We continue our survey of online resources for gardeners. We have recently considered solutions to garden problems, plant identification, and plant selection in recent columns. In today’s column, we explore online resources for landscaping.

Today’s photo gallery features plants observed at a recent garden party hosted by a Monterey Bay Iris Society member. These photos include tall bearded irises because right now is the peak bloom season for these fascinating plants.

In addition to noting the irises’ peak bloom period, we call attention to the Annual Iris Show presented by our friends in the Monterey Bay Iris Society. This event displays selected blossoms grown by Iris Society members as an opportunity for gardeners to see plants they would like to add to their landscapes. The society will present its Annual Iris Show at the London Nelson Community Center, 301 Center St., Santa Cruz. The event schedule includes 1-6 p.m. Saturday and 10 a.m. to 5 p.m. Sunday.

Take notes at this event and mark your calendar to attend the Monterey Bay Iris Society’s rhizome sale, which will occur in Deer Park Shopping Center on the first Saturday in August, and at the Cabrillo farmers market, on the second and third Saturdays in August.

Our additional motivation for including photos from a garden party is to favor gardening as an in-person activity, even as we discuss computer-based information.

Let’s proceed to today’s topic: online resources for landscaping.

Landscape planning is based on the garden’s particular size, shape and environment, and the gardener’s experiences, preferences and purposes.

Given these many variables, landscaping can be a challenging task.

One way to start would be to select a garden style. Wikipedia provides a mind-boggling online list of garden styles: search wikipedia.com for “garden design.”

Developing a preferred style for your garden will require plant selection and acquisition, which could involve considerable time. While online resources related to each garden style could be found, references to such resources are well beyond the scope of this column.

Matrix gardening

For this column, we will recommend a landscaping model called matrix planting. This model is based on the natural environment, in which wildflowers grow successfully without human assistance. Nature establishes self-sustaining plant communities that grow with one another in a balanced environment: all survive and flourish, and weeds are excluded.

The matrix planting model might be referred to with other terms, including complex succession matrix, an organizing strategy, naturalistic garden, self-sustaining garden, etc. The term “matrix” is used in various ways, but its basic meaning applies well to landscaping: an environment or material in which something develops; a surrounding medium or structure.

The plants of the matrix

A matrix planting consists of three levels (or layers) of plants:

• Ground layer plants provide the foundation or background for the other layers. This layer involves ground cover plants and could include sedges and ornamental grasses. These plants have relatively short roots that shade the soil, provide wildlife habitat, and discourage weeds. This layer could comprise up to 50% of the landscaped area.

• Seasonal flowers are placed in clumps or drifts, providing seasonal displays of color. These are forbs, i.e., herbaceous flowering plants other than grass. Plants of similar height provide a softer view, while a mix that includes some taller plants would mimic nature more closely. These plants could comprise up to another 50% of the area.

• Structural plants, including larger perennial forbs, shrubs or trees, add an artistic layer to the garden by framing a viewing, serving as focal points, guiding visitors down a path, etc.Selecting plants for each of these categories of plants includes site considerations, plant compatibilities, blossom colors, bloom seasons, plant availabilities, etc., so this research could take time.

Emphasizing California native plants is an option for developing a matrix planting. While exotic plants could be used in such a landscape, a garden based on local California native plants will tolerate drought, support wildlife and enhance a naturalistic style.

The California Native Plant Society’s Calscape Garden Planner (gardenplanner.calscape.org) is a practical resource for selecting and sourcing California native plants for a matrix model planting.

After the gardener responds to the garden planner’s four basic criteria, Calscape will produce lists of trees, shrubs and perennial herbs that would be suitable for a matrix planting for the area described. Each plant listed includes extensive information, e.g., cultivation needs, companion plants, and nursery availability.

The planner’s lists might include ground cover plants, but a separate search of the Calscape database could be helpful. Browse to calscape.org and click on “explore native plants.” This opens a page for selecting plants by name that are appropriate for the searcher’s city or ZIP code.

For example, my search for the genus Carex for ZIP 95060 produced a list of 155 species. After filtering my search for plants that are 1-2 feet high and 1-2 feet wide. Calscape produced one option, Carex nudata, described as follows.

“Carex nudata is a species in the Cyperaceae (Sedge) family known by several common names, including Torrent Sedge, California Black-flowering Sedge, Dudley’s Sedge, and Naked Sedge. This is a bright green sedge which grows in mounds below the high-water mark in marshes and on river banks. It bears long scaly spikes of black, dark reddish or dusky brown flowers, which begin erect and then droop when they become heavy. It grows amidst rocks and becomes a dense mounding tussock. It is found mainly in California and Oregon.”

The search indicated that this plant was available from nine nurseries.

Selecting plants for a matrix planting based on California native plants will take some time and effort, but the result could be self-sustaining and satisfying for the discerning gardener. A matrix planting could be developed slowly and could be based on small plants to limit purchase costs. Once established, the planting could benefit from occasional “tweaking,” so it should be treated as a continuing project, rather than a fixed product.

Advancing your knowledge

A Google search of the internet for “matrix planting” will lead to several links that are worth reading. The noted garden designer, Piet Oudolf, has popularized the matrix planting model, so a search for his name will provide links regarding his ideas and work.

An inexpensive book, “A Brief Guide to Matrix GardenDesign,” by Monarch Gardens, is available from www.etsy.com (search for the title).

An early and larger book by Peter Thompson, “The Self-Sustaining Garden: The Guide to Matrix Planting” (2007) is available from Amazon.com.

In future columns, we’ll review online resources for ideas/approaches to garden design, and plant cultivation practices.

Consider matrix planting and enjoy your garden!

Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society, and a Lifetime UC Master Gardener (Certified 1999-2009). He is now a board member of the Santa Cruz Hostel Society, and active with the Pacific Horticultural Society. To view photos from his garden, https://www.facebook.com/ongardeningcom- 566511763375123/ . For garden coaching info and an archive of On Gardening columns, visit ongardening.com for earlier columns or visit www.santacruzsentinel.com/ and search for “Karwin” for more recent columns. Email comments or questions to gardening@karwin.com.