American Camellia Society Camellia Growing Tips & Culture
American Camellia Society The Garden Report: Questions & Answers
Norfolk Botanical Garden Hofheimer Camellia Garden
The use of gibberellic acid by camellia growers is a popular practice in the United States. Camellia flower buds can be forced into blooming early following treatment with gibberellic acid in late summer or early fall. This has become popular because hard winter freezes frequently injure Camellia japonica flowers when they are in bloom. Also, in many instances, the treated flowers are larger than normal. Those entering blooms in camellia shows frequently gib to produce larger blossoms.
Gibberellins are growth-regulating chemicals produced by most plants in very small quantities. The gibberellin used by camellia enthusiasts is gibberellic acid. The process of applying the chemical to camellias is often called "gibbing".
Investigation of the use of gibberellins in agriculture began in 1950 in the United States, but camellia growers did not become actively involved in testing gib until the 1960's. The exact process by which gibberellins work on camellias is not fully understood. Research by U.S.D.A. scientists indicates that disappointing results will usually be obtained when "gib" is applied to shrubs and flowers other than camellias. The result is usually a stretching of growth or elongation of the stems. In camellias, the application of gibberellic acid will break dormancy of the flower bud and enlarge the bloom size.
A solution of gibberellic acid must be applied to individual flower buds to stimulate them into action. See illustration below. The flower bud is plump and round where the vegetative bud is smaller and pointed. To treat, select a vegetative bud next to a plump, well-developed flower bud. Twist out the vegetative bud leaving a "cup" of bud scales at the base. Place a drop of the solution into this cup. The chemical will be translocated to the flower bud, which should begin noticeable growth activity within two weeks.
Testing over the years has proved the time required for a treated bud to flower cannot be accurately pre-determined. The general condition of the plant, the size of the flower bud, and the weather are a few of the variables which affect the time element. Considerable variation occurs among varieties. Early flowering varieties may bloom within 30 days of treatment; varieties that normally bloom late often require 60 - 90 days to open.
The time when first to apply gib differs geographically. It is usually the end of August or the first of September before the flower buds are well-formed enough. It is best to gib weekly or at other intervals rather than in one session. This will ensure that you have flowers over a longer period of time. Camellias set flower buds only once a year, so an autumn gibbed bud will not be replaced for spring.
The larger the bush, the more buds you can treat. Most people like to leave about 80% untreated. Apply gib very sparingly to a young plant. The terminal vegetative buds on treated stems usually fail to make normal growth in the spring. Therefore, it is usually best to cut treated flowers or to prune the stems back.
Gibberellic acid solution can be bought at our workshops. In addition, we teach gib application and advantages. Come out and join us at the workshops.
Also, gibberellic acid may be purchased from the American Camellia Society in the powdered form. It is easy to mix and comes with instructions. One gram will treat a few hundred flower buds.
Gibbing camellia flowers buds is easy. Select well developed flower bud, remove vegetative bud beside the flower bud and place one drop of acid in the cup left where the vegetative bud was removed.
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