A Detailed Guide to Making and Caring for Wintersweet Bonsai

Wintersweet, also known as yellow-flowered plum, thousand-branch plum, fragrant plum, etc., is a plant of the genus Chimonanthus in the family Calycanthaceae. It is native to central China and is most famous in Yanling, Henan. It can be grown in the ground, in pots, and is especially an excellent material for making bonsai. Below, let us take a look together at the making and care of wintersweet bonsai!

Sources of Tree Stumps for Wintersweet Bonsai

1. Sowing: The sowing time for wintersweet is to collect seeds in June, and sowing right after collection is best. Before sowing, soak the seeds to hasten germination for 24 hours to ensure uniform seedlings and early germination. They germinate in 10 days, and the seedlings grow 10-20 cm tall in the current year. Generally, seedling-grown plants begin to bloom in 3-4 years.

2. Layering: After girdling the root in spring, mound soil for layering, or air layering can also be done during the plum rain season (late June to mid-July).

3. Division: Division propagation of wintersweet is generally carried out in spring between February and March, when the leaf buds have not yet sprouted. When dividing, first dig away the soil on the side of the mother plant's root near the offset, use a sterilized sharp knife to cut the offset and its root fibers away from the mother plant's roots, forming a new plant. Then plant it, taking care to shade it after planting and keep the soil moist. After the dog days pass, apply liquid fertilizer once every half month, and it can grow vigorous branches and leaves in the same year, blooming after 2-3 years. This propagation method is simple and easy, has a high survival rate, short seedling-raising time, and quick flowering.

4. Grafting: Use red-hearted wintersweet seedlings or divided plants as rootstock. Yangguang Nursery Stock Network suggests using cut grafting, approach grafting, or bud grafting, with cut grafting being the most commonly used. Cut grafting is carried out from March when the leaf buds sprout until the leaves are the size of wheat grains; approach grafting is best in the transition between spring and summer, in May-June; bud grafting is carried out in July-August. The time for cut grafting is around mid-March, best done when the wintersweet leaf buds have just sprouted to the size of a grain of rice. If the timing is missed, and by the time the leaf buds have grown too large or leaves have already emerged, cut grafting will not easily survive.

Potting Methods for Wintersweet Bonsai

1. Pot selection: To make wintersweet bonsai, you can choose a purple clay pot with good breathability for planting. Yangguang Nursery Stock Network suggests that the pot shape can be chosen according to the specific form of the tree stump and the different styles of the bonsai. Because its flowers are wax-yellow, it is advisable to choose flower pots in dark colors such as reddish-brown, deep blue, and dark green to form a contrast, and it is not advisable to choose light yellow pots. Although glazed porcelain pots are beautiful, they have poor breathability and easily cause wintersweet root rot, resulting in poor growth or even death of the plant, so they can be used as cachepots.

2. Potting soil: Wintersweet is not strict about soil, but well-drained sandy loam is best. For pot culture, rotted garden soil or leaf mold mixed with 20-30% rice husk ash is commonly used as the growing medium.

3. Planting: Transplanting wintersweet is mostly done in early spring, preferably around early March before and after the new buds sprout on the flowering stems. Generally, oblique planting is suitable, making it easier to take on a dynamic form during styling. Before planting, a shaping and pruning can be carried out, and sufficient base fertilizer can be applied at the bottom of the pot when potting.

Care Techniques for Wintersweet Bonsai

1. Location: Wintersweet bonsai should be placed in a wind-sheltered, sunny spot, avoiding cold wind. In summer, slight shading is needed. In winter, potted plants should be moved indoors to overwinter when the temperature is below 1°C.

2. Watering: Wintersweet is relatively drought-tolerant and is known as the “wintersweet that cannot die of drought,” but it should not be overly dry either. Usually the potting soil can be slightly dry. Water according to “see dry, see wet”: if you do not water, then do not water; if you water, water thoroughly. The dog days are the flower bud formation period, and water must not be lacking. Water once in the morning and once in the evening. When leaves fall after autumn, the potting soil can be on the drier side, watering once every 5-7 days.

