Employees Lead U.S. Botanic Garden Horticultural Renovations

While the USBG Conservatory has been closed during the pandemic, many employees have helped offer online programming to engage the public and several employees stepped up to lead improvement projects inside the Conservatory. The Tropics, Primeval Garden and Orchids houses all received additional attention from members of the Horticulture team. The goals underlying each of the three projects were to improve the growing spaces and to showcase more of the USBG's permanent plant collection.

The USBG living plant collection is the foundation of the institution. Maintaining an ordered, documented, labeled collection of plants is essential to the USBG's mission of promoting botanical knowledge. The USBG maintains approximately 12,000 permanent accessions that are used for exhibition, study and exchange with other institutions. The Conservatory houses showcase different groupings of plants. Some are organized by native habitat, like World Deserts and the Tropics, while others are grouped by theme, such as Medicinal Plants and Orchids. Four USBG Horticulture employees made critical contributions to improving growing conditions and plant displays over the past year to better showcase the USBG collection.

Primeval Garden

Gardener Santos Carrillo has cared for the Primeval Garden room for most of the past decade. This area showcases plants descended from those that grew during the time of the dinosaurs, particularly in the Jurassic period. Carrillo had noticed that one of the planting bed holding walls had started to decline over the last few years, reducing the width of the pedestrian pathway and providing less-than-optimal growing spaces for plants in that area.

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Gardener Santos Carrillo secures a new plant into place in the renovated Primeval Garden retaining wall.

Carrillo developed a plan in consultation with others at the USBG, and began with gusto, removing all the rocks in the holding wall, cleaning them and then building the wall anew. Carrillo added larger rocks to build a more secure structure that would function as a retaining wall. He used a special binder that would hold the rocks together and allow plants to grow on them. The older wall had been made of smaller rocks that could more easily move over time and was bound together by a material that impeded plant growth.

Carrillo created spaces for approximately 25 additional plants in the new wall and planting areas. He also made the pedestrian pathway wider and more accessible in the process, making it easier for pedestrians to move through with strollers and wheelchairs, and for visitors to pass each other as they walk through the house. New cycads and ferns from the USBG permanent collection were added to the room, with the cycad Macrozamia moorei being Carrillo's favorite new plant, because it currently looks like a pineapple.

"I am very happy to accomplish this project for the agency," said Carrillo. "It was a project that needed to get done, and I was proud to take the lead to get it completed."

The Tropics

The 93-feet-tall Tropics house features plants from tropical forests around the world and is the largest greenhouse in the Conservatory. Stephen Jones and Dr. Benjamin Gutman, who both care for USBG tropical plants, collaborated on two renovation projects that brought new life to the Tropics house.

In November 2019, the Horticulture team inventoried every plant in the Tropics house, with the goal of better following the USBG collections policy by removing plants that were not part of the permanent, accessioned collection. A number of noncollection plants were identified that had accumulated from previous exhibits and displays. Three beds in the southern part of the house were mostly housing noncollection plants and the soil needed a renovation.

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Arborist Stephen Jones and Gardener Benjamin Gutman, who led the renovations in the Tropics house.

Jones and Gutman removed all the noncollection plants and excavated several feet of the old, depleted soil. They built new soil that will function in the space for many years. When the team discussed what plants to feature there instead, a large torch ginger from the collection was already in the bed and served as an inspiration. Gutman scoured the USBG's tropical plant collection and landed on a display of more than a dozen species from that same ginger family (Zingerberaceae).

"I wanted to display the great diversity of the ginger family," said Gutman. "The new plants show distinct shapes, sizes and colors of leaves plus different flowers and flowering times." The new plants range in size from a ground cover species that is only 6 inches tall to others that will grow to 6 or 7 feet.

For the other plants in the area, the duo prioritized showcasing tropical plants in the USBG collection not already represented in the room. A key consideration was the location of the beds and their small size. They are in a high-traffic area with doors heading to the World Deserts and Medicinal Plants houses on either side of the beds, so they wanted to choose plants that would have interesting blooms or foliage at eye level.

