Posted: 31/01/2014 at 13:35
Firstly I,would not worry too much about spacing...perennials can be lifted and moved anyway if tlook don't look quite right......I often move plants during the growing season amd when young they can be moved easily
You don't say which salvias.....however I assume the hardy varieties. They can be divided etc but they don't spread too widely.
I would put thyme and oregano in pots. Sage does get biggish quite quickly but regularly cut back will look compact. The purple,is nice. Tricolour is wonderful.
Lavendar and echinacea won't occupy too big a space.
Verbena bonariensis will occupy at least 50 cm by summer
All of,those plamts like it dryish with good drainage, sharp drainage, so you need to dig in grit, etc to lighten the soil. Can you mound the soil slightly to encourage drainage?
If your salvias are blue/purple I would keep well away from lavendar. They would compete not just in colour but also form, viz., erect, upright. A mound in between, like thyme,,would create comtrast if you decide not to put in a pot.
Yes it,is a narrow border.....planting one or two plants in a group of 3 would create a sense of depth. Bonariensis I would plant at the front....it would break up the heights there.
Which echinaceas do you want?
That fence......do,you want to plant something on it?
Your border is reasonably long so 2 bonariensis would break up any "lines"