What to Do If Osmanthus Doesn't Bloom? Cause Analysis and Solutions

Osmanthus not only has a pleasant fragrance, but can also be used to make certain foods and is very beneficial to the human body. Osmanthus can now be grown in pots as well, but if not cared for properly, it can easily fail to bloom. So what exactly are the reasons that cause osmanthus not to bloom? And how should it be handled?

Potted osmanthus

1. Improper fertilisation:If nitrogen fertiliser is applied over a long period, it will cause the branches and leaves to grow excessively and affect flowering. Osmanthus prefers fertilisers rich in phosphorus and potassium. Besides using fully fermented organic fertiliser as a base fertiliser when repotting, it should also be given several applications of liquid fertiliser containing phosphorus and potassium before flowering.

2. Insufficient light:The osmanthus tree is a long-day flowering plant. Although it is relatively shade-tolerant, when it is too shaded and receives less than 10 hours of light per day, it cannot bloom normally.

3. Overwatering:This easily causes root rot and leaf drop, affecting flowering. Even if the roots do not rot, it will cause the branches and leaves to grow excessively and fail to bloom. When watering osmanthus, pay attention: water less before new shoots appear, water less on cloudy days, and water more during the hot, dry days of summer and autumn.

4. Failure to repot in time:For potted osmanthus, if it is not repotted for a long time, the root system in the pot cannot spread out, the transport capacity weakens, and it cannot obtain sufficient nutrients, affecting normal growth and development. Therefore, it should be repotted in time.

5. Insufficient low-temperature conditioning:If potted osmanthus is moved indoors too early in winter, and the room temperature is above 10 degrees, it cannot meet the physiological requirement for low-temperature dormancy, which will affect flowering the following year. In the Jiangnan region, potted osmanthus can overwinter on a balcony; not only will it not suffer cold damage, it is actually beneficial for flowering.

6. Effects of smoke and dust:Osmanthus is not tolerant of smoke and dust. If the surrounding air is heavily polluted, it will grow noticeably poorly, the leaves will become smaller and easily fall off, and it will be very difficult for it to bloom. You can take the approach of rinsing it to wash the dust off the leaves, and strengthen management.

Causes and Solutions for Potted Osmanthus Not Blooming

Potted osmanthus is mostly grown from cuttings or grafted seedlings, and the time to flowering is short. Osmanthus grown from cuttings blooms in the fourth year; grafted Golden Osmanthus, Silver Osmanthus and Dan Osmanthus may have 1/5 blooming the following year, while Four-Season Osmanthus blooms that same year. However, in cultivation, quite a few potted osmanthus still fail to bloom when the flowering time arrives. The main reasons osmanthus does not bloom are the following 9 aspects, along with solutions.

Being moved indoors too early, with the temperature above 10°C, means the osmanthus cannot get sufficient dormancy. This causes the osmanthus to sprout and unfold leaves too early, consuming a large amount of nutrients. Combined with insufficient light and a weakened plant, this affects flowering.

After being moved outside in spring, exposure to wind and sun causes the leaf tips to dry up. Even if new shoots appear again, it is not easy for it to bloom.

Insufficient nutrients. Osmanthus is a heavy feeder. Some potted osmanthus are not repotted or given fresh soil for several years, resulting in insufficient nutrition; the root system becomes pot-bound and cannot spread, affecting flowering.

Insufficient light. Osmanthus needs more than 10 hours of light; otherwise the leaves are not lush, which affects flower bud development and prevents flowering. Flower buds are difficult to form. The osmanthus tree by nature likes strong light; only when planted in a spot with ample sunlight and good ventilation, allowing it to fully receive light, can it produce abundant flowers and fragrance. If it is shaded for a long time, it easily causes excessive growth of branches and leaves and affects flower bud formation. In cities with many high-rise buildings, if it only gets a few hours of sun a day, it is difficult for it to bloom. In parks and gardens, which are relatively open, there should be no light problem, but current designs all use high-density planting. Osmanthus trees are arranged in a three-dimensional layout of tall, medium and low trees, with osmanthus in the middle, shading each other, causing insufficient light and making it difficult to bloom.

Overwatering. This causes root rot and leaf drop, affecting flowering.

Too much nitrogen fertiliser. This causes excessive growth of branches and leaves, affecting flowering.

