Chimonanthus

( kye - moh - NANTH - us )

At-A-Glance Information

Wintersweet and Japanese Allspice are the common names for these deciduous shrubs, which need moderate water and afternoon shade in the hottest climates. The genus name is derived from the Greek words for winter (cheimon) and flower (anthus). There is only one species, Chionanthus praecox, that is commonly cultivated in home gardens. Blossoms on these shrubs are spicy-scented and appear on leafless branches in late winter or early spring. Blooms last for about a month until the frost kills them off. These shrubs have an open growth habit and can reach 10-15 feet tall and 6-8 feet wide at maturity. Green leaves will turn yellow in fall. Wintersweet grows best in USDA hardiness zones 6-9 or Sunset growing zones 4-9 and 14-21 (to find your zone, click here: Zone Map). Take care when planting these shrubs in the landscape, as ingestion of plant parts (especially seeds and flowers) can cause severe toxicity symptoms.

Caring for chimonanthus

The best way to grow a Wintersweet shrub is from a nursery specimen; those grown from cutting or seed take a long time to mature, and can take up to 15 years to flower. Nursery plants will take about a year to be established and begin flowering. Space plants about 10 feet apart for best coverage and airflow. Wintersweet grows best in soils that are loamy or sandy, but will also adapt to amended clay conditions. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 6.0 and 8.0 (slightly acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Wintersweet also prefers full sun conditions, but in warmer climates will need some afternoon dappled shade to perform well. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Wintersweet shrubs are considered to be somewhat drought-tolerant, but perform best when they receive regular waterings, especially during spring and summertime.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Yearly after blooms fade, cut old wood down to a foot or less in height. This will rejuvenate the plant for the coming year. Don't attempt to control the habit of this plant via pruning; it is best when left to its own devices, and its natural form has a very pleasing, cascading nature. These shrubs will only bloom on old wood (growth from the previous ear), and flower buds are set in summer or fall. Take care to not prune after late spring or early summertime to avoid removing next year's early-season show of flowers. Chimonanthus shrubs can persist for an average of 10-15 years in the landscape before needing to be replaced, and take about decade to reach their full, mature size.

Propagation

Wintersweet can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. Also note that Wintersweet will take between 5-15 years before flowering if grown from seed. To propagate your Wintersweet shrub, follow the instructions below:

Propagating Chimonanthus by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. In July or August, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home.
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​Propagating Chimonanthus by Seed
  1. Keep in mind that the shrub you get from seed will not necessarily mimic all of the characteristics of the parent plant (ant that it will take a while to bloom - as much as 15 years). To propagate by seed, you will need a paper envelope, a paper towel, a sealable container, a bowl, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. Harvest your seeds. The seed pods on these plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. Wintersweet seeds will need a period of cold-stratification in order to germinate. Place seeds in lukewarm water for two hours and then remove them, placing them in a damp paper towel. Put the towel in a plastic sealable bag, and then put it in a warm, dark location for three days. Remove the seeds from the plastic bag and paper towel, allow them to dry out, and then place them in an envelope in a sealed container. Place the container in your refrigerator for 5-8 weeks.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in an area that receives bright, indirect light and stays around 55 degrees Fahrenheit.. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 60 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring or early summer (after the danger of frost has passed), when you can transplant it to its new home in your garden.
Wintersweet seed pods are left behind after the shrub's flowers have faded. They contain one to three seeds each.
Chimonanthus seeds are small, brown, and elliptical.
​They are toxic.

Problems and Pests

Chimonanthus, or Wintersweet, shrubs can be affected by the following issues in the landscape:
  • Scale
  • Grasshopper Cicada
For more information about these pests and diseases, including how to identify and eradicate them, see the links below:
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Gallery

Plant Wintersweet shrubs near doorways or walkways, where their flowers' color and fragrance can be admired close-up.
Wintersweet blooms when many other plants are dormant - making them a great focal point for gardens in early winter.
The foliage of Chimonanthus is green for much of the year, turning yellow in the cooler temperatures of fall.

Videos

An introductory video to the species.
How to identify a Wintersweet shrub.
A short video about Chimonanthus praecox.
An informative video about Wintersweet.

Resources

Common Pests and Control Methods of Chimonanthus praecox
How to Grow and Care for Wintersweet
OSU: Chimonanthus praecox
Chimonanthus praecox
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 239 - 240, Chimonanthus praecox