Why won't potted hydrangeas bloom?
Hydrangea, also known as shade hydrangea and zi yang hua, is a semi-evergreen or deciduous shrub with large, opposite, glossy leaves. Its flowers are large and brilliantly colored, and the flower color is variable, changing with the acidity or alkalinity of the soil. When first open they are as white as snow, and later gradually turn light blue or pale red. Each flower cluster can bloom for 1-2 months. It is suitable both for courtyard cultivation and for growing in pots at home. However, when grown in pots at home, if care is improper, it often struggles to bloom. The main reasons are as follows:
(1) Too much nitrogen fertilizer: Hydrangea grows vigorously and has a fairly high fertilizer demand. From after flowering to the flower bud differentiation stage, fertilization should focus on nitrogen, while during the flower bud differentiation stage it should focus on phosphorus and potassium. If, during the short-day flower bud differentiation stage in autumn and winter, nitrogen fertilizer is still applied in excess, it causes excessive vegetative growth and inhibits reproductive growth, so flower buds cannot form, and blooming is difficult in early summer of the following year.
(2) Too little light: When grown at home, limited conditions mean too little light, which easily causes leggy branches and leaves and poor growth. By the time of flower bud differentiation, nutrition is insufficient, so flower buds cannot differentiate normally.
(3) Too long a light period: Hydrangea is a short-day flower, and during its flower bud differentiation the photoperiod must not exceed 10 hours. If grown at home indoors, long hours of indoor lighting at night will affect flower bud differentiation.
(4) Indoor room temperature too high in winter: Hydrangea needs a period of relatively low temperature during flower bud differentiation, with the temperature controlled at 5-10 degrees C for about one and a half months. If grown at home in a warmer room in winter, the flower buds cannot differentiate normally.
(5) Improper pruning time: The normal flowering period of hydrangea is June to July. Generally, after the flowering period the flowering branches should be cut off, and heavy pruning can also be done. If the branches are heavily pruned in early spring, it is very difficult to form effective flowering branches in June to August, resulting in reduced or no flowering.
Why hydrangeas don't bloom and what to do if your hydrangea won't bloom
Hydrangea, also known as eight immortal flower, and also called zi yang hua and shade hydrangea, usually blooms from June to July. Hydrangea has thick, sturdy stems, large leaves and deep green foliage, but many hydrangeas do not bloom. So why don't hydrangeas bloom? What should you do if your hydrangea won't bloom?
Potted hydrangea has not been pruned:
Usually, after the flowers fade, the branch tips should be cut short in time to encourage new branches to grow. When the new branches reach 8-10 cm, they can be cut back again, which encourages the lateral buds on them to develop and fill out early, and only in this way can flowering branches grow the following year. In other words, pinching back suppresses the plant's vegetative growth to encourage more lateral branches and the formation of flower buds.
The fertilizer ratio for hydrangea is unbalanced:
There may be too much nitrogen fertilizer and too little phosphorus and potassium fertilizer, causing excessive vegetative growth, which is unfavorable for flower bud formation and prevents the plant from blooming normally in the second and third years.
It may be because of too much watering:
After the plant's new shoots reach a certain length, water should be withheld appropriately to suppress vegetative growth and encourage flower bud differentiation.
Light duration is not controlled appropriately:
Hydrangea is a short-day plant. Maintaining darkness for more than 10 hours per day for about 6 weeks is needed for flower buds to form. For forced cultivation, after the plant goes through a 6-8 week cool period (5-7 degrees C), place it at 20 degrees C to force flowering. When the flower clusters become visible, lower the temperature to about 16 degrees C, and after maintaining this for about 2 weeks it will bloom.
When do hydrangeas bloom and why don't hydrangeas bloom
Hydrangea is a famous ornamental plant of the Yangtze River basin, also known as eight immortal flower, powder ball flower and grass hydrangea. Its flowers are large and beautiful, with full, big and lovely flower forms, and the color can be red or blue. So when do hydrangeas bloom? Why don't hydrangeas bloom?
