Mapping the Garden

The Garden is thriving, thanks in no small part to the role and importance of plant curation.

Rancho Santa Ana Botanic Garden is a museum of plants—a living collection. The Garden’s curated living collection contains more than 22,000 plants, representing nearly 1,400 species, hybrids and cultivars of native California flora.

To effectively take care of this vast collection, an accession system is vital to the overall wellbeing of the Garden. Plant curation, like art curation, involves the meaningful organization of information about a collection.

As curator of the living collection, Shawn Overstreet was responsible for the management of RSABG’s records of each plant growing in the Garden. He recently left his post in order to pursue doctoral studies in horticulture and agronomy (agronomy is the science and technology of agriculture) at the University of California, Davis. But not before helping RSABG reach a milestone achievement—mapping 95 percent of the plants on the Garden’s 86 acres.

Each plant at the Garden is tagged with a unique accession number. That identification number along with the location, size, species, condition, care requirements and disease concerns for each plant is recorded and used to create a living collection map.

“The real joy of curating a collection is assembling and arranging plants in a way that tells a story about California flora,” says Overstreet.

As of three years ago, 75 percent of the Garden’s plants had joined that chronicle. That left approximately 3,000 plants that had not been mapped and inventoried, most of which had been planted at least a decade ago. By August 2011, Overstreet, along with a band of four volunteers and an intern, had whittled that number down to 600.

Throughout the hot days of late summer, the group, armed with maps and plant lists, played detectives—peering into every corner of the Garden.

The weekly expeditions, called field checks, tracked down the plants using fixed monuments.

The round brass markers are small and close to the ground but are easy to locate because they are installed on a surveyed 100-foot grid that spans the Garden. These field checks identify the uncurated plants that are still present. As each plant is found, the information is recorded and the legacy plantings that no longer exist are removed from BG-Base, the collection management software that drives RSABG’s curation database.

Once recorded, the information is powerful. It can be used to understand the big picture of the Garden’s ecosystems. It provides a guide for RSABG horticulturists about what should be in each area. A well-groomed database enables visiting researchers and RSABG scientists to find what they are looking for. In addition to providing stunning displays for visitors, plants at the Garden provide scientists from all over the world with information and material for research projects. And it facilitates informed decisions about new plant selections and locations.

Overstreet, who focused on threatened and endangered taxa during his four-and-a-half-year tenure, sought to continue to diversify the collection and add underrepresented plant families. In 2007, the American Fern Society asked what ferns were in the Garden. The answer was “not many.”

“I went through BG-Base and looked at the distribution of plants at the family level and looked at the fern families to see how many plants we had,” says Overstreet.

That query and subsequent research helped identify the need and bring a larger contingency of ferns into the collection. Several new fern taxa were introduced as a result including Sonoran maiden fern (Thelypteris puberula var. sonorensis) and several species of lip ferns (Cheilanthes).

This fall as part of his doctoral studies, Overstreet is researching the possibility of reducing global warming by replacing some of the 90 million acres of corn grown in the U.S. annually with large tracts of oak forest that would help to remove greenhouse gases from the atmosphere. Acorn crops have the potential to be substituted for the corn currently used for food, animal feed and industrial purposes.

RSABG recently hired Helen Smisko as Overstreet’s successor. As the plant records manager, Smisko will pick up where Overstreet left off. A retired software engineer, she has geographical information systems and horticultural certifications under her belt. And as a RSABG volunteer, Smisko worked directly with Overstreet mapping the Garden for the last nine months.