Joanna is one of Little Greene's quieter triumphs — a soft, stony off-neutral with a warm yellow-green undertone. The trick is to feed that warmth rather than fight it.
Lean into the earthy side. Warm woods, terracotta floors and unbleached linen are its natural companions, so before you've even picked a second paint, think about the materials in the room. Joanna wants to sit in a warm, lived-in space, not a crisp minimalist one.
For a tonal, restful scheme, put a soft sage on adjacent woodwork. Dulux Almost Pistachio (LRV 80.3) is a lovely light, muddy green that pulls the yellow-green out of Joanna and keeps everything bright and gentle — ideal for a north-ish room where you want lift without coldness.
If you'd rather have contrast, go properly deep and warm. Mylands Cigar BH.20 (LRV 11.8) is a rich tobacco brown that echoes the warm-wood story beautifully — cracking on a fireplace surround, a feature wall or joinery. For something with a bit more drama, Paint & Paper Library Blue Blood (LRV 16.4) gives you a deep, inky contrast on a panelled wall or a cabinet, and because it's a warm-leaning dark it won't sterilise the room the way a cold navy would.
Now the warning. Avoid cool greys. This is the single most common mistake with Joanna — pair it with anything that has a blue-grey base and it instantly reads as dingy, washed-out, spilt milk on the wall. Same goes for brilliant white trim; it'll make Joanna look dirty rather than soft. Reach for a warm off-white on the woodwork instead.
Practical tip: paint a generous A1 sample board and move it around the room across the day. Joanna shifts noticeably between morning and lamplight, so judge it against your actual flooring and curtains before you commit to the full scheme.