Why Don't Dahlias Bloom
This article explains why dahlias fail to bloom and offers some tips on dahlia care based on green plant maintenance experience. Let's delve into the details.
Dahlias are among the world's famous flowers, with numerous varieties. Their advantages include strong adaptability, large blooms, vibrant colors, and a long blooming period. Their blooming period can last from May to mid-November, and under suitable temperature conditions, they can bloom continuously throughout the year, with the most flowers after autumn, making them beloved by many.
Although dahlias are highly adaptable to the environment, many flower enthusiasts have reported that their dahlias bloom very few flowers each year, and some may grow vigorously without flowering. In fact, the situation where dahlias only grow leaves and not flowers is a common occurrence during cultivation. In previous years, I have also grown many dahlias in my garden, and a few of them, due to neglect in care, had fewer blooms or didn't bloom at all. Later, with careful maintenance and management, they produced a abundance of flower buds and bloomed. Therefore, to make dahlias bloom better, it is necessary to care for them according to their growth habits. Next, let's analyze several reasons for the reduced or lack of blooming in dahlias and their respective solutions.
One, unbalanced application of nutrients
Most home dahlias are grown in pots, and due to the limitations of specific environmental conditions, when the nutrients in the potting soil cannot meet the growth needs of the plant, it often leads to yellowing leaves, weak branches, and a failure to bloom. At this point, it is necessary to supplement nutrients through the application of fertilizer, and when fertilizing flowers, it is important to fertilize according to the different characteristics of the flowers. During the growing season, plants require more nitrogen-based fertilizers, as sufficient nitrogen can promote robust and lush growth of branches and leaves; before forming flower buds, it is necessary to reduce the amount of nitrogen fertilizer and switch to phosphorus and potassium fertilizers, which can promote the formation of flower buds. If nitrogen fertilizer is still applied in large quantities before flower bud formation, it will lead to an excess of nitrogen, causing the branches and leaves to grow excessively without flowering.
Solutions
1. Supplement nitrogen fertilizer during the growing season
Fertilizing flowers is like farming; what type of fertilizer to use and when to apply it are based on reasonable requirements, and not just any fertilizer can be used. This also applies to growing dahlias. During the period of leafy growth, it is essential to provide adequate nutrition to make the branches and leaves grow robust, laying a good foundation for later flowering. Nitrogen fertilizer mainly promotes the growth of branches and leaves, so this stage primarily focuses on applying nitrogen fertilizer.
2. Supplement phosphorus and potassium fertilizers before flowering
Dahlias are ornamental flowers primarily grown for their blooms. After the plant has grown to a certain extent, it starts to differentiate flower buds. Flower bud formation and blooming require a large amount of phosphorus and potassium, so it is necessary to supplement phosphorus and potassium fertilizers to promote the formation of flower buds and blooming. If the plant lacks phosphorus and potassium fertilizers, the formation of flower buds will be affected, and the flowering during the bloom season will be scarce, making sufficient nutrients the guarantee for the plant to bloom.
Two, the impact of light on dahlia flowering
Dahlias are mainly grown for their flowers, and light is a key condition for promoting the formation of flower buds. For example, on the same flowering plant, branches that receive sufficient light will produce more and brighter flowers, while those with insufficient light will bloom less. Therefore, adjusting light appropriately can promote flowering in the plant. Dahlias require plenty of light, and without adequate light, they cannot perform photosynthesis, leaving the plant without a source of nutrients and affecting normal growth, thus preventing flowering.
Solutions
1. Light requirements during the growing period
When growing dahlias, special attention should be paid to the impact of light on the plant, as the light requirements of the same flower vary at different stages of growth. From seedlings to mature flowering plants, light exposure should be gradually increased. After flowering, light should be adjusted to extend the bloom period. During the growing period, the plant should receive at least 4-5 hours of sunlight per day. If kept in a shaded environment for extended periods, the plant will develop poorly with thin leaves, slender stems, and pale flowers, or may not bloom at all. Sufficient light results in healthier plant development and more flower buds.
2. Light requirements during the flowering period
Before the plant forms flower buds, ensure adequate light, and after the flowers open, adjust the light accordingly. Since the light requirements during the flowering stage are different, maintaining high light exposure can accelerate the maturation of the flowers, causing them to wilt prematurely. Appropriate shading and reducing light exposure can keep the flowers fresh and extend the blooming period.
Three, the impact of temperature on dahlia flowering
In addition to the direct impact of nutrients and light on dahlia flowering, temperature is also an important condition for flowering. Due to the varying climates in different regions, the temperatures that flowers can adapt to differ, and even the same flower species have different temperature requirements at different growth stages, so maintaining a suitable temperature is an essential guarantee for plant flowering.
High temperatures can cause physiological abnormalities in plants, such as accelerated transpiration that disrupts the plant's water balance, slowing growth, reducing flowering, and shortening the blooming period. Low temperatures can also have a significant impact, often causing frost damage, wilted and soft leaves, yellowing and falling off, and even the entire plant withering, making flowering impossible.
Solutions
When growing dahlias, it is necessary to provide a suitable growth temperature. Generally, the plant can grow normally at temperatures between 10°C and 30°C, with 15°C to 25°C being the most suitable. When the temperature reaches above 32°C, plant growth will be affected and may stop, at which point it is necessary to take measures to cool the plant by moving it to a shaded and well-ventilated area to gradually resume normal growth. Before the plant forms flower buds, the temperature can be controlled between 20°C and 22°C, and the nighttime temperature should not be below 15°C. This temperature range can promote early flowering.
Four, the impact of excessive watering on dahlia flowering
Water is essential for the growth of flowers, but too much or too little water can affect the normal growth and development of the plant. If watering is not done properly, resulting in excessive water in the soil, the oxygen in the soil will decrease, directly affecting the root system's respiration, causing the roots to lose their ability to absorb water and nutrients, leading to root rot, yellowing leaves, and in severe cases, the entire plant withering.
If water supply is insufficient, the roots cannot absorb enough water to meet the growth needs of the branches and leaves, causing them to wilt and possibly dehydrate and wither. Therefore, paying attention to watering and maintaining balanced moisture levels is key to successfully growing dahlias.