perennials

I'm new to perennials and would appreciate any advice. Last year I planted some bear root cuttings, amongst others were hollyhocks,sea holly and erinacea. Each hollyhock sent up a single spike which reached almost 11 ft in height.

Generally if I were to cut back perennials to a shorter height would this encoiurage additional stems being formed.

Certain perennials benefit from something called "the Chelsea Chop". It's done around the time of the Chelsea Flower Show. If you "Google"  "the chelsea chop" the RHS site comes up which tells you about it. I tried it on some very tall yellow rudbeckias and they grew bushier and not so tall. Hollyhocks are meant to be tall and I don't think it would work for them. A lot are biennial and you'd just lose the main flower spike.

Peter, hi. I agree that hollyhocks want to grow really,tall. You could plant a few together but they aren't a true perennial and usually get diseases such as rust. For bushy,long floweringerennials what about Veronica varieties....lots of blue spikes in summer. Go well with your echinaceas. Delphiniums which are true perennials with tall spikes of blue, white etc. and are "bushy" and if cut back will flower again, as will,salvias, lupins, and most plants if cut back via dead heading. Hollyhocks tend not to,grow as tall following year anyway but still be basically single stemmed.....for me anyway