Posted: 02/07/2014 at 08:31
Ah snowdrop, you already have bonariensis I see.....
I grow salvia guaranitica and salvia uliginosa. Both are tall long flowering blue plants. However, there is a big difference......uliginosa requires more moisture. If,your ground is moisture retentive or you can add water occasionally, this is a mighty attractive plant. Blue flowers with white tips, graceful, erect and easy. Guaranitica has vsrieties with darker or lighter blues but grows in dried soils.
Acomitums are worth checking out too.....I grow a couple of varieties. My fav is Stainless Steel with lovely blue flowers. Aconitums are bushy long flowerimg perennials that thrive in a little shade.
Consider though grasses there.. Tall grasses like Calamagrostis Karl foerster or vsrieties of miscanthus will add drama, impact, flowers and movement for you