3. Fertilizing: Wintersweet likes fertilizer. From April to June, in the early stage of flower bud formation, it is advisable to apply cake fertilizer water once every 10 days. From the end of June to before the dog days, apply a dilute fertilizer water combining nitrogen and phosphorus once a week to promote flower bud formation. During the dog days, apply 1-2 times, and the fertilizer should be light. After autumn, apply just 1 more time. When changing pots, sufficient base fertilizer such as bone meal and bean cake can be applied at the bottom of the pot.

4. Pruning: To make wintersweet have luxuriant branches and abundant flowers year after year, pruning and bud pinching are extremely important. Pruning is generally done between March and June, and stops after August. After flowering each year, the old flowering branches should be shortened immediately, leaving only 15-20 cm at most per branch. After the new branches grow 2-3 pairs of buds, pinch off the terminal bud. Before long, side branches grow again; after they reach 10 cm, pinch the buds once more, repeating this several times until the flower buds are basically formed. Also thin out and prune various crossing branches, parallel branches, overlapping branches, opposite branches, water sprouts, and overly dense or weak branches that affect the beauty of the tree shape. There is a saying in flower lore that “wintersweet does not lack branches,” so wintersweet can be heavily pruned.

5. Repotting: Wintersweet bonsai should be repotted once every 1-2 years, preferably at the end of winter or beginning of spring after the flowers fade. Before repotting, the already sprouted buds can first be removed. After about 5 days, when the latent buds begin to swell, transplant again. When repotting, remove 1B3 of the old soil, cut off rotten roots and dead roots, and trim away overly long old roots. Replace with frost-crumbled pond mud or humus-rich leaf mold, mixed with an appropriate amount of rice husk ash and sandy soil.

6. Pest and disease control: Wintersweet has relatively strong resistance to pests and diseases. Occasionally there are pests such as slug moths, large bagworms, aphids, and scale insects, which can be controlled by spraying 80% dichlorvos at 1500 times dilution or 90% crystalline trichlorfon at 1000-1500 times dilution.

Watering Precautions for Wintersweet Bonsai

1. Weather conditions: Water frequently on sunny days, pay attention to drainage on heavy rainy days, and on light rainy days the water should still be watered thoroughly.

2. Seasonal changes: Summers are hot, so water promptly, once each in the morning and evening. Spring and autumn have more rain, so water appropriately according to conditions. In winter during flowering, it is suitable to water at noon.

3. Soil texture: Clay soil has strong water-holding capacity, humus soil is medium, and sandy soil loses water easily. All should be noted.

4. Pot size, depth, material, drainage holes, etc.: If the pot is small and shallow, made of ceramic, dark-colored, and has unobstructed drainage holes, it dries most easily. Conversely, water retention is stronger.

5. Watering with rainwater, well water, tap water, river pond water: Note that the water temperature should be the same as or close to the potting soil temperature, and also note that the water should not contain acid or alkali.

6. Judging whether the potting soil is dry or wet: This can be judged by leaf color, whether the leaves droop, and the color of the potting soil.

Watering Methods for Wintersweet Bonsai

1. Watering on the leaves: For small areas, use a spray bottle; for large areas, sprinkler irrigation equipment can be used.

2. Watering at the roots: For small areas, use a bucket and ladle; for large areas, use a hose.

3. Drip irrigation: Find a thin water pipe that can control the water flow, such as a disposable infusion tube used in hospitals. Place the bucket higher than the flower pot so that the pipe produces siphon action (or make a small hole in the bottom of the bucket), control the number of drops; generally 20 drops count as one leaf. Watering can be done in fixed amounts daily, and automated management is possible over large areas.

4. Soaking method: Immerse the bonsai together with its pot in water, and take it out after it has absorbed water thoroughly. This can be used for the first watering after potting and for daily watering of miniature bonsai.