Reasons for Yellowing and Falling Leaves on Four-Season Osmanthus and How to Fix Them

Although the four-season osmanthus (Osmanthus fragrans) is grown for its flowers, its leaves are also quite attractive and have their own distinctive character. Moreover, for any plant, yellowing or falling leaves will affect its appearance. When this problem arises during cultivation, how exactly should we solve it? Let's take a look together below.

What to Do When Four-Season Osmanthus Leaves Turn Yellow

1. If it is confirmed that the soil properties are unsuitable, you can consider using acid to adjust it. Generally we use ferrous sulfate; just soak it in water and pour it onto the soil, or we can repot the plant to change the soil it grows in, which is also a fairly direct method.

2. If overwatering is the cause, placing it in a relatively dry spot is one way to let the water drain away, and putting it in a ventilated place is another; of course, doing both together is even better.

3. If we apply too much fertilizer, it can also cause its leaves to turn yellow. Of course, this is still affected through the roots, because they may be burned and indirectly affect the leaves. At this point, choosing to flush the fertilizer away with water is a fairly wise method.

4. If the temperature is relatively low, that is also a cause of yellow leaves; below 10 degrees it will grow yellow leaves. At this time we should appropriately raise the temperature.

Solutions for Four-Season Osmanthus Dropping Leaves

1. Young trees need some shade; once mature, they require relatively sufficient light to ensure the normal growth of osmanthus.

2. Four-season osmanthus is suitable for planting in ventilated and well-lit places; it likes a clean, airy environment and is not tolerant of smoke and dust damage.

3. In routine care and management of four-season osmanthus, if leaf blight occurs, it can also lead to leaf drop. Four-season osmanthus leaf blight mostly invades from the leaf margins and leaf tips, occurring at the leaf margins and tips, so it should be prevented in advance.

Propagation Methods for Four-Season Osmanthus

1. Softwood cuttings: Select excellent mother plants with superior varieties, vigorous growth and no pests or diseases for collecting cuttings. When preparing the cuttings, cut them into 2-3 cm lengths, keep 1-2 leaves at the top, cut the upper end flat and the base into a slanted surface; the slanted surface should be smooth to facilitate rooting and healing. After disinfecting the cuttings, soak them in rooting powder for 10 minutes before inserting them. After inserting, water promptly and cover with plastic film and a shade net or straw curtain. Spray a 2000-fold carbendazim solution once every 7 days, and spray a 0.2% urea or monopotassium phosphate solution once every 10 days.

2. Air layering: The air layering method is mostly carried out before spring budding, and can also be done during summer growth; doing it during the plum rain season also gives very good results. On one- or two-year-old branches, make a notch or a ring of bark removal, fill with substances such as rice husk ash, moss, potting soil, perlite, etc., then wrap the wound. Keep it moist frequently, but do not use too much water. Once roots have formed, it can be cut away from the mother plant.

3. Rootstock grafting: The rootstocks mainly used for grafting four-season osmanthus include privet, white ash, lilac, fringetree, etc. The disadvantage of privet as a rootstock is that its root system is overly developed, making it unsuitable for pot cultivation, and it also blooms late. The disadvantage of white ash as a rootstock is its short lifespan, and it tends to drop leaves in winter and blooms relatively little. With lilac as a rootstock, the trunk is thick at the top and thin at the bottom, giving the tree a top-heavy shape. Fringetree as a rootstock has good compatibility, drought and cold resistance, strong adaptability and a long lifespan, with trees living more than a hundred years. Therefore, the most suitable rootstock for potted osmanthus grafting propagation is fringetree.

Notes on Growing Four-Season Osmanthus

1. Soil mix: Four-season osmanthus is suitable for growing in loose, fertile, well-drained acidic soil. Generally, use 60% broadleaf humus soil, 25% coniferous humus soil, 10% river sand or fine furnace ash, and mix in 5% well-fermented pig manure or chicken manure.

2. Light: Four-season osmanthus likes light. When grown indoors, it should be placed in a sunny and ventilated spot, keeping light exposure at 8 to 12 hours per day.

3. Temperature: Four-season osmanthus likes warmth, generally growing well at 18°C to 25°C, blooming abundantly and with a fresh fragrance. If below 15°C, it enters a semi-dormant state and blooms less. It can overwinter at 3°C to 5°C, but cannot bloom.

4. Humidity: When cultivating four-season osmanthus, you must keep the potting soil moist, but not waterlogged. When watering, follow the principle of watering when dry and stopping when wet, and never allow standing water, so as to avoid root rot or leaf drop. Especially when flowering, water should not be too much, to avoid bud drop and affecting flowering.

5. Fertilizing: Four-season osmanthus likes fertilizer. During the sprouting and bud-setting periods, apply more diluted fertilizer water containing phosphorus and potassium, so that the branches and flower buds grow strong. Especially a few days before flowering, applying some diluted fertilizer water will make the flowers larger, more colorful and more fragrant.

It seems that growing four-season osmanthus still requires attention to method. If cared for improperly, yellowing leaves and leaf drop are very likely to occur. Above, we have introduced the issues to watch out for during cultivation, which can effectively prevent problems that easily arise during growing. In fact, as long as you care for it attentively, you can still grow four-season osmanthus well.