When you stroll through gardens and public places, you might notice some Camellia japonicas displaying earlier, larger, and more vibrant blooms than others. This striking phenomenon is often the result of a horticultural technique known as gibbing, in which gibberellic acid is employed to enhance the growth and beauty of these beloved flowering shrubs. In this blog, we’ll delve into the world of gibberellic acid and its application to camellias, shedding light on the fascinating art of cultivating these exquisite blossoms.
Gibberellic Acid: From Classroom Theory to Practical Magic
Gibberellic acid (GA) is a plant hormone or growth regulator that plays a significant role in regulating various aspects of plant growth and development. It is one of the many phytohormones responsible for controlling processes such as germination, stem elongation, flowering, and fruit development in plants.
Gibberellic acid is produced naturally by plants, fungi, and bacteria. It was first discovered in the 1930s when researchers were investigating a rice disease called “foolish seedling,” which caused rice plants to grow abnormally tall and spindly. This disease was later found to be caused by an overproduction of gibberellic acid.
In agriculture and horticulture, synthetic gibberellic acid is often used to manipulate plant growth and development. Some common applications of gibberellic acid in gardening and agriculture include:
- Promoting Germination: Gibberellic acid is used to break seed dormancy and promote germination in seeds that might otherwise be slow to sprout.
- Stem Elongation: It encourages stem and internodal elongation in plants, making them grow taller. This can be useful in certain crops to reduce lodging (falling over) and facilitate mechanical harvesting.
- Flowering Induction: Gibberellic acid can stimulate flowering in some plants, particularly those that require specific environmental cues or conditions to flower. It may be used to promote flowering out of season or in controlled environments.
- Fruit Development: In some fruit trees, gibberellic acid is employed to increase fruit size and promote consistent fruiting.
- Seedless Fruit Production: It can be used to produce seedless fruit in certain varieties.
- Dwarfing Rootstocks: Gibberellic acid can be used to dwarf rootstocks for fruit trees, allowing for easier harvesting and maintenance.
It’s important to note that the use of gibberellic acid in plant growth regulation should be done with care, following specific guidelines and concentrations, as excessive use can lead to unintended effects and potentially harm the plants. Gibberellic acid is just one of several plant hormones, each with its unique role in plant growth and development.
The Gibbing Technique: Enhancing Blooms with Gibberellic Acid
A closer look at your camellia will reveal that most terminal round flower buds have a neighboring, smaller, pointed bud that is vegetative in nature. In simpler terms, this bud will produce a new set of leaves in the spring.
To employ the gibberellic acid technique, a camellia grower pinches off the vegetative bud, leaving a small cup of basal bud scales behind. This cup becomes the site for the application of one drop of gibberellic acid, or it can be placed directly in the wound if a cup isn’t present. Growth activity within the flower bud will become noticeable in about two weeks, and within just five to six weeks, a larger, more vibrant bloom will emerge.
This process entails sacrificing valuable leaves that would have otherwise provided nourishment for the camellia, which is why camellia enthusiasts typically gibb only about 20 percent of a given bush.
Varieties and Variables
While not all camellia varieties respond to gibbing, most common Camellia japonica varieties do. However, predicting precisely when they will bloom can be challenging, as factors such as temperature and humidity also play a role.
Forced Blooming with Gibberellic Acid
Although it is not necessary to apply gibberellic acid for camellias to bloom, it can be a fun and rewarding experiment to encourage early blooming and show family and friends the first flower of the season. Keep in mind that this technique is most effective with winter and spring-blooming varieties, as sasanquas bloom in the fall and do not require gibbing.
Camellia flower buds can be forced into blooming early following treatment with gibberellic acid in late summer or early fall. In many instances, the treated flowers are larger than normal. The process involves applying a solution of gibberellic acid at a concentration of 20,000 ppm (2%) to individual flowers to stimulate them into action.
To apply, select a well-developed flower bud with an upward-facing leaf bud, and remove the leaf bud with a twisting action. Place one drop of acid in the cup left where the leaf bud was removed.
The time required for a treated bud to flower cannot be accurately predicted. Early flowering varieties may bloom within 30 days of treatment, while varieties that normally bloom late often require 60 to 90 days to open.
The timing of gibbing varies, but it usually begins at the end of August or the beginning of September. It’s advisable to gibb at weekly or other intervals rather than in one session. This approach will ensure that you have flowers over a longer period of time. Keep in mind that camellias set flower buds only once a year, so an autumn gibbed bud will not be replaced for spring. Most people like to leave about 80% of buds on a camellia bush untreated. Apply gibberelic acid very sparingly to a young plant.
Camellias, with their glossy green leaves and exotic, breathtaking blooms, are an asset to any landscape. By exploring the world of camellias and embracing the gibberellic acid technique, you can not only enhance the beauty of your garden but also join a community of passionate gardeners who are eager to share their knowledge and expertise. Whether you’re an aspiring camellia grower or an experienced enthusiast, the world of camellias offers a delightful journey of horticultural discovery. And for those looking to experiment, gibbing offers an exciting way to force early blooms and share the joy of the first flowers of the season with your loved ones.
If you would like to learn more about camellias, or purchase some of your own, the Coastal Georgia Camellia Society is hosting their Fall Camellia Festival at the Coastal Georgia Botanical Garden on Saturday, November 11th, 2023 from 10:00 a.m. – 4:00 p.m. Admission to the Gardens is $5 for adults (ages 17+), $3 for children ages 6-16, and free for children 5 & younger. The event will feature tours of the Judge Arthur Solomon Camellia Trail, plant sales, and a camellia exhibition. Learn more at https://coastalgacs.wildapricot.org/page-18123.