I've no gardening experience; 'have redwood trees in shaded area but need large shrubs as hedge. Ideas welcomed
It would help to know more info.* Your hardiness zone and state if you are in the US would help.* I've not heard of zone 15.* Is that a sun zone?** Here's a zip code hardiness zone finder.
If you aren't in the US it would help to know your country.
How tall and wide can these shrubs get?*
Do you plan to put them directly under the redwoods?* You may have problems if you do because of the tree roots.* Can you move the shrubs out away from the trees so they aren't under the canopy?* Then how much sun would they get?
Full sun -* 6 hours or more
part sun - 4 to 6 hours of sun
part shade - 2 to 4 hours of sun
shade - 2 hours or less of sun
i dont think, actually i know that there isnt a such think as zone 15, maybe a typo?
zones in the US range from 2 in the extreme north to 11 in hawaii area but there is no such thing as 15!
Yews are probably your best bet, although they don't get that tall -- perhaps 5 feet or so. Viburnum also are good for shade, but no total shade. Otherwise, look to general shade perennials, such as hostas and a variety of others.
With no disrespct to Allison, yews can grow much taller then 5'.* It would depend on which yew you are considering.