You've decided on a "living wall" of plants as your preference in privacy screens. But which plants? A candidate for privacy screens that immediately comes to mind is shrubs, but you are by no means restricted to shrubs. If you do choose shrubs, you must further decide between shrubs that do well as hedges, versus shrubs that can be left alone, to assume their own, predestined form in what I will refer to as a "loose border" (also commonly called "mixed shrub borders").
Hedges are a good choice for privacy screens in small-yard landscaping, where space is limited. If the right choice in shrubs is made, and the proper pruning regimen followed, a hedge can be as precisely dimensioned a barrier as any masonry wall. It is in the hedge that the somewhat fanciful phraseology "living wall" finds its best justification. The trade-off, of course, is in the added maintenance. The amount of sun the area gets is also a consideration. Yews (Taxus x media) will tolerate some shade; but they do require good drainage.
Choosing shrubs for privacy screens, however, doesn't necessarily entail growing a hedge -- or sticking exclusively with shrubs, for that matter. The "loose border" is an alternative to hedges. While hedges are usually homogeneous, a loose border can be composed of different kinds of evergreen shrubs, as well as deciduous shrubs. If you are not limited for space, chances are you will find a loose border of shrubs, mixed with other plants, more to your liking than the formal austerity of hedges.
In planning for a loose border, select shrubs that will attain the desired height and width. To act as effective privacy screens, shrubs with dense growth habits have obvious advantages. Part of the attraction of the loose border alternative is low-maintenance. You are thus defeating the purpose if you plant shrubs that will outgrow the bounds intended for privacy screens, forcing you to get out there with the pruning shears and restore order.
Privacy screens taking the form of such loose borders should be layered for maximum effect. That is, put your tallest plant selections (probably tall shrubs) in the back row, shorter shrubs and tall perennials in the middle row, and your shortest plants in the front. In fact, building attractive privacy screens of plants means adhering to the same design principles one would employ in designing a perennial flower bed, including:
- Place plants of the same type in odd-numbered groups: 3 of this over here, 3 of that over there, for instance. Even-numbered groups suggest an attempt at a symmetrical landscape design that is out of keeping with the "loose border" look.
- Use repetition to "tie in" areas of the border. If, for instance, you planted a group of 3 delphiniums in one portion of your middle row, repeat (with the same color delphinium) somewhere else in that row.
The height of privacy screens is, of course, a primary consideration. On Page 3 we'll look at specific shrub choices for privacy screens, including their projected heights at maturity....