Gutman said Nesocodon mauritianus is a particular favorite among the new plants. The purple bell-shaped flowers have red nectar — an unusual color for nectar. In its native Mauritius, the red color attracts geckos, which serve as pollinators. It grows on rocks and cliffs, so they added rocks into the display to grow this plant, as well as some other tropical orchids and begonias that grow on rocks.

This new dark-leafed orchid being planted by Gardener Benjamin Gutman is one of more than 40 new species of plants added into the Tropics house; The plants of the Tropics house benefit from increased humidity generated by a newly installed fogger system.

"We're always looking for new ways to display our collection for the public," said Jones. "There are a finite number of places inside the Conservatory to display plants, so it was great to be able to reassess a particular space and find new ways to creatively display more of our collection plants."

The pair also renovated a separate bed with an overgrown tulip tree, which had become a maintenance concern, requiring pruning as often as once a month with lots of intricate climbing work. They decided to cut most of the tree down and use the stump and log as planting spaces for smaller epiphytic plants ranging from spike mosses to a hanging cactus. This replicated a scene from a tropical forest where the tree might have been broken in a storm. In total between both projects, the two installed more than 40 new plant species in the Tropics house.

As a third improvement, Jones collaborated with the Operations team to install a new series of foggers at the very top of the Tropics house, to keep temperature and humidity at higher, more consistent levels. Humidity had previously been dropping when cooling had been needed in summer months. Jones and fellow Arborist Shaun Abell used their specialized climbing expertise to work at the top of the house in coordination with Operations team members working on the high catwalk. The new fogging system is successfully moderating temperatures and humidity.

Orchids

USBG Orchid Gardener Dr. Benjamin Crain saw several challenges in the Orchids house that were not supporting optimal orchid collection display. He led renovations to rebuild several stone walls and hardscaping, transform the waterfall that had stopped functioning into a new seeping wall and overhaul the soil.

The project made the house safer, improving stability of the hardscape elements that the employees use for moving through the planting beds. Excess roots from the central ficus tree were removed, and the walls and rocks surrounding the pond and beds were rebuilt to be more solid, while also delineating separate planting areas. Debris was removed and the pockets in the wall were custom shaped to better hold the orchid pots for stability and to keep them raised above the rocks to receive more light.

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The Orchid house renovations made the house safer as well as improved planting areas for the terrestrial orchids through removal of excess roots from the ficus tree and refurbishment of the ground-level planting area with new, healthy soil.

The new seeping wall now has water flowing down the rock face, which will raise the humidity to the benefit of the orchids. Crain added new permanent ferns and moss as a living, green background for the orchids that will hang in that area of the room.

Crain replaced the deteriorated, debris-filled soil with new, healthy soil; planted multiple species of terrestrial orchids in the new soil; and attached some epiphytic orchids onto the ficus tree.

The Orchids house had never had any orchids permanently planted in the soil in the room. The new permanent plantings feature beautiful foliage in addition to their blooms and were strategically placed to hide functional elements.

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Orchid Gardener Benjamin Crain pauses for a photo in front of a wall he renovated in the Orchids house.

"I feel there is now a clean, solid slate for the Orchids house," said Crain. "It is safe and will better allow us to display the many orchids in the USBG collection."

Triple Wins

"These employees are experts on the plants they grow in their areas," said Jim Adams, Horticulture Manager. "Being closed to the public has been hard on the employees who enjoy sharing the plants they care for, but we've tried to use this time as an opportunity to safely increase our collections on display and visitor access.

"Projects like these also give employees a chance to be creative. It's been great to see them using their knowledge and inspiration, while working with others in the Horticulture and Operations teams to map out the best path forward for the Garden."

These employee-led improvements are a triple win, generating improvements in safety, access and display for USBG visitors and employees while also benefiting the USBG's plant collection.