A period of success, good fortune etc.
My flower border is going through a purple patch at the moment:
|Clematis and alliums|
|The whole border|
I love to see the garden changing through the year - from the yellows of the daffs and the blue of the forget-me-nots earlier in the year, to the current purples, and onto the reds that will predominate when the roses get going later in the summer.
It's a kaleidoscope of colour - every month something different.