2018 Saratoga Horticultural Research Endowment Proposal The Ruth Bancroft Garden- Aloe Hybrid Breeding Project Aloe Hybrid Breeding Project for California and Tissue Culture Production of Selected Plants for Sale Proposal Total Budget: $ 25,415 - $39, 415; Requested Amount: $ 25,000 Applicant Organization: The Ruth Bancroft Garden 1552 Bancroft Road, Walnut Creek, CA 94598 Location of Project: The Ruth Bancroft Garden, (hereinafter TRBG), address above Co-Principal Investigators and Project Managers: Brian Kemble, Curator, The Ruth Bancroft Garden Walker Young, Assistant Curator, The Ruth Bancroft Garden (925) 944-9352 The Ruth Bancroft Garden office; [email protected] Consultants: Randy Baldwin, Owner-San Marcos Growers; [email protected] Ernesto Sandoval, Curator-Botanical Conservatory, UC Davis; [email protected] Executive Summary This project seeks to develop new aloe hybrids to encourage the transition to more water-conserving garden plants and to expand the range of climate-appropriate plants available for California gardens. We propose to take five aloe hybrids created by Brian Kemble over the last 35 years, and test them in three microclimates at TRBG for a year. These hybrids differ from the bulk of recent introductions. Many fine aloe hybrids have come out of South Africa in recent years, but these come from the summer rainfall region, and focus on flowers alone. Aloes from southern California have focused on miniatures with unusual leaves. This project focuses on landscape-worthy hybrids suited for California’s Mediterranean climate. Data collected will be used to determine how well the hybrids perform. Results will be used to put the top performers into tissue culture for introduction into commercial use. Hybrids under study will be noted with signage for the public, and desirable features highlighted in an accompanying brochure and on TRBG website. Results will be reported to horticultural experts through the website and in three horticultural journals. This project will result in up to 5 new striking, desirable, and hardy aloes available for California landscape use. Does this project address one or more of the five identified research and education priorities of the SHRE? This aloe hybrid project encompasses Priority 2: It encourages the transition to more water-conserving plant species for ornamental use, since aloes are succulents and require little water, and their foliage and flowers are outstanding for their durability and dramatic presence in the landscape. 1 2018 Saratoga Horticultural Research Endowment Proposal The Ruth Bancroft Garden- Aloe Hybrid Breeding Project This aloe hybrid project also encompasses Priority 3: It will expand the range of available climate- appropriate plants for California by creating new aloes that have been proven to be well suited to California’s dry regions and which will be produced in commercial quantities and thereby increase the menu of aloes available for landscape use. Needs and Outcomes Need 1: Developing new aloe hybrids is important to expand the landscape choices available in terms of flower color, leaf color, texture, and flowering season. Moreover, this project will focus on mid-sized aloes, which are underrepresented among aloe hybrids currently in the trade. Outcome 1: This project will encourage the introduction of 5 mid-sized aloe hybrids into California horticulture. Each hybrid meets the low water requirements which are suitable for this dry region of California. In addition, each hybrid was bred for the following desirable characteristics: attractiveness of flowers and foliage, repeat flowering, ease of care, climatic tolerance, pest resistance and tolerance for winter or summer rainfall. The hybrids will be tested and the hardiest specimens put into tissue culture for mass production during the next 4 years. Need 2: Visitors to TRBG are constantly inquiring about whether they can purchase the aloe hybrids they see at the Garden, but the staff at TRBG have not found the support needed to make the specimens commercially available. Outcome 2: The project will help the TRBG discover which hybrids are most robust and worthy of broad introduction into the horticulture world, as well as determine which of the aloe hybrids would best become specialty items better suited to container gardening. This will be done by pushing the limits of the plants’ cold tolerance, their need for irrigation in the summer, and their tolerance of excessive rain in the winter, success in sun or shade, as well as tolerance for nutrient poor soils. Need 3: There is a need to promote general planting of ornamentals that are low water use plants in California, and aloes are low water use plants that are highly attractive to gardeners for a variety of reasons, especially their soft rosette structure and colorful foliage. Outcome 3: This project will promote to the public which aloes are being tested in the Garden with signage, on the website, and with an informational brochure on the hybrids and the many landscape advantages of aloes in California gardens, including low water use, leaf and flower beauty, and attractors of wildlife such as hummingbirds. Articles reporting on the year of climate trial at TRBG will also help publicize the new hybrids and their advantages. Need 4: There is a need for more landscape succulents that can tolerate California climates other than the milder coastal zones. 