How much does temperature affect flower growth?
Temperature is an important factor affecting flower growth. Common flowers can generally grow within the range of 4 to 36°C, and within this range, as the temperature rises, the growth rate gradually accelerates. Within the suitable temperature range, the physiological activities of flowering plants are most vigorous and the growth rate is fastest. When the temperature falls below or exceeds the suitable range, and the humidity continues to decrease or rise, growth will slow down, or even stop and enter dormancy. For example, Cyclamen grows slowly below 10°C, 15-25°C is its suitable growth temperature, and high temperatures above 30°C are unfavorable for its growth. Because various flowers originate from different climates, the temperature ranges they can adapt to also vary greatly. Each flower has its own optimum growth temperature, maximum temperature and minimum temperature. According to their adaptability to temperature, flowers can be divided into non-cold-resistant flowers, semi-cold-resistant flowers and cold-resistant flowers.
The effect of temperature on flower dormancy
Flower growth generally undergoes changes of adverse seasonal climates, especially temperature changes, such as dry heat and high temperatures or severe cold. Flowers often adapt to temperature changes through dormancy. During dormancy, the physiological activities of flowering plants are in a stagnant state, so as to survive the adverse climate. For example, flowers such as Cyclamen and Tulip enter dormancy in the hot summer. While flowers such as Peony, Chinese Rose and Pomegranate shed their leaves and enter dormancy when winter comes. During dormancy, fertilization is generally stopped, watering is reduced, and cooling and ventilation are provided, so that they can safely pass through summer or winter. Flowers such as Fuchsia, Calla Lily and Geranium are in a state of slow-growing semi-dormancy during the high-temperature season.
The effect of temperature on flower bud differentiation. The flower bud differentiation of various flowers requires a certain temperature. Spring-sown annual herbaceous flowers must undergo appropriate high temperatures to form flower buds and bloom, while autumn-sown flowers must undergo a period of low temperature before they can form flower buds. We call the process by which low temperature promotes flower bud formation in overwintering flowers the vernalization stage, and the low-temperature treatment process that enables flowers to pass through the vernalization stage is called vernalization. Therefore, the temperature can be artificially lowered to promote flower bud differentiation in flowers, so as to promote plant flowering.
Suitable growth temperatures for various flowers. Various flowers each have their suitable growth temperature, and temperatures that are too high or too low are harmful to flower growth. In the high-temperature season, flowers have a large amount of water transpiration, and if water absorption is insufficient, plants are prone to death. The tolerance of various flowers to high temperatures is different. Aquatic flowers such as Lotus and Water Lily, Cactus and succulent plants, as well as annual herbaceous flowers and summer-blooming flowers such as Milan, Jasmine, Orange Jessamine, Hibiscus and Crape Myrtle have relatively strong high-temperature tolerance. Flowers blooming in spring and autumn, such as Chrysanthemum, Peony and Dahlia, have slightly weaker heat tolerance. Some autumn-planted bulbous flowers such as Calla Lily, Cyclamen, Amaryllis and Fuchsia and Clivia are not tolerant of high temperatures and need good heat protection and cooling measures, otherwise they often suffer yellowing and shedding of leaves, poor growth or even death.
When low temperatures fall below freezing point, most southern flowers and herbaceous flowers cannot grow. However, the low-temperature tolerance of flowers is different. Autumn-sown herbaceous flowers such as Dianthus, Pansy, Daisy and Calendula can overwinter in the open field, while highly cold-resistant plants such as Wintersweet and Plum Blossom can still bloom at low temperatures.