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!

Do you have a budget in mind? preparation is the key to success, I would consider maintenance how much time do you have to spend on the garden, hedgers are great but to look great require a fair amount of consistant care. Firstly I would do a ph test on the soil, that will determine what you will be able to grow easily, you then need to consider light, how much sunlight does the area get, it looks to be quite compact being a driveway, drainage is another issue as from the picture it looks the have quite a slope to the area, the laws of gravity will have an effect on water infiltration, so plants at the highest point will have less water and the plants at the bottom will be subject to being water logged. I would be mindful of plants with thorns being such a small area and getting in and out of your car scratches are inevitable and dangerous for little kiddies eyes etc. Australian natives are great but most wont tolerate water logging and most prefer alkaline soils and wont do well in heavy shade. My choice would be to find a climber to suit the area there are many to choose from I love Hardenbergia Happy wanderer, Jasmine, honeysuckle and stephanotis just to name a few. Camelias are also something to consider but again all comes down to your soil ph.

Thank you so much JE and Julie! The existing street front hedge is Murraya but is twiggy where we need it most - could be age, except that where it faces north it’s thick, so I’m guessing sun exposure is an issue. Hopefully the viburnum will be better!!!

Hi, have a look at catalpa bignonioides Nana it is a magnificent standard , a real feature and grows beautifully in Melbourne, would look gorgeous in your garden.