How little can you have and it be a garden?
Remember Gertrude Jekyll's "....the first thing I consider, when planning a garden, is what to put on the house."
.
For ease of maintenance I prefer espaliered woody shrubs. No wires, no trellis.
.
House & terrace, above, are vanishing threshold.
.
Garden & Be Well, XO Tara
.
pic via Half Pudding Half Sauce.