non-evergreen ornamental grasses like the ones you list are typically cut back to 4-6" in late winter or early spring, as they are desirable for winter interest. If the weather makes them too messy, they can be cut back earlier.

Gardengal,

Thanks for the reply. I'm beginning to think you're right. There IS no one single source of information. Individual plant research seems to be as good as it gets.
Hard to believe there isn't a one stop shop for plant care.

Again, thanks for the well written reply :)