Plants – especially the ones chosen for their showy splendor and horticultural prowess – are amazing and beautiful creatures; they come in all sizes, shapes and colors. How are we to begin combining them in the garden so they all look good without getting lost in the jumble? A garden designer myself, I am unable to give you any exact formula – as far as I know none exists – but I can give you some ideas and guidelines.
Massing
First off, whatever it is, almost without exception mass it. Group a number of the species at hand together for more dramatic effect. The results will elicit more satisfaction on your part and oohs and ahhs on the parts of your neighbors and friends. Onesies and twosies too easily get lost in the shuffle and create what I think of as a circus in the garden. Any feeling of calmness or serenity you might be after is lost.
But wait, don’t group just any number! Plants must be grouped in odd numbers. Ask anyone who deals in design endeavors and they will tell you it’s the same in their field as well. Apparently the eye plays a trick of involuntarily dividing any even number grouping in half resulting in a garden that appears broken up and less cohesive. Now this is in regards to most home gardens where you are thinking of planting three, five, seven, even eleven of some plant. But if you are planting a groundcover for a large area, I say forget trying to make sure you have 43 instead of 42 of them.
Notice that massing is how nature tends to do it. You’ll see a sizeable grouping of lupine on the hillside here…and there…and there. It is lovely, and noticeable at a distance. One or two are lost to the eye until you are right upon them. That Mother Nature sure was thinking when she planned what would be most striking to us humans!
It’s acceptable to plant one of something in the case of specimens, but generally speaking those are shrubs or trees and outside the scope of this article.
Conquering the Green Blur
The green blur is what happens when all the plants look the same – nothing stands out; there is no distinction. Even when many different plants are present, without proper planning a blur can result. This is boring! Instead, when planning your perennial beds arrange your masses of dissimilar plants adjacent to one another.
The Richness of Contrast
Form
Take a step or two back and think about the form of the plant. This step will help you look at your garden more from the eyes of a designer than those of a horticulturist. Both are ultimately important for a successful and dazzling garden, but to first look at form and decide what size, shape, and habit of plant would look good in the space you have will make it easier to narrow down the myriad options to then plug in a good horticultural fit.
The basic forms you’ll encounter follow along with an example of each:
Mound – Geranium sp./Perennial geranium
Mat – Delosperma sp./Ice plant
Upright – ornamental grasses
Vase – Linum lewisii/Blue flax
Upright clump – Agastache rupetris/Sunset hyssop
And then there are endless combinations of the above.
Flower form can also be broken down into categories that can then be mixed and matched.
Umbel – Achillea sp./Yarrow
Composite (daisy-like) – Gazania linearis ‘Colorado Gold’/Colorado gold African daisy (any sunflower or daisy)
Spike – Liatris punctata/Gay feather
Funnel form – Mirabilis multiflora/Desert 4 o’clock
Bilateral (snapdragon or pea-like) – Penstemon palmeri/Palmer’s penstemon
Foliage
One method employed by some designers is to design for foliage alone. Using this approach when combining plants can help you think about your plant selections in a very different way. Pretend your plants didn’t flower and make them look great together by selecting different shades of green and contrasting leaf shape, size, and texture. Then the flowers become a bonus and you are more likely to be delighted by your plants throughout the season as opposed to only during blooming which can seem far too brief.
Here in zone 4 we have so many cool silvery, grey, and glaucous (blue-green) leaved perennials – Antennaria rosea/Pussytoes, Chrysothamnus nauseousus/Chamisa, Artemisia ‘Seafoam’/Seafoam artemisa, Eriogonum umbellatum/Sulfur flower – that can be used elegantly in the garden to help enunciate the differences between plants and help to eradicate the “green blur”. And more are showing up all the time, like Oenothera macrocarpa ssp. incana ‘Silverblade’, for example. Try pairing this beauty with Callirhoe involucrata/Winecups and Plant Select’s new introduction Bouteloua gracilis ‘Blonde Ambition’ for a smashing, long blooming combo. Each of these plants has a growth form and leaf shape, color, and texture that stands out as very distinct from the others in the triad.
Texture
Let’s talk more about texture for a moment. Try thinking about your plants in terms of texture. The ornamental Verbascum/Mulleins offer what’s considered a coarse texture, as do the Papaver orientale/Oriental poppies. Fine textured plants, on the opposite end of the spectrum would be Coreopsis verticillata ‘Zagreb’/Zagreb tickseed, Erodium petraeum/Storksbill, Penstemon pinifolius/Pine leaf penstemon and Linum lewisii/Blue flax. Medium textured plants, as you might imagine fall between the above categories and include plants like Penstemon strictus/Rocky Mountain penstemon.
Color
Some people desire a monochromatic garden where they combine varying shades of one hue to result in a certain effect. Purples, for example tend to have a soothing quality appropriate for meditation gardens. Such cool colors recede, appearing farther away than they really are. Reds and oranges on the other hand are active warm colors and tend to appear closer.
