As you all know, our patio is L-shaped.
Our new herb bed, which encloses it, has weep holes on the outer side. Our builders advised painting it with a bituminous waterproofing compound to prevent damp when people might be sitting on or next to it.
This kind of planter needs to be well-drained, as the soil at the bottom tends to become sour if left to its own devices. We used broken brick and tile at the bottom, then Re-Agg (recycled concrete in aggregate-sized particles). A special planter box mixture went on top.
The white spiky thing in the middle of the bed isn't an aerial: it's electrical wiring for garden lights.
The fun part was planting it, of course. So far, the herbs are Coleus amboinicus, chives, savory, sage and thyme, and Russian garlic (the last after I took the photo). The flowers are a deep-blue lobelia and Veronica 'Oxford Blue', and my sons' strawberry plants.
At the bend are two plants. The first (just visible at bottom right) is a choko, which I hope will grow over the pergola fast enough to give us shade this summer. The rosette of large leaves is Echium candicans, Pride of Madeira. It should grow to fill the corner and produce wonderful blue flower spikes. I fell in love with this plant when I first saw it in Mildura, and again in the Melbourne Botanical Gardens.
I had to make one more change to the garden bed after the chickens discovered it and scratched the mulch up everywhere-- it now has a layer of light mesh over the top! Not attractive, but at least the plants won't be uprooted every time my back is turned!
I'm looking forward to adding a few more herbs: my rosemary has yet to be added. Oregano, marjoram and tarragon are definitely required, but there's a whole thyme family to consider...maybe a pineapple sage... bee-balm... I've always fancied a houseleek to protect against lightning... maybe I'd better stop now...