A Garden-Lou visit to the new Oertli Family Hardy Plant Nursery with Derek Lyle
Imagine being a world-class botanical garden with staff collecting rare and endangered plants and seeds from all over the planet to conserve and protect them for future generations. Imagine that same garden with multiple annual displays that change seasonally at least three times a year. Then, throw in the need for 50,000 additional plants for your new, eagerly awaited front entrance.
Imagine having only 18 jam-packed greenhouses on one acre to accommodate all that. You’re probably thinking it can’t be done.
And you are right.
The Oertli Family Hardy Plant Nursery rests on 6+ acres in the Tower Grove South Neighborhood and is a high-tech Godsend for Missouri Botanical Garden. The new facility furthers the Garden’s mission for conservation and sustainable practices, along with the need to grow hardy and annual plants for the grounds of the 79-acre public botanical garden, still locally called Shaw’s Garden. Speaking of Henry, what would the founder, Henry Shaw, think of the new off-site facility that enables MBG to conserve rare and endangered plant species as well as grow plants for the Garden’s displays and permanent collection?
He would have to be impressed. Henry would be impressed not only with the capabilities of the new facility but also with the horticulturalist in charge of it all.
At the helm of both greenhouse sites is Derek Lyle, the Senior Nursery Manager who somehow manages all this production with a non-profit budget. Derek’s been in the greenhouse industry for 23 years, 15 of them at MBG. After becoming Greenhouse Manager in 2013 he became involved in the design and function of the new Oertli Family facility from the ground up.
Since the development of the residential area surrounding it, MBG has remained “land-locked” and unable to expand the main garden site. Any form of MBG expansion results in off-sites like the Bayer Center (formerly Monsanto Building) in 1998 and the Commerce Bank Center for Science Education.
The Oertli Family Nursery ball started rolling in 2012 with the generous donation of the old Ahner’s Greenhouses, formerly on Manchester Road. With the addition of a garden-wide capitol campaign, the work could begin on the site graciously donated by the Oertli family in 2017. The first task was clearing the 16 aging warehouses on the site. After some research, detective work, and 24 soil profiles, Derek discovered that the site had once been a landfill, making it the second-highest point in the area after the Arsenal Hospital site.
The next phase of construction started in 2020 on the building that will house the seed bank, a micro-propagation lab, headhouse, and staff areas. It is hoped that this phase of the building construction will be finished early spring of 2025. One more future phase of construction remains which includes furnishing the labs, equipment, and additional structures for traditional nursery production. Currently, staff have a temporary mobile office trailer that is only 8’x40’ with only one restroom onsite.
In addition to the sterile conditions and temperature and humidity controls essential for the seed bank and tissue-culture facilities, a quarantine room will be provided to ensure protection from pests, disease, and cross-pollination under the strict USDA guidelines.
The seed bank consists of not one but two walk-in freezers with insulated floors and backup generators in case one fails. At the cost of $600,000, 1.2 million dollars are invested in just two rooms, so grants (and donations) are key to the ongoing construction and operating costs. According to Derek, at the current rate seeds are obtained, it will take approximately 75 years before the bank is full.
The facility includes warm and cold/orthodox ‘grow rooms’ for seeds needing precise temperature stratification. (Orthodox means hardy, as in plants used to our local temperatures.)
Water is vital to the success of any greenhouse, and Derek reminds us that St. Louis water is bad for plants, with a pH of 9-10, compared to the 6.8-7 pH of rainwater. Future additions to the headhouse will include a reverse osmosis irrigation system to purify the domestic water supply, provide adequate water pressure, and more automation to the site’s irrigation needs. With additional funding, the hardy plant nursery site aims to harvest rainwater for repurposing during the process of plant production. Although some terra cotta pots are still used, heavy-duty plastic containers that can be sterilized and reused are the norm.
The greenhouses are gas heated. The high-efficiency system can heat up to 40 degrees within five minutes. The sawtooth design of the greenhouse roofline is better for heat and light compared to the traditional peaked style. Auto-shade cloth, which helps to control light, does double duty as a thermal blanket at night in winter. Everything is controlled and protected by an Argus Alarm System, and Derek will receive a phone alert if something goes wrong.
Sixty thousand plants for the new Jack C. Taylor Visitor Center entrance were grown here for two years Over 350 of those taxa were new species in the garden’s collection. The plant selection for the entrance pushed the boundaries by being a hybrid of Landscape Architects and MBG staff.
Five full-time positions were added to help run the new facility, and three more are still needed. Currently, 12 volunteers assist at the facility. With the new entrance fully planted, all the new plants for the new Museum Building area are waiting to be installed, some this fall and the rest next spring.
Outdoors, trees and shrubs destined for the main garden grounds line up like soldiers in neat, organized ranks. The designated area can hold up to 5000 trees lined pot-to-pot. Air pots ensure a more fibrous root system and guard against girdling roots. Derek notes a 20-30% faster growth rate with the air pots. However, every pot has pros and cons. The pots are expensive and labor-intensive, but the bottoms are adjustable and can be sterilized, stored, and reused.
Steel posts support cable lines are used to keep plant material upright at the windy site. The plants are attached to the cables with flexible Nit-Ize ties, a clever trick Derek came up with.
One large outdoor shade structure is in full operation, but two are hoped for eventually. In addition to glass greenhouses, hoop houses provide extra storage space for up to 40,000 plants.
Part of being a world-class botanical garden is keeping records-of everything. Staff spend 30% of their time devoted to data, using I-Pads or Chromebooks to enter everything from initial accessioning when a plant arrives to tracking its location, division, removal, and death. About 3000 new plants are accessioned every year at MBG.
The new nursery and the collected plants within enable Derek and the staff to conduct experiments with multiple plants of the same species but from different locations. They observe how each plant performs and record the data, which can be analyzed. Data like this sets apart a botanical garden from being ‘just a pretty face’ to a research-driven scientific organization. The Oertli Family Hardy Plant Nursery enables MBG to further our understanding of the plant world and ensure its protection and survival, and therefore ours.
Special thanks to The Garden Conservancy for arranging this tour! Click here to learn more;
For more information about Missouri Botanical Garden, visit;
Comments or questions? Email Garden-Lou at gardenloustl@gmail.com
Words and photos by Jo Batzer
© Jo Batzer, garden-lou.com-2024, All rights reserved.