Keeping these ideas in mind can be helpful when planning a garden where many colors are combined. This is my kind of garden, and I’ll take the jewel tones, please; one reason I so love the ice plants boasting the shiny in-your-face magenta, and no apologies deep yellow (if there can be such a thing as deep yellow it certainly exists in the Delosperma genus). I know, most Delospermas are rated hardy only to zone 5, but Delosperma congestum and D. nubiginum, the yellow ones, are rated to zone 4, not to mention I’ve seen ice plants grown successfully in Calgary, considered zone 3. So take advantage of your microclimates and take zone designation with a grain of salt.
A lot of strategy can go into combining colors in a perennial garden bed; meanwhile so many people are wooed by the cottage garden look where all colors are combined and trusted to look beautiful in the end. Some gardeners of this mind take the approach that no colors clash in the garden; they all just serve to enhance, compliment, and contrast one another gracefully. If you are not of this mind, there is much reading you can do on color combining. I personally prefer bold contrasts to create dramatic distinction in my garden.
Placement
I know the traditional method of garden plant design has the lowest growing (mats, and low mounds) in the front gradually working up to the tallest plants in the back; the stadium seating method. Well, while this method can make sense, it isn’t always the most interesting from a design sense. It can be exciting to mix it up bit and have to look around, or behind, or change your angle. It’s just not as fun when everything is exposed at once. So, I encourage you to dare to place a grouping of upright vase shaped Blue flax in front of your low mounding Ozark sundrops now and then and see what you think. Remember too, that the brilliant yellow of the sundrops is going to come forward, seeming to draw closer while the cool blue flax appears to draw back. Experiment. Have fun. The nice thing about plants – as I’m sure many of you well know from much experience – is that you can always move them if you don’t like where you first planted them.
Getting Started
Start with what’s easy. Perhaps you have a utility box or post you’d rather not see; plants with verticality (upright form) would be natural selections for that spot – Andropogon gerardii/Big blue stem, a nice tall native grass let’s say. Then build around it. A lower growing plant with a long bloom season that would be set off by the grass would sure be nice – spreading mound Mirabilis multiflora/Desert 4 o’clock with its medium/coarse texture and long blooming purply-magenta flowers. What would contrast both of those in flower and maybe foliage color as well as offering a totally different growth habit in size, shape and color? How about the yellow fading to red flowered, mat forming Eriogonum umbellatum ‘Kannah Creek’? Yes! Perfect. And these all happen to be extremely low water requiring plants, as in the easiest way to kill them is to give them too much water. When in doubt don’t water this dynamic trio.
Mirabilis, in the above example, may be an exception to the rule of massing. This plant is one of my all time favorites for our climate here in Western zone 4 (and warmer) and it gets huge. If you have a small space you might get away with just one of these puppies. And as for ornamental grasses in the garden, you might want to view them as “bones” defined as a feature that is carried throughout the garden for unity and cohesion. In this case they may be best used as accents rather than massed, but still an odd number when all is said and done.
Winning Combinations
Guilds, or groupings, of three plants that share cultural needs like sun exposure and water requirements can be a helpful way to start your plan. Following are some of my favorites for a sunny situation in zone 4.
Yucca filamentosa/Adam’s needle
Delosperma cooperi ‘Table Mountain’/Table Mountain ice plant (rated zone 4 by some, zone 5 by others)
Anchusa azurea/Alkanet
Echium amoenum/Red feathers
Helianthus maximiliana/Maxmilian sunflower
Penstemon linarioides/Blue mat penstemon
Penstemon strictus/Rocky Mountain penstemon
Oenothera macrocarpa/Ozark sundrops
Schizachyrium scoparium/Little blue stem grass
Eriogonum umbellatum ‘Kannah Creek’/Kannah Creek buckwheat
Callirhoe involucrata/Winecups
Kniphofia uvaria ‘Hybrid Mix’/Red hot poker
Penstemon palmeri/Palmer’s penstemon
Oenothera caespitosa/Tufted evening primrose
Zinnia grandiflora/Prairie zinnia
*Beware, this is another guild that can very easily be watered to death. Remember, with well adapted plants water does not equal love!
Linum lewisii/Blue flax
Calylophus serrulatus/Dwarf sundrops
Asclepias tuberosa/Butterfly weed
I relish using plants that fit; fit our climate, our soils, our busy active lifestyles. I love to garden, but I also love doing other things with my time and energy. Options are nice and you, as a gardener, have more when you aren’t a slave to your garden. As a result, I want you to know that all the plants I’ve mentioned are ones I have found to be good fits according to the above criteria. They are considered xeric and low maintenance. Many of them are native and Plant Select plants (plantselelct.org) and may not yet be found in every nursery in our zone. However, an increased demand for more choices of appropriate plants will give the nurseries and garden centers incentive to start carrying more diverse and fitting selections.
While I wholeheartedly support shopping local to encourage healthy local economies, I also have great appreciation for the efforts of High Country Gardens in introducing and popularizing a diverse array of appropriate plants to our bioregion. Loads of great information can be found on their website, highcountrygardens.com.
Happy planning and planting!