2 2018 Saratoga Horticultural Research Endowment Proposal The Ruth Bancroft Garden- Aloe Hybrid Breeding Project Outcome 4: This project will put into mass production via tissue culture an assortment of versatile new aloe hybrids suitable for inland California microclimates. Specifically, the hybrids will be tested in microclimates which experience temperatures down to the mid-twenties Fahrenheit, along with temperatures in the summer which frequently reach 100 degrees F. Main project narrative: Introduction There have been long-term drought conditions in California and the western states for much of the last 17 years. “Research indicates the current drought in the American West has been made worse by climate change and that future droughts will be exacerbated by the warming planet.” (Alistair Bland, 2016 “California’s Disappearing Dream” Earth Island Journal). We also know that by 2050 there will be 50 million people in California vying for water resources. The combination of diminishing resource and increasing users is a cause for concern. Dry-loving succulent plants address this concern by lowering the amount of irrigation required for attractive gardens. In addition to a 50 year history of experimentation with drought tolerant plants, TRBG is significant in that it lies in an interior climate zone approaching the northern limit for most commonly available succulents. This challenging set of conditions makes the Bancroft Garden an ideal laboratory for this experimentation. Aloe is one of the most popular succulent genera for its ecological low water use in general, for its beauty as an ornamental, and for its ease of propagation and care, and tangentially, for its significant medicinal properties. This project recognizes the need to develop and promote aloe cultivars which will be ever more attractive, water conserving, and hardy for ornamental use in California’s warming future. Aloes hybrids are sought after to provide color during winter when few other plants are flowering. In addition to their wonderful flowers, their sculptural rosettes come in myriad sizes, shapes, colors and textures. Two other desirable aloe characteristics are that the blooming period for one flower is usually quite lengthy, and aloes are great hummingbird pollinator attractors. The most commonly available hybrids in the trade have been produced in South Africa and southern California. In South Africa hybrids have been crossed to produce dramatic flowers. In southern California hybrids have been crossed mainly for green house environments to produce showy leaf patterns. Aloe hybrids with appeal on both of these fronts are less common. For 35 years, Brian Kemble has been breeding aloes with the goal of bridging that gap. This project will distill from this body of work something novel with practical value for California gardeners. The Kemble aloe hybrids considered for this study are: 1. x Gasteraloe ‘luman’: produces rosettes to 1 ‘ in diameter; is a stemless clumper, with spotted leaves that take on a pink, orange and reddish tinge in summer; orange tubular flowers on a branch stock. 3 2018 Saratoga Horticultural Research Endowment Proposal The Ruth Bancroft Garden- Aloe Hybrid Breeding Project 2. Aloe buhrii x reynoldsii, pictured below: produces rosettes to 18 “ in diameter; is a stemless clumper with wide choral edged leaves; much branched flower stalk to 18” high with yellow-orange flowers. 3. Aloe pearsonii x mitriformis pictured below: either upright or horizontal growth clumper with stems of stacked triangular shaped leaves, becoming purple-flushed in sun; red flowers in a round cluster in summer. 4 2018 Saratoga Horticultural Research Endowment Proposal The Ruth Bancroft Garden- Aloe Hybrid Breeding Project 4. Aloe zubb x squarrosa, pictured below: clumper with curled-back, light green heavily spotted leaves; flower stalk is branched with yellow-orange flowers. 5. Aloe ‘Rubin’, picture below: a relatively compact hybrid with four species in its parentage: Aloe humilis and Aloe brevifolia from South Africa, Aloe zubb from Sudan, and Aloe squarrosa from Socatra. It forms mounded clusters