How to grow potted four-season osmanthus? A detailed guide to care methods

Four-season osmanthus is a variety of Osmanthus in the genus Osmanthus, also known as monthly osmanthus, laurel, etc. It is an evergreen small tree or shrub of the Oleaceae family and the Osmanthus genus. Its biggest difference from other osmanthus varieties is that it blooms year-round, that is, it blooms in all four seasons, but its fragrance is also the weakest among the many osmanthus varieties, with almost no detectable floral scent. Now let us take a look at how to grow potted four-season osmanthus!

Growth habits of four-season osmanthus

Four-season osmanthus likes a warm and humid climate. Osmanthus prefers a warm and humid climate and has a certain cold resistance, but it is not tolerant of severe cold. It likes light and also tolerates shade, and seedlings need a certain degree of shading. It does not have high requirements for soil, preferring slightly acidic soil on high, dry terrain rich in humus, with deep, fertile, moist, well-drained sandy soil being most suitable. It is not tolerant of drought and poor soil, and avoids saline-alkaline soil and waterlogged land. Planting it in overly wet land with poor drainage will cause poor growth, root rot, leaf drop, and eventually the death of the whole plant.

Propagation methods of four-season osmanthus

1. Grafting: The rootstock can use privet, small-leaf privet, ash, and fringetree, etc. For mass propagation, small-leaf privet is often used. Before spring sprouting, cut the rootstock 5 cm above the ground, cut 1- to 2-year-old strong osmanthus branches 10 to 12 cm long, and cut both sides of the base into 45-degree slanted surfaces. Make a vertical cut about one-third of the way along one side of the rootstock, 2 to 3 cm deep. Insert the scion into the cut, align the cambium, tie it tightly with a plastic bag, and bury it in soil for cultivation.

2. Cuttage: Before spring sprouting, select fully developed one-year-old branches and cut them into 5 to 10 cm lengths. Remove the lower leaves, keep 2 to 3 leaves at the top, and insert them into a river sand or loess seedbed with a plant and row spacing of 3×20 cm. After insertion, water and shade promptly, maintain a temperature of 20°C to 25°C and a relative humidity of 85% to 90%, and roots can form in 2 months.

3. Layering: There are two types, low layering and air layering. For low layering, choose a low-branching or clumping osmanthus mother plant, and from spring to early summer cut or girdle the lower 1- to 2-year-old easily bendable branches with a sharp knife, reaching the xylem, press them into a 3 to 5 cm deep trench, and fix them with wooden strips. For air layering, in spring select 1- to 2-year-old branches from the mother tree, girdle them, wrap the wound with culture medium, and tie the plastic bag tightly. During cultivation, always keep the medium moist, and after roots form in autumn, cut them away from the mother plant.

How to grow potted four-season osmanthus?

1. Soil: Four-season osmanthus likes to grow in slightly acidic soil. It can be cultivated by mixing peat, garden soil, sandy soil, and river sand, with a pH value of 5.5 to 6.5. Before potting, disinfect the prepared soil with a potassium permanganate solution. It is best to use tiles, as they have very good water permeability and air permeability. The potting soil substrate is effective, and generally the pot should be changed once every 1 to 2 years, in early spring, which is more beneficial to plant growth.

2. Watering: Four-season osmanthus likes a high-temperature, dry environment, so watering must be well controlled. In summer, water more, keeping soil moisture at around 50%, which is most suitable. During rainy weather and sprouting, water less to avoid water accumulation in the pot and prevent root rot. In summer, provide shade, the temperature must not exceed 35°C, and spraying water around the flower pot can achieve a cooling effect.

3. Fertilizing: When growing, four-season osmanthus likes organic fertilizer. When four-season osmanthus sprouts, fertilize carefully once every week, using decomposed diluted liquid fertilizer or pig manure liquid. In July, use organic compound fertilizer, and in September, apply phosphate fertilizer, so that four-season osmanthus grows more luxuriantly, thereby improving its ornamental value.

4. Temperature: Four-season osmanthus can be cultivated outdoors for overwintering in areas south of the Yellow River basin. Potted plants should be moved indoors in winter and placed in a sunny place so they can fully receive direct sunlight, with room temperature kept above 5°C but not exceeding 10°C. After sprouting in April of the following year, move them outdoors, first placing them in a sheltered, sunny spot for care, and after stable growth gradually move them to a ventilated, sunny or semi-shaded environment, then carry out normal management.

5. Pruning: Four-season osmanthus can be pruned in spring and autumn. The first time is after flowering in autumn, then trim off the relatively long and overly dense branch tips, leaving stout short branches. The second pruning is in early spring before sprouting, removing dead branches, weak branches, and diseased branches so it can sprout better. Generally, it is enough to meet the requirements of being short and sturdy, with a thick trunk and evenly arranged branches and leaves.

Precautions for four-season osmanthus

1. Four-season osmanthus must be given sufficient fertilizer. In particular, insufficient phosphorus will affect the branching of the osmanthus tree, and the flowers will be few and not fragrant. Four-season osmanthus has a well-developed root system, and mature four-season osmanthus sends out new shoots every spring and autumn, so attention should be paid to pruning to maintain a beautiful plant shape, balance the physiological nutrition of four-season osmanthus, and promote flower bud growth.

2. When watering four-season osmanthus, note that before new shoots grow, water less; on rainy days, water less; in dry weather in summer and autumn, water more; and when flowering in autumn, control the amount of water to keep the pot soil moist, as excessive moisture will cause flowers to drop.

3. Four-season osmanthus suffers from relatively many diseases and pests. Diseases include brown spot disease, blight spot disease, anthracnose, etc., and pests include red spiders and white peach scale, etc. Corresponding medicines can be used to eliminate them or they can be removed by hand.