Ask Mr. Smarty Plants

Morella cerifera (Wax myrtle) is a nice shrub or small tree that can get up to 12 to 15 feet in height. It is evergreen, has fragrant flowers as well as fragrant foliage, and attracts many different kinds of birds. It is a fairly wispy open plant, so it shouldn't be casting too much shade on your neighbor's grass, but in the interest of good neighborhood relations, you can certainly prune it back to 8 to 10 feet.

Wax myrtle is very forgiving of pruning, and we saw several different suggestions when we searched on the Internet. If you do it right away, before new growth starts to show up, you can prune them now, don't wait until it starts to get hot. Then, after that, prune it a couple times of year to help it regrow into a hedge size and shape. Don't get too severe and boxy in your pruning, as that will ruin the natural character of the plant. If you are getting berries on your trees, that means you have female trees and there are male trees of the same species in the area for pollination. It is not surprising that you got those trees coming up voluntarily. So many birds love the berries, eat them, digest them and re-issue them with a little fertilizer at no extra charge, that they will grow volunteers all around. The wax myrtle doesn't sprout particularly aggressively, but it wouldn't hurt to pull out volunteer seedlings when you see them, before you get a wax myrtle thicket. The wax myrtle really grows better a little farther east in Texas than Austin, preferring a slightly acidic soil which it doesn't find in our alkaline clay soils. However, it sounds like yours are doing just fine.