I would plant along the fence line trees like Magnolia (Little Gem) or Hibiscus, and there where the wider part - low shrubs under the trees or stripy Dianella. All these plants and trees are hardy and easy to take care of. Trees don't drop the leaves and slow growing. Otherwise you can place pots with bright plants (Frangipani grows well in the pots). You can mulch the soil under the trees or put some pebbles or gravel like I did (see the photos).

Pennywort is a sign of bad drainage in the garden beds themselves. So rosemary is a bad choice. Your grasses are also not a good choice - I fear that they will become weedy in your poorly drained soil. You are getting water coming from higher up the slope and the wall is now an obstruction to the flow of water. If you plant good sized gums along your fence-line, these will help to soak up some of the water coming down the slope. And this water may not be above ground, but seeping through the soil. I assume that its clay? I would be using ONLY native plants because they are better suited to the soils of your area. Whenever people have problems with drainage in their gardens, this is the ideal time to use natives. But choose varieties that don't set seed. The grassy plants that you have selected both set a lot of seed - which then become weeds! Plants like bottlebrush, melaleucas - and use the smaller growing forms, leptospermum [tea tree] etc are all good choices for poorly drained areas. But be warned that you cannot use roundup around young natives so hand weeding will need to be done. Clear the area well BEFORE you do any planting and get on top of the pennywort. Maybe retain your camellia - I hate the thought of removing it! But if its not looking good, remove it as it will drag your whole finished product down. Don't use black plastic - its really bad for the soil. Your vinegar spray sounds fine - is this with Epsom salts?. Boiling water is also pretty good as well. But you need to keep doing it regularly. Gardening is not easy in the initial stages, but if you persist, the hard work does eventually pay off!

Make sure you have good soil, add mulch, water crystals to retain moisture, slow release fertiliser to promote healthy growth, a watering system is a great way to save time and keep plants looking great. You could try for a tropical look by planting golden cane palms, elephant ears, the gorgeous Rhapis is elegant and gives good dense coverage and beneath trees the lush Xanadu’s foliage is beautiful, adding to the soil as above will maintain the garden beds in top condition.

Thanks Julie. I'm pretty sure I have knocked the grasshoppers off, just need to see what can be done for those tiny black ants that seem to be in the stems. Would you recommend any particular thing for refreshing the soil? Sorry I am a novice at this. The Xanadu plants look really nice and it was something I did see when Googling as a low maintenance plant. Would you recommend anything for being around fruitless Olive Trees? I was thinking of pulling out or atleast thinking the plants under those trees. We already have a little bit of rosemary and lavender at the front side as most websites recommend those.