Pollution from smoke, dust and oily grime. Osmanthus is not tolerant of smoke, dust and oily grime. If the leaves are polluted by smoke, dust and oily grime for a long time, growth is poor, and the leaves may even fall off, affecting flowering. Air pollution. The leaves grow smaller and smaller, easily fall off, and there are few flowers, or even no flowers at all.

Lack of pruning. Osmanthus has a well-developed root system and strong sprouting ability. If it is not pruned appropriately, the branches and leaves become too dense, affecting flowering.

Damage from pests and diseases. When it is shaded, humid and poorly ventilated, the disease incidence is severe. After the disease occurs, the leaves turn yellow and fall off, the flowers decrease, and the flowers become smaller.

To make potted osmanthus bloom, corresponding measures should be taken according to the reasons for not blooming.
Ensure low-temperature winter dormancy. The overwintering temperature for potted osmanthus is 3-5°C. Above 3°C, there is no need to move it indoors; keep it at natural temperature. Below 3°C, move it indoors. After being moved indoors, let it go dormant at low temperature, and only then can it grow robustly the next year with abundant flowers and lush leaves.

When moving it outside in spring, it should be moved outdoors on a cloudy day or a rainy day. Never move it outside suddenly on a blazing hot day and expose it to a sudden sun scorching; it should be made to gradually adapt to the outdoor environment.

Ensure long-day light; there should be more than 10 hours of sunlight per day to meet its sunlight requirement.

Water reasonably. It should maintain a water content of 30%; in hot summer, a water content of 60% is appropriate. Do not let it become too dry or too wet.

Nitrogen fertiliser should not be excessive; it should be applied together with phosphorus and potassium fertiliser. Osmanthus needs a lot of phosphorus and potassium fertiliser, and it can be given as a foliar feed by spraying 0.1%-0.2% monopotassium phosphate on the leaves.

Prevent pollution. You can gently wipe the leaves with fine gauze to keep the leaf surface clean, wiping once every 15 days, to facilitate photosynthesis and make the plant grow robustly.

If the potting soil has been in place too long, it should be replaced. Replace the potting soil once every 1-2 years. When repotting, a small amount of hoof pieces can be applied at the bottom of the pot as a base fertiliser.

Prune appropriately. Before moving it outside, cut off diseased and weak branches and overly dense branches, and shorten them appropriately according to the plant shape, so as to improve ventilation and light penetration and promote flowering.

For pest and disease control, scale insects and aphids should be killed, and 70% thiophanate-methyl 1000x solution should be sprayed to treat the disease.

Why Doesn't My Osmanthus Tree Bloom? Causes and Solutions for Osmanthus Trees Not Blooming

Why Doesn't My Osmanthus Tree Bloom

September is exactly the time when osmanthus fragrance fills the air, but there are always some flower lovers who, facing their own osmanthus tree that will not bloom, want to cry but have no tears. Next, Huahua will introduce how to make your osmanthus tree bloom!

1Did You Choose the Right Osmanthus Variety?

First, you need to make sure you have chosen the right osmanthus. There is a type of osmanthus tree called Purple Osmanthus, which only blooms after it has grown into a large tree. So when choosing an osmanthus variety, be careful, and only buy it after confirming with the seller that this potted osmanthus can bloom~

When choosing osmanthus seedlings, it is best to choose grafted seedlings made with mature branches of a good variety as the scion, or seedlings obtained by the air-layering method from flowering branches or even the base, as they are not only of good quality but also easy to bloom after surviving.

2Has Your Osmanthus Tree Reached Flowering Age?

After confirming that you did not choose the wrong osmanthus for your home, next you need to see whether your osmanthus tree has already reached flowering age. The osmanthus tree has a very long lifespan and can basically live for several decades to several hundred years, and some even over a thousand years. If an osmanthus tree has not reached the age, it will not bloom~

Seed-grown seedlings take about ten years to bloom; cuttings take four years to bloom; grafted Golden Osmanthus and Silver Osmanthus have one fifth blooming by the following year; grafted Four-Season Osmanthus blooms that same year, but only very few do.

Some large transplanted osmanthus trees can bloom the same year, while others need one or two years to adapt before blooming.

Of course, as for that last kind of large osmanthus tree, unless you have a big courtyard at home, you had better give up...

3Have You Done the Daily Care of Your Osmanthus Tree Properly?

