When I come up with a landscape plan, I usually have the long-game in mind. I like to provide plants plenty of room to fill in and do their job. It takes one to three years for most plants to mature, and even more than that for most trees and shrubs. Perennials and annuals are fairly fast growing. You can plant some Lavender next to an Olive Tree, and the Lavender will often triple in size within a year, while the tree may only grow a foot or two in that same year if you're lucky. Once trees and shrubs get established, and get more roots in the ground (occasional deep watering helps!), they can start growing faster.
Here's an example of one of my recent landscape designs, and how it grew in.
|AFTER: 5 Months after planting|
|AFTER: One and a half Years After Planting|
Above: One year later, and the van is much less visible through the hedge. All of the other plants, especially the Grevilleas in the center around the tree, have filled in as well. They are a little slower growing than the orange-flowered Gaillardia and the Blue Leymus grass, both of which started filling in right away.
You want a garden with a mix of these plant elements, and room for plants to spread, but this approach can take a little patience. This Podocarpus hedge will continue to fill in the gaps and grow over the next few years. Regular water for those first few years is essential to trees and hedges if you want them to get well-established.
See my post, "Lawn Removal in Glendale" to see how quickly a bunch of perennials and roses filled in when they were planted in Winter with awesome soil prep. Planting in Fall and Winter encourages amazing growth in Spring.