Any fragrance from a plant that scents the air is usually coming from the flowers rather than the leaves. There are plants with fragrant leaves, but these only smell when bruised or crushed. Given that most shrubs don't flower for that long, you won't be able to have fragrance all year round from one plant. Obvious ones are honeysuckle (climber though) for summer, jasmine (summer climber again) Elaeagnus varieties (fragrant flowers about now) Sarcoccoca varieties (fragrant flowers winter), scented rhododendron/azalea (can't remember the name) for spring.

Wysey if your sceptic tank is smelling there is something wrong and you need to get it checked. We had sceptic tank drainage for years and it never smelt. Could you have accidentally put something in that has upset the bio-system?

I agree with Moon - if your septic tank is smelly, then there may be a problem with it. It might be leaking into the soil - obviously not good. I'd get it checked by a professional if I were you. Get the stink sorted and there are any number of shrubs you could plant to mask it, but make sure that easy access is kept for when it needs emptying / maintaining.

Thanks everyone, I should clarify that the septic tank does not smell continually but occasionally you will get an unpleasant smell now from it.

The plan to improve scents around the septic tank are to minimise these as and when they occur.

you probably already know this but you should be sparing with stuff like Domestos and use the Eco-friendly washing up liquid and soap powder. Mine never smells.

The shrub I consider best for scent, at least through the winter, is Viburnum x bodnantense 'Dawn' - if you google it you'll find lots of pictures. It flowers throughout winter and the flowers smell gorgeous. Mine's in sun tho - not sure if it would do so well in shade - would depend on how heavy the shade is. A good one for shade tho is Sarcococca confusa or Sarcococca hookeriana, both of which flower in winter. They have tiny inconspicuous flowers, but are evergreen and smell lovely. For summer, roses do ok in partial shade. Also Mahonia x media.

I forgot about the shade bit, Wysey - that lets out jasmine and honeysuckle I mentioned, they both like sun..

Do you like the scent of the leaves of Choisya ternata? I do - but some people don't. It might not produce many flowers in shade, though. It is an evergreen.

Yuk, no, Spritz, horrible smell from choisya leaves, like cat's wee.

See? I love the scent - and.... Bamboo doesn't! (No, it doesn't, Bamboo! )
It's a 'spicy' scent. :-))))))

I like the smell of the flowers of C. 'Aztec Pearl' ...no good in the shade tho.

Thanks everyone, a few possibilities for me to check out - will have to smell the Choisya ternata leaves and make up my own mind...... no idea yet!!