Here's a question I get a lot. "Hi, Randy! My house backs up to a retaining wall along a major thoroughfare, and while I'm thankful that the wall blocks traffic noise, I don't like looking at it. Can you recommend a plant or tree that will hide it from view?"
I usually suggest a handful of plants or smaller trees that can accomplish this, and for years my number one recommendation has been the Texas wax Myrtle. Next in line would be the Elaeocarpus decipiens, affectionately referred to as the Japanese blueberry (left). Let's look a little closer at that one.
First, let's get one thing straight regarding this "blueberry." Despite its name, this is not a tree that bears edible fruit in any way, shape or form. So, just wipe that thought from your mind. It is, however, a uniquely shaped evergreen which can handle light freezes and pathetic, alkaline soil.
It's also relatively new to the Texas landscape market - it's been used successfully for only about the last 15 years.
From a distance, it looks sort of like a coppertone loquat, with its dark-green, lustrous, leathery foliage. But the Japanese blueberry grows more upright. And like a red tip, it can grow to 25 or 30 feet at full maturity, making it a wonderful upright-growing evergree shrub or tree that solves many privacy hedge issues. And when pruned consistently and correctly, you can also maintain them at specific sizes and shapes. If you've ever been to the Kemah Boardwalk, for example, you'll see them shaped in a columnar fashion.
The first specimens introduced to Houston about 25 years ago didn't make it through the freeze of April 1, 1989. But since then, more advanced varieties have survived the freezes of January 2010 and February 2011, suffering only burnt leaf tips.
As I noted above, they have been shown to handle slightly alkaline soil and areas of partial shade. But they grow best in a moist, fertile, slightly acid or neutral soil and in full sunlight. That means ample sun throughout the day, but they don't need all sun, all day. The Japanese blueberry will produce greenish-white flowers and olive-like fruit usually hidden among the foliage. The flowers can be fragrant in mass.
But here's one negative. The berries, while edible for wildlife, can be somewhat messy when they drop on paved surfaces. So don't plant them near driveways, sidewalks, patios or porches.
If you'd like to research other shrubs and small trees I have long recommended to hide fences and walls or for privacy hedges, here is a short list:
Texas wax Myrtle
Eastern Palatka holly
Nellie Stevens holly