I agree that one option is as wuff stated. Another option, that is possibly too expensive for you, but that would look really good, is the use of lattice. If you purchase lattice that has the edging to it and erect it so that the height remains the same as the fence on the RHS, this could work. I would not recommend painting it as this would lead to regular maintenance. There are various sorts of lattice that you could consider. Don't put a climber on it unless you want the maintenance. If you wanted this extra care, you could espalier a climber like Star jasmine which is evergreen, or Boston Ivy which is deciduous.

There are a few bamboos that fit the bill, including Bambusa 'Alphonse Karr' and Bambusa textilis 'Gracilis' (slender weaver). Check out this site for bamboo info http://mrbamboo.com.au Facing north the bamboo will require a lot of water, and can look dry in summer. It is beautiful though. The suggested species get to about 4m. You can prune them if you are dedicated. Otherwise hedge and front plant, or a climber if you construct some form of support.

If you could remove the existing hedge and then start the whole replacement hedge from scratch would look so much better. There are Lily Pillies that grow 1 to 1.5 metres wide that you could consider. And take them along the back fence as well to enclose the yard. This will give a structured 'finished' look. These will work with the part shade. Is this hedge on the southern side of the home? Lawn could be an issue to grow here because the closer to the house the more shade. And you don't need to start with big plants. Natives grow far better from a 14 to 20cm pot. Just make sure that the height and spread are what you want as there are a lot of lily pillies on the market. Better to get Acmenas than Syzygiums. Alison

You look to have a lot of space there, so there is great opportunity to get some good layering of plants. You also have some great 'borrowed landscape' with the trees over the fence. You can start with a background row of evergreen screen planting to hide the fence. I'm a big fan of Syzygium or Waterhousia. Both are Lilly Pilly varieties. Waterhousia can get big though, so be mindful around a pool. Syzygium 'Bid Red' or 'Bush Christmas' are both good varieties of screening plants. Once you get the background in, you can locate feature plants or even some trees. I'm not sure where you are located, however natives are always a good bet. Grevillea 'Moonlight' or Callistemon 'Kings Park' are great larger flowering shrubs and provide stunning colour difference. Then you can get some good foreground planting with lower shrubs and grasses. You can mass plant Lomandra 'Katrinus', smaller Grevilleas, Hebes, or even Dietes for a more formalised look. It all depends on the style you want to achieve. Just make sure the plants suit your climate and soil. It looks quite sandy!