Why Designers Plant in Groups of Three

Why Designers Plant in Groups of Three

Language for Design Series

Have you been told to arrange things in groups of three? Have you ever wondered why? Have you mentally accused the nursery specialist of just trying to get more money out of you? You are not alone. However, there IS a reason for threes, and the nursery specialist really is trying to help you achieve a good design, not just part you from your cash! (

Photo left: good design makes for happy critters.


First of all, there is the Principle of Repetition. Repetition, all by itself, creates a comforting, reliable feeling. This is why a road flanked with trees on both sides is so appealing. It is predictable, which creates comfort. If you were to plant an endless series of a single plant (OK, maybe not endless) along a path, it leads you along because of its illusion of safe harbor--you encounter the expected. This does not happen with the planting of a single specimen.

Repetition can be more random--for instance, as I have mentioned


, in nearly every bed in my home garden you can find a grass-like plant. Daylilies, switchgrass, liriope, sedges--these appear throughout the garden. It is a shape repeated. Having that shape repeated helps to tie the whole landscape together. However, this type of repetition is more about creating Unity than it is about "comfort," so the impact of a certain design Principle varies according to the manner in which you use it.

Let's get back to the group of three and consider the waltz. The waltz is a dance characterized by three/four time--three beats to a measure. One-Two-Three, One-Two-Three, One-Two-Three. This is a rhythm. Now to do this with plants, you can choose to execute it with groups of three plants, or with three groups of same size plantings. This first photo shows two (of an actual five) groups of three violas. Even though the violas in the two groups are of different colors, they are the same form, the same essential plant. They create an unconscious one-two-three, one-two-three, one-two three as we walk along. They are small, and the rhythm is subtle. Not all design has to smack you in the face.

My second example uses three groups of five violas, with the groups alternating from the left to the right side of the path, so that I am still being "led" up the path in anticipation of the next group. A larger group of violas (still an odd number, though) gives me the opportunity to use the group to frame a larger plant or plants behind them--in this case, daylilies. The daylilies will die back long before the violas do, but, in the meantime, they act as points of emphasis to add weight to the grouping of violas. This photo was taken on the day of planting.

Now. Please note that the line of violas is not straight. A straight line is not rhythmical or seductive. March-like, maybe. But a straight line would create simple repetition, without the lyrical dance of nature.

Obviously, both of these examples use more than a mere three plants. Violas are a very small plant, so planting them in masses is far more effective visually for both me and the insects and birds who will use them. With larger perennials, perhaps




, I would purchase and plant three specimens in order to establish a group that I want to expand into a "mass" that will hold its own against the shrubs in my landscape plan. Using three specimens helps to ensure that I make enough space for that particular mass. It also helps me grow a "mass" faster!

Finally, the purchase of three larger specimens allows me to use a "random" application of the Principle of Rhythm, in which I have the same species first in one place, then another and then a final third location--to lead me through the garden. Visually, all of the three specimens should be able to be seen from one location.  Three mums amongst your smaller plants in fall, for instance--placed far enough apart where you must move in order to appreciate each up close--serve as your dance partner as you progress through your garden... one, ..... two, ..... three.

Keeping Pollinators Happy

Keeping Pollinators Happy