Wintersweet is a modest, little shrub that is full of surprises. It shrugs its way through the normal growing season with only green foliage as an ornament. In the middle of winter, it bursts into bloom and fills the garden with its honeyed fragrance. If you are considering putting wintersweet in the landscape and want some tips on wintersweet plant care, read on.
I. Appearance and Characteristics
Chimonanthus praecox, also known as wintersweet and Japanese allspice, is a species of flowering plant in the genus Chimonanthus of the family Calycanthaceae, native to China. The plant is known as là méi (è Ÿæ¢…) in Chinese. The plant is also grown in Iran, where it is called gol-e yakh (گل‌یخ) or “ice flower” in Persian.
It is a vigorous deciduous shrub growing to 4 m (13 ft) tall with an erect trunk and leaves 5–29 cm (2–11 in) long and 2–12 cm (1–5 in) broad. Its strongly scented pendant flowers, produced in winter (between November and March in UK,) on bare stems, have 15-21 yellow or pale green-yellow petals, the inner ones usually with purplish red pigments.
This plant is cultivated in gardens, producing valued flower colour in the dormant season. The cultivars C. praecox ‘Grandiflorus’ and C. praecox ‘Luteus’ have gained the Royal Horticultural Society’s Award of Garden Merit.
The plant is not closely related to allspice, Pimenta dioica.
II. How to Grow and Care
Sunlight
To encourage your wintersweet to produce more blooms, plant it in a location that receives full sun.
Temperature and Humidity
Wintersweet is hardy in USDA zones 7 to 9, although there are cases of it growing in zone 6 in protected areas.
Watering
Water deeply and regularly until established. Once established, regular rainfall will usually fulfill the shrub’s needs. However, you can still water deeply but somewhat infrequently to avoid overwatering. Water more frequently during the summer and in cases of high temperatures or drought.
Soil
Wintersweet thrives in moist, fertile, well-drained soil. It is not fussy about pH, growing equally well in acidic, neutral, or alkaline soils.
Fertilizing
Fertilizer is not needed but can help with flowering. A 5-30-5 liquid fertilizer will help produce more blooms on your wintersweet. Follow product instructions for the correct application amount and process.
Planting Instructions
The ideal location for wintersweet is in a sunny spot sheltered from the wind. The soil should be deep, well-draining and nutrient-rich. As far as the pH value is concerned, the plants are surprisingly tolerant and adaptable, but prefer neutral to chalky soils. If you buy young plants, transplant them into their final location from spring to autumn, with spring being considered the optimal planting time. This gives the young shrubs enough time to take root before the next winter and flowering season.
How to plant wintersweet in the garden:
- Choose a sunny, sheltered location.
- Dig a hole at least twice the size of the root ball.
- Follow steps to improve the soil: In clayey soils prone to waterlogging, add 30% expanded clay or sand to loosen the soil. As wintersweet is a vigorous grower, a little garden compost or pre-fertilised soil such as our Plantura Organic All Purpose Compost will also improve the growth of the young plant.
- Next, place the plant in the planting hole. The surface of the root ball should be level with the surface of the soil.
- Fill the rest of the planting hole with a mixture of soil, potting compost and possibly sand until the soil ball is lightly covered with soil. Then press everything down well.
- Water the shrub and ensure a continuous water supply for the shrub during the growing season.
Pruning
With established plants, wintersweet has seasonal maintenance needs each winter after the blooms have fallen off. The shrub’s oldest stems should be cut down to almost ground level to ensure new, healthy growth during the coming year. This will help to bolster the number of flowers that come on next winter’s stems and keep the shrub at a manageable size and in good health. This shrub looks best if allowed to naturally cascade, so don’t attempt to shape it too strictly.
Propagation
Since wintersweet grown from seed can take nearly 15 years to flower, the best way to propagate wintersweet is by creating stem cuttings or layering.
For stem cuttings, take these steps:
- Using clean, sharp garden shears, create cuttings by snipping off 5-inch lengths, about 2 inches below a flower node on a healthy softwood stem.
- Dip the end of the cutting in the rooting hormone.
- Place each stem into a terra-cotta pot filled with seed-starting mix, right up to the nodes. Keep moist.
- Within about six weeks, you should notice roots. When the cuttings are solidly rooted, transplant them into the garden.
For layering, take these steps:
- Bend down a stem until the middle of it hits the ground.
- Secure the flexible branch down into the soil (so the soil covers it) using a U-shaped pin.
- Place the other loose end of the stem vertically in the soil and stake it into place for stability.
- Wait for both parts or one part to develop roots.
- Carefully free the new root system and stem to plant in another location or leave in place to extend the shrub’s coverage.
How to Grow from Seed
Mature seeds of wintersweet can be planted in small pots.
- Fill pots with potting mix.
- Place pots in an outdoor cold frame to germinate and sprout.
- Be patient. Seed-sown wintersweet plants can take 10 to 15 years or more before they reach flowering maturity.
Potting and Repotting
Though not common, container culture is possible for these plants, especially in their early years before they grow to an unwieldy size. A large, well-draining container filled with standard potting mix will serve adequately but potted plants need to be positioned in a sheltered location to overwinter. These are slow-growing shrubs, so repotting is necessary only every few years when the plant becomes root-bound in its container.
Overwintering
Young plants may require some winter protection against cold, in the form of a thick layer of mulch over the root zone, and possibly a shield of burlap in zones 6 and 7. After two or three years, the shrub should be mature enough to no longer need this winter protection, even in freezing temperatures.
Pests and Diseases
This shrub is largely free of pests, diseases, and other cultural problems. But be on the lookout for signs of distress.
Sparse and Leggy
As wintersweet ages, it may become somewhat sparse and leggy, and often too large for its space. If this happens, perform a severe rejuvenation pruning by eliminating as much as a third of all older stems after the flowering period is over. Shortening the remaining stems will also force the plant to become denser.
Wilting and Yellowing Leaves
Although wintersweet loves water, too much watering can make leaves turn yellow, wilt, and fall off. Stems will also feel mushy if the shrub is overwatered.
III. The most beautiful varieties
The entire family of the sweetshrubs or spicebushes (Calycanthaceae) contains just ten known species. This includes the small handful of wintersweet varieties. Nevertheless, we would like to introduce you to two of them that are commonly found in garden centers.
- Chimonanthus praecox ‘Grandiflorus’: As the name suggests, this variety is characterized by particularly large flowers. In terms of growth and winter hardiness, however, the ‘Grandiflorus’ is comparable to the wild form of Chimonanthus praecox.
- Chimonanthus praecox ‘Luteus’: This variety also only differs from the wild type in its flowers. ‘Luteus’ flowers are a particularly intense yellow.
IV. Uses and Benefits
- Cultural use
C. praecox is a common motif in traditional Persian poetry, literature, and music. A more modern example of C. praecox in Persian music is Kourosh Yaghmaei’s Gol-e Yakh.
- Ornamental uses:
Plant wintersweet in an area where the fragrance can be enjoyed, such as along a path, by a door, or around a gateway. The yellow blooms look stunning when backlit by the winter sun. Wintersweet also makes a good specimen shrub for open gardens or shrub borders, and it makes a beautiful addition to winter-interest Japanese gardens.
