Gardens

Plant of the Month: February

Chimonanthus praecox Common name: Wintersweet, Japan all-spice Family: Calycanthaceae Vital statistics Height and spread: 4m by 4m (12ft by 12ft) Form: Deciduous shrub Soil: Fertile, well-drained soil. Aspect: Full sun, sheltered from cold, drying winds. Hardiness: Fully hardy in the British Isles, young growth may be subject to frost damage.

Chimonathus praecox @ Wisley

There are examples of Chimonanthus praecox around the Garden at Wisley, for example, on Battleston Hill, but the best specimen is of C. praecox 'Grandiflorus', found in the Canal Borders, beside the path that leads to the toilets in front of the Laboratory.

Chimonanthus

This group consists of six evergreen and deciduous shrubs native to cliffs, glens and gorges of China, though only one, C. praecox, is usually grown. These shrubs, commonly known as wintersweet, produce very fragrant, waxy flowers in the winter.

C. praecox is a medium-sized, deciduous shrub that produces waxy, light yellow flowers with purple centres. The flowers, which aren't produced on young plants, are extremely fragrant and are the main reason for the cultivation of this plant.

Chimonanthus praecox

Chimonanthus praecox is a multi-stemmed shrub with a fountain-like shape. When mature it can reach a height and spread of about 3m (10ft), and they look excellent as specimen plants or in a shrub border, and can also be trained effectively against walls.  The name is derived from the Greek cheimon meaning winter and anthos flower. Praecox is from the Latin meaning very early.

The flowers are pendent, yellow, and cup-shaped with almost translucent waxy petals.  They usually have reddish brown or even purple centres, and adorn bare branches in winter before the leaves emerge in spring. The flowers are exceptionally fragrant and just a few cut stems can fill a room with fragrance. The scent is like jonquil and violets, but when the fragrance is inhaled close to for any length of time the smell seems to disappear.

Five to eight shiny brown fruits are held within an urn-shaped receptacle, but are not particularly ornamental.  They set by April, can be harvested and sown by late May, but will persist on the plant through the following winter.

The flowers are used in pot-pourri and to make perfumes, and have some limited edible uses.  The petals are used to flavour and scent tea, and if boiled and washed they can be eaten with oil and salt!

After soaking the wood in water it can be polished to produce a brilliant black finish.

C. praecox 'Grandiflorus' has larger deep yellow flowers, up to 4.5cm (1.75in) long, with conspicuous maroon markings inside.  C. praecox var. luteus (syn. 'Concolor', 'Luteus') has blooms that are a purer, paler yellow which open widely, and cheer up the dullest of corners. 

AGM

The RHS Floral B Committee awarded Chimonanthus praecox 'Grandiflorus' an Award of Garden Merit and described it as:

Bushy deciduous medium-sized shrub, with shiny lanceolate leaves to 15cm long. Flowers small, highly fragrant, waxy yellow with maroon centre.

The RHS Floral B Committee awarded Chimonanthus praecox var. luteus an Award of Garden Merit and described it as:

Medium-sized, bushy deciduous shrub. Leaves to 12cm, glossy, lanceolate; flowers small, waxy yellow, highly fragrant.

The RHS Floral B Committee awarded Chimonanthus praecox 'Margaret Best' an Award of Merit and described it as follows:

C. praecox is a well-known, deciduous, sweetly scented, winter flowering shrub to about 3m in height, introduced into cultivation in this country from China in 1766. When grown from seed, there is a variation in flower colour and size. In this cultivar, the flowers were paler than those of the two named cultivars `Luteus' and `Grandiflorus' more usually grown in gardens. Each solitary flower of 2.5 to 3cm in diameter is produced on a very short pedicel with a number of pale brown papery scales. The clawed tepals are in three whorls, the inner 5 or 6 almost erect to 11 x 5mm, translucent, strongly suffused with deep maroon 187A-B, the central whorl more-or-less translucent but faintly tinged yellow 3B-4A spreading to 13 x 4mm slightly streaked with maroon at the base and the outer tepals similar in colour but longer to 14 x 4mm and without maroon streaks at the base.

Cultivation

Chimonanthus can be grown in any well­-drained, preferably loamy soil in a sunny sheltered position. Badly drained or compacted soils may cause blotching or yellowing of the leaves. It will succeed in most soils but it seems most at home in chalky ones. It is hardy to about -25°C, but to induce heavier flowering and ripen the new growth, it is best grown on a sunny wall.

Plants take from five to 12 years to flower from seed. The cultivar 'Grandiflorus' may come true from seed and has larger flowers than the type.

Plants flower profusely when established and left unpruned, and if any pruning is necessary then it is best done immediately after flowering, especially if wall trained. The flowers are produced in the leaf axils of wood three to four years old. With age, it can become quite leggy and ragged.  It can be pruned to within 15-30cm (6-12in) of the ground in late winter to rejuvenate it.  Generally little pruning is required when grown in the garden.

Chimonanthus is notably resistant to honey fungus.

Propagation

Seed is best sown in containers in a cold frame as soon as it is ripe. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.

Softwood cuttings can be rooted in July and August, although it has a reputation for being difficult to succeed. Alternatively propagate by layering in either spring, or July or August.  It should take about nine months but has a better success rate than taking cuttings.