1. Being moved indoors too early in winter will cause the osmanthus tree not to bloom.

The overwintering temperature for potted osmanthus is 3-5°C. Above 3°C, there is no need to move it indoors; keep it at natural temperature. Below 3°C, move it indoors. After being moved indoors, let it go dormant at low temperature, and only then can it grow robustly the next year with abundant flowers and lush leaves.

2. After being moved outside in spring, exposure to wind and sun causes the leaf tips to dry up. Even if new shoots appear again, it is not easy for it to bloom.

It should be moved outdoors on a cloudy day or a rainy day. Never move it outside suddenly on a blazing hot day and expose it to a sudden sun scorching; it should be made to gradually adapt to the outdoor environment.

3. Failure to repot in time

Some potted osmanthus are not repotted or given fresh soil for several years, resulting in insufficient nutrition; the root system becomes pot-bound and cannot spread, affecting flowering. Therefore, osmanthus needs to be repotted once every two to three years, and repotting should preferably be completed before March, because this is the dormant period of osmanthus, and repotting has less effect on it.

4. Insufficient light

Osmanthus likes light and needs more than 10 hours of light; otherwise the leaves are not lush, which affects flower bud development and prevents flowering.

5. Overwatering

Overwatering can cause root rot and leaf drop, affecting flowering. Watering should follow the principle of "do not water until dry, and when you water, water thoroughly". After heavy rain and torrential rain, promptly pour out any accumulated water in the pot.

6. Too much nitrogen fertiliser and insufficient phosphorus and potassium fertiliser cause excessive growth of branches and leaves, affecting flowering.

Applying phosphorus and potassium fertiliser can promote its transition from the vegetative growth stage to the reproductive stage.

During the spring period of budding and branch growth, apply fully rotted cake fertiliser water and other organic fertiliser liquids. After July, apply fertiliser mainly containing phosphorus, or add 0.5% superphosphate to the fertiliser, to promote flower bud growth.

Osmanthus needs a lot of phosphorus and potassium fertiliser, and it can be given as a foliar feed by spraying 0.1%-0.2% monopotassium phosphate on the leaves.

7. Pollution from smoke, dust and oily grime.

Osmanthus is not tolerant of smoke, dust and oily grime. If the leaves are polluted by smoke, dust and oily grime for a long time, growth is poor, and the leaves may even fall off, affecting flowering. You can gently wipe the leaves with fine gauze to keep the leaf surface clean, wiping once every 15 days, to facilitate photosynthesis and make the plant grow robustly.

8. Lack of pruning.

Osmanthus has a well-developed root system and strong sprouting ability. If it is not pruned appropriately, the branches and leaves become too dense, affecting flowering. Therefore, before moving it outside, cut off diseased and weak branches and overly dense branches, and shorten them appropriately according to the plant shape, so as to improve ventilation and light penetration and promote flowering.

But note that mistakenly cutting off spring shoots will affect flowering that year. Too many blooming osmanthus branches will weaken its growth vigour and affect flowering in the future.

9. Osmanthus likes slightly acidic soil, with a pH of 5.5-6.5 being suitable. Osmanthus grown in alkaline soil often grows poorly and has affected flowering.

There are four commonly used formulas for osmanthus tree nutrient soil:

1. Peat soil 78%-88%, rotted compost 10%-20%, superphosphate 2%.

2. Peat soil and loess, 1/2 each.

3. Peat soil: garden soil or loess, at a ratio of 1:1 or 1:2.

4. Soil or manure soil 98%, superphosphate or calcium, magnesium, phosphorus and potassium fertiliser about 1%, then add an appropriate amount of sterilising and insecticidal pesticides.

10. Osmanthus trees are susceptible to anthracnose.

You can spray 80% mancozeb wettable powder (Daconil) 700 to 800x solution, or 1% half-strength Bordeaux mixture, or 75% chlorothalonil 500x solution for control.

If the disease has already occurred, promptly cut off diseased leaves and fallen dead branches and leaves, and burn them in time, and strengthen ventilation.

11. Osmanthus trees are easily harmed by pests such as scale insects. If not treated in time, this likewise affects flowering.

If scale insects are found, you can repeatedly wipe the affected plant with alcohol, and it will be cleaned very thoroughly.

Okay, that's most of the reasons why osmanthus trees do not bloom~

Hurry and check whether your potted plant has any of the problems above!