Wintersweet is a slow-growing shrub that can take as much as 15 years before it reaches flowering maturity. It is normally planted as a container-grown nursery specimen or ball-and-burlap plant in spring or summer. Chimonanthus praecox is sometimes erroneously described as a toxic plant. But this is because it is often confused with another plant also sometimes called wintersweet, Acokanthera spp. But while Acokanthera has well-documented toxicity, C. praecox is not included on any official lists of plants toxic to humans or pets. However, there are documented cases of C. praecox causing toxicity in grazing goats. Once it is planted, mulch the shrub’s root zone to a depth of 3 inches out to the drip line, but take care to keep the mulch material from touching the trunk. This will aid in moisture retention while the plant is watered deeply until it is established—about one full season.
Light
To encourage your wintersweet to produce more blooms, plant it in a location that receives full sun.
Soil
Wintersweet thrives in moist, fertile, well-drained soil. It is not fussy about pH, growing equally well in acidic, neutral, or alkaline soils.
Water
Water generously until established. Once established, regular watering is still needed during the summer and in cases of high temperatures or drought.
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.
Fertilizer
Fertilizer is not needed but can help with flowering. A 5-30-5 liquid fertilizer will help produce more blooms on your wintersweet.
Types of Wintersweet
There are two popular cultivars of C. praecox:
‘Grandiflorus’ offers sweetly-scented blooms and butter-yellow flowers.‘Luteus’ has fragrant flowers and dark-green leaves.
In addition, there is a related species to consider. Chimonanthus nitens’ features evergreen leaves and white flowers but lacks the overpowering scent of C. praecox.
Pruning
With established plants, wintersweet should have seasonal maintenance performed 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 cascade in a natural fashion, so don’t attempt to shape it too strictly.
Propagating Wintersweet
Since wintersweet grown from seed can take nearly 15 years to flower, the best way to propagate wintersweet is by creating stem-cuttings. To do so: Wintersweet can also be propagated by layering—the process of staking down a flexible branch into the soil, waiting for it to develop its own roots at the point of soil contact, then carefully freeing the new root system and stem to plant in another location.
How to Grow Wintersweet From Seed
Mature seeds of wintersweet can be planted in small pots filled with potting mix and placed in an outdoor cold frame to germinate and sprout. But you’ll need to be patient, as seed-sown plants can take 10 years or more before they reach flowering maturity.
Potting and Repotting Wintersweet
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 will need to be positioned in a sheltered location to overwinter. These are slow-growing shrubs, so repotting will be needed 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.
How to Get Wintersweet to Bloom
The bloom time for wintersweet varies a bit, depending on where it is grown. At the northern end of its hardiness range, it typically blooms in February and March, but further south it will bloom in December through January. To encourage wintersweet to bloom, make sure it is adequately fed and watered, and that it gets sufficient sunlight. Yearly pruning will also ensure good blooming. Untimely frost may kill flower buds and cause poor blooming. The shrub generally recovers and will bloom normally the following year. In borderline climates (zones 6 and 7), it helps to plant wintersweet in a spot protected from harsh winter winds.
Common Problems With Wintersweet
This shrub is largely free of cultural problems, but as it ages, wintersweet 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 one-third of all older stems after the flowering period is over. Shortening the remaining stems will also force the plant to become denser. . Juxtaposing wintersweet with winter hazel, some well-placed dwarf conifers, striped bark Japanese maple, or red twig dogwood, makes a stunning statement during the winter.
