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Propagation Treasures from the IPPS "Black Books"
Editor’s note:
Greetings! Each month in the newsletter, I plan to share a summary of interesting and relevant papers on propagation and production from the IPPS Black Books – known today as the “IPPS Proceedings” on the IPPS website. These articles, focusing on propagation and production, are an incredible resource that deserve more attention and use.
This month’s featured article highlights that many of the techniques employed over 70 years ago continue to have practical applications in today’s industry – a testament to the enduring value of “seeking and sharing”.
Ryan Stewart
Editor of the Western Region of the International Plant Production Society
The grafting of some maples
By J. Howard Burton, Hill Top Nurseries, Casstown, Ohio (Volume 2, p. 71-80, 1952)
This month, we revisit J. Howard Burton’s information-packed presentation at the annual meeting of the International Plant Propagator’s Society in 1952, offering insights into maple grafting. Drawing on over three decades of experience, Burton shared his techniques and observations on propagating Japanese maples, red maples, sugar maples, and other maple species. His advice still has application to plant propagators today with his emphasis on practical problem-solving and attention to detail.
Key lessons from Burton’s experience
Burton highlighted the importance of selecting high-quality, uninjured scion wood to ensure grafting success. He also stressed the need to carefully match scions with appropriate rootstock, noting that some combinations, such as black maple on sugar maple rootstock, proved to be particularly challenging. In his words, “The less said…the better.” 😊 Despite these difficulties, Burton’s experiments reflected the trial-and-error nature of propagation and the persistence required to refine techniques – both of which are still, for better or worse, some of the hallmark aspects of propagation.
Two seasons, two approaches
Burton compared summer and winter grafting, detailing the unique advantages and challenges of each method:
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Summer grafting: Conducted in July or early August, this method allowed propagators to verify scion viability immediately. Burton recommended shading grafts with canvas, using sand or peat media, and syringing [which I believe means to lightly apply water to plants with a syringe] the grafts during the critical early days to prevent wilting. While summer grafting yielded dormant plants ready to handle by spring, it required meticulous control of temperature and humidity to avoid damage to tender scions.
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Winter grafting: Performed before rootstocks broke dormancy, winter grafting minimized initial environmental challenges, but posed a risk of scions leafing out and wilting before establishing a connection with the rootstock. Burton found that slight root activity in the rootstock improved scion success, emphasizing the importance of timing and preparation.
Practical techniques for success
Burton shared several tips that remain relevant for propagators today:
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Wax for scion protection: He dipped scions in wax to preserve moisture, finding this technique reduced scion loss in both summer and winter grafting.
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Ventilation to prevent mold: Proper ventilation of grafting cases was crucial, particularly as buds began to break. This helped minimize the risk of fungal issues.
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Plunge grafting media: Burton preferred plunging [the practice of partially burying containers, pots, or plant material into loose, well-draining media, such as peat mix or sand] grafts in a damp but not overly wet media, ensuring the graft union was covered but not tightly packed.
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Rootstock maintenance: Cutting back the rootstock helped reduce crowding and supported scion health during early growth stages.
Lessons learned
Burton shared candid accounts of setbacks, such as mold on Japanese maple leaves during case [cold frame?] grafting and the challenges of grafting black maple on sugar maple. His openness about failures underscored the importance of experimentation and adaptability in propagation.
Summary of the discussion following Burton's presentation
After Burton’s presentation on grafting maples, attendees engaged in a discussion that expanded on his techniques and experiences. The conversation covered practical details, challenges, and alternative methods for grafting and propagating maples. Here are the key points from the discussion:
1. Waxing scions and union care
Burton was asked about his use of wax for scions. He clarified that scions were dipped in wax before grafting but not painted at the union afterward. Other participants discussed their own innovations, including a tool for efficiently dipping scions into wax and the benefits of using cotton twine coated with paraffin to avoid girdling during the healing process.
2. Temperature control
Temperature management was a significant topic. Burton emphasized the importance of maintaining stable conditions in both summer and winter grafting. He noted the challenge of overheating in summer frames or greenhouses and highlighted the use of shading and careful ventilation to reduce stress on tender scions. One participant suggested briefly subjecting grafts to cooler temperatures to break dormancy, but Burton and others warned that this could be fatal for tender scions.
3. Grafting media and plunging
Attendees discussed the use of different media for plunging grafts. Burton preferred sand or peat mixtures, emphasizing the need to avoid overly wet conditions that could lead to rot. Others noted the importance of aeration and suggested adjusting media pH for better outcomes with certain maple varieties.
4. Challenges with Japanese maples
Several participants shared their struggles with propagating Japanese maples, particularly from cuttings. While some reported success in rooting, many highlighted difficulties in overwintering rooted cuttings due to rotting at the callus or root tip. One participant attributed these failures to pH imbalances in the growing medium.
5. Rootstock-scion compatibility
The issue of rootstock-scion compatibility was raised, particularly in relation to red maple grafted onto silver maple and black maple grafted onto sugar maple. While red maple grafts on silver maple rootstock performed well, others shared concerns about graft unions weakening over time, leading to tree failure.
6. Alternative propagation techniques
Participants discussed the potential for propagating maples through cuttings, referencing experimental work on rooting various species under mist and in closed cases. Some attendees shared successful techniques for rooting Japanese maples but noted the challenges of maintaining plant health through winter.
7. Practical tips for grafting success
Burton and others reiterated several practical tips for improving grafting outcomes:
- Use side branches as scions for better hardiness.
- Ensure proper shading for grafts during early establishment.
- Ventilate frames frequently to prevent mold.
- Avoid rubber bands for securing grafts, as they can cause girdling.
The discussion reflected the collaborative spirit of the IPPS community, with participants sharing their successes, failures, and experimental methods. While challenges in grafting and propagating maples were acknowledged, the exchange of ideas underscored the value of continuous learning and innovation in the field of plant propagation.
This dialogue, filled with practical insights and creative solutions, exemplifies the IPPS motto: “To seek and to share.”
Why it still matters
Though technology has advanced since 1952, Burton’s insights into maple grafting remain highly applicable. His dedication to mastering the fundamentals of propagation, such as maintaining optimal environmental conditions and selecting suitable materials, reflects the enduring principles that guide our industry today.
Burton’s wisdom serves as a powerful reminder that success in propagation lies in a balance of science, craftsmanship, and a willingness to learn from experience. As propagators, we continue to “seek and share” knowledge, building on the foundation laid by early production professionals like Burton.
Stay tuned for more inspiring summaries of informative papers from the IPPS Proceedings (the revered Black Books)!
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