Hops, but also false Mandrake look really good as decorations.
But it’s a different thing making a decorative plant from a real plant: usually real plants in a planter are bigger and they look better than a decorative plant.
You can place seed + compost in the planter… but remember you just need the planter and just 1 plant to have it looks like full of vegetable life !
Also I love to mix style in my base, I find aquilonian fences looks really nice and you can place khitan green dragons on it, I love them (your GPU and any ther player near your base do NOT because the lag, but it’s totally worth it if you ask me 
)