When hydrangeas bloom:
Hydrangeas generally bloom from June to August, and the time from opening to fading is about 25 days. The flower color of hydrangea is pink, light blue or white, but the color changes with the acidity or alkalinity of the soil or medium. To deepen the blue, aluminum sulfate can be applied during the bud formation stage; to maintain pink, lime can be applied to the soil.
Why hydrangeas don't bloom:
1. Too much nitrogen fertilizer: In the early stage of hydrangea flower bud differentiation, nitrogen fertilizer is the main focus, and during the differentiation stage phosphorus is the main focus. However, if nitrogen and phosphorus fertilizers are applied in excess in autumn and winter, it causes excessive nutrition in the plant, growth is inhibited, flower buds are difficult to differentiate, and flowering the following year is affected.
2. Too little light: Hydrangea grown at home is limited by conditions and receives less light, which causes leggy leaves and poor growth. The leaves consume too much nutrition, so at the time of flower bud differentiation there is insufficient nutrition, affecting flowering.
3. Too long a light period: Hydrangea is a short-day plant, and during the flower bud differentiation stage the light period must not exceed 10 hours. For eight immortal flower kept in living rooms, long hours of lighting at night increase the light exposure and affect flower bud differentiation.
4. Improper pruning: The flowering period of hydrangea is June to August. After the flowering period, the flowering branches should be pruned to reduce nutrient loss. If the plant grows too vigorously and is heavily pruned again in early spring, it is very difficult to form flowering branches in June to August, resulting in reduced or no flowering.
How to grow hydrangeas well:
1. Soil: Hydrangea prefers loose, fertile, well-drained sandy loam, but changes in soil pH greatly change the flower color of hydrangea. To deepen the blue, aluminum sulfate can be applied during the bud formation stage; to maintain pink, lime can be applied to the soil.
2. Watering: The potting soil of hydrangea should be kept moist, but watering should not be excessive. Especially in the rainy season, pay attention to drainage to prevent waterlogging from causing root rot. In winter, potted plants indoors are better kept slightly dry. If too wet, the leaves are prone to rot.
3. Light: Hydrangea is a short-day plant. In ordinary cultivation, avoid direct scorching sunlight, and 60-70% shade is ideal. When the light is too strong in midsummer, appropriate shading can extend the viewing period of the flowers.
4. Temperature: The suitable growth temperature for hydrangea is 18-28 degrees C, and the winter temperature should not be lower than 5 degrees C. Flower bud differentiation requires 6-8 weeks at 5-7 degrees C. A temperature of 20 degrees C can promote flowering, and after the flowers appear, maintaining 16 degrees C can extend the viewing period. Note that high temperatures make the flowers fade quickly.
5. Fertilizing: Hydrangea should generally be given a dilute cake fertilizer solution once about every 15 days. To keep the potting soil constantly acidic, 0.2% ferrous sulfate can be added when applying liquid fertilizer to turn it into alum fertilizer solution for watering, and during the bud stage, 1-2 applications of 0.5% superphosphate soaking solution should be added.
6. Pruning: After hydrangea blooms, pay attention to removing the flower stems to encourage new branches. Proper pruning can keep the plant shape graceful. In early spring in March, diseased and dead branches and weak, slender branches should be cut off from the base, keeping 3-5 healthy main branches and cutting them back, leaving 2-3 buds on each branch.
7. Pests and diseases: Hydrangea mainly suffers from wilt disease, powdery mildew and leaf spot disease, which can be prevented and controlled by spraying 600 times dilution of 65% zineb wettable powder. Insect pests include aphids and mirid bugs, which can be killed by spraying 1500 times dilution of 40% omethoate emulsifiable concentrate.
8. Repotting: Hydrangea generally needs to be repotted and have its soil changed once a year. When repotting, cut off decayed roots, rotten roots and overly long fibrous roots. After the plant is moved into the new pot, press the soil firm, water thoroughly, place it in a shaded spot for about 10 days, and then move it outdoors for normal care.