Foliar application of plant growth regulators affecting vegetative and flowering traits in mop-head hydrangea (Hydrangea macrophylla)

Hydrangea is one of the world's most charming and wonderful ornamental plants. In recent years
hydrangeas have been used commonly as cut flowers, potted plants, and garden plants with a
gradual increase in popularity and production worldwide. The present study was conducted to
investigate the effect of foliar application of plant growth regulators on Hydrangea macrophylla.
The study provides valuable information for optimizing hydrangea growth and development
through the use of PGRs. It focuses on the factors such as plant height, flower size, and overall
aesthetics. The treatments comprised of different plant growth regulators at different
concentration i.e., gibberellic acid (GA 3 : 25 ppm, 50 ppm, and 100 ppm), benzyladenine (BA: 50
ppm, 100 ppm, and 150 ppm and giberellin in combination with benzyladenine (GA 4+7 @ +BA:
50 ppm, 150 ppm, and 250 ppm). From the data, it was revealed that the use of different PGRs
had a significant effect on all the vegetative and floral parameters of the plants. The plants
treated with GA 3 @ 100 ppm had maximum plant height (39.60 cm), the maximum length of
shoots (27.51 cm), minimum days taken for visible bud formation (151.47 days), and minimum
days for flowering (184.53 days). In addition, maximum pot presentability (88.17) and growth
index (35.81) were recorded in the plants with the application of GA 4+7 @ 50 ppm+BA @ 50
ppm. Thus, the study indicated that hydrangea plants treated with GA 4+7 @ 50 ppm + BA @ 50
ppm resulted in the most desirable and presentable potted plants. By providing insights into the
effective use of PGRs, the study can help growers optimize plant production, improve plant
quality etc.