Locating garden plants
We now continue the seasonal emphasis on garden development, considering the timely installation of new plants as we enter the rainy season (after a long wait).
The basics of garden development are plant selection and plant placement. Let’s focus on placement.
Spacing
An overview perspective concerns spacing. Some gardeners prefer retaining spaces between plants, allowing each plant to display its unique qualities. This approach can be effective especially with a collection of cultivars within a single genus, e.g., a bed of roses, designed to feature differences between the individual plants. The spaces between plants might be filled with mulch or a low groundcover, to limit weed growth.
Alternatively, providing just enough room for each plant to achieve its mature width can provide an aesthetically satisfactory design and effective weed control. Close spacing requires more plants per square foot than open spacing. It also requires learning each plant’s eventual size and waiting patiently for its growth to achieve the intended design.
An open spacing error could occur when the gardener attempts to limit expenses by “filling” an area with a limited number of plants that will not grow large enough for a good effect. A better approach to plant seeds or starts of annual flowering plants to complement smaller perennials or shrubs while they grow.
Natural grouping
Another important aspect of plant placement involves the relationships between plants.
Natural grouping of plants includes colonies and companions. Plants form colonies by propagating themselves by dropping seeds; spreading stolons; creating offsets; and increasing bulbs, rhizomes, tubers, etc. Plant colonies are typically closely grouped near the parent, but when seeds are dispersed by wind, birds, or animals, the results could be widespread or isolated plants.
Companion plants in na
ture are simply those that develop near each other within a given habitat, which could be forest, woodland, grassland, or desert. The larger concept, a biotic community, is a group of plants and other organisms that live together and interact with each other within an environment or habitat. For the record, the even larger concept, which includes the physical environment, is an ecosystem.
Ecological design of your garden (a topic too large for this column) includes consideration of wildlife as well as your plants.
The gardener could closely group plants using natural guidelines by clustering several specimens of a selected plant. The usual practice is to form groups of odd numbers of plants: three, five, seven, etc.
To simulate naturally occurring wide spacing of plants, the gardener could install drifts or repetitions of a selected plant. Repetitive placements should be near enough to each other to suggest Nature’s dispersal of plants.
Following Nature’s companion planting model could require the gardener to study the chosen habitat, as plant hunters do, as we can observe in some webinars. (Last week’s webinar, with Kelly Griffin’s “Oaxaca Meanderings in Search of Succulents,” was an example.)
An easier approach is to dive into the literature of the chosen habitat. An available strategy for California native plants is to visit the California Native Plant Society’s website: calscape.org, which provides the Calscape Garden Planner to help find “plants unique to your ZIP code and design ideas for a range of landscaping styles.” Remember that habitats include microclimates, so all plants growing within a given ZIP code are not necessarily natural companions.
Aesthetic grouping
Instead of following Nature’s guidelines, the gardener could place plants in ways that provide aesthetic pleasure, or at least interest. The primary variables include plant size, leaf form and color, and blossom color.
Plant size groupings generally follow the basic “larger plants in back” rule, but exceptions can use of open-structured plants, e.g., in the foreground. To learn about such grouping, visit www.finegardening.com/article/episode69-seethrough-plants.
When grouping plants by leaf form, the usual practice is to include contrasting forms or colors. While grouping plants with similar leaf forms or colors might be pleasing, it’s difficult to envision three redleafed trees in a group. It can be attractive, however, to combine dwarf evergreen shrubs that have similar needles but different shades of green.
Plant groupings based on blossom color could emphasize a single color, e.g., the famous white garden
of Sissinghurst Castle, or use the color wheel to form analogous, complimentary, triadic, or tetradic color combinations.
Many plants can be grouped aesthetically to good effect. The design’s success will depend on the beholder, so pursue your vision. Still, while we never say never, and a bold design could be a worthy experiment, grouping plants from disparate habitats could disappoint. Matching a rose and a cactus, for example, might not win a design competition.
Enrich your gardening days
A good project in your garden would be to assess current plant locations, or to plan new groups in a developing garden. If you determine that some existing plants could be grouped differently for better effect, the current season is a good time to rearrange plants or to add plants to create a pleasing display.
Enjoy your garden!