Verbena bonariensis and Echinacea spring to mind. There is discussion recently and an American book by Tracy DiSabato-Aust (The Well Tended Perennial Garden about £20) about cutting back tall plants before they flower. If done at the right time the plants are shorter and do not need support. The flowering period is the same but the start and end is delayed by only about 2 weeks or so. There may be more but smaller flowers.

For example, in her book, Helianthus salicifolius unpruned was 5 foot, but when cut in half in June before flowering grew to 3 foot with no delay in start of flowering.

Great tip. I don't mind about things being tall, as long as they don't fall over, but I wouldn't mind tinkering with flowering times, in order to stop things flowering in August when I'm usually away on hols.

Maclaya cordata is tall and never seems to fall over, though it does lean towards the light!
Lythrum salicaria.

Have you tried those green wire supports with criss-cross centres, they stop most things flopping if you remember to put them in place early enough. you can get them up to about 18" diameter with legs about 2'6". Very helpful for plants like Gaura. They are also good for growing plants like geranium wallichianum which will grow up through and cascade over the edge.

There is a bidens i grow which grows to 1m tall and makes a lush clump quite late in the season - not the hanging basket trailing bidens but a pale yellow, not unlike coreopsis verticillata. Also, cosmos seem to do OK,as do my rudbeckias and heleniums. I do tend to pack stuff in together too which helps. Oh yes, annual cornflowers look terrific with grasses, as do corncockles and ox eye daisies (but this is meadow type planting, i guess).

Japanese anemones and ferns.

Many perennials that grow unsupported in drier and more sheltered parts of the UK get wiped out here by wind and rain just when they're coming into flower - it's the extra weight and sail area I suppose. Even the sturdy Japanese anemones get a very serious lean, although rarely knocked entirely flat. Geranium endressii sometimes gets flattened too and that's not easy!

I'm going to try the method recommended by the aforementioned lady - I think the extract in 'The Garden' must have been from her book - but in a modified way. Instead of cutting back later in the season I'm going to try when the growth is only a few inches high in the spring. This way there'll be no cuttings to clear up and it will be easier to move about the borders. We try to grow later flowering perennials anyway as we have so much in flower in the spring, so it's doubly disappointing when they flop at the height of their flowering season.

One plant that has survived our recent very stormy weather with only a very slight lean to windward is Patrinia villosa, from Japan, white-flowered instead of the usual yellow, and a light and airy 'see-through' plant. I will certainly be growing more of this one. Chelone obliqua is usually pretty good too, though slightly earlier flowering.

Good luck,

Maurice.

I don't remember anything growing more than about a foot tall in western Scotland :) A slight exaggeration perhaps, but things do tend to huddle down for shelter. Try a shrub if you absolutely don't have to have it die to the ground each winter. Or some grasses, not my favourite but you don't have to stake most of them.