Sweet box, or Sarcococca, is a small group of shade-loving evergreen shrubs grown less for their looks than for flowers you smell long before you see them. They open in winter, and the scent is far bigger than the plant. Plant sweet box beside a door, gate, or path you walk in winter, since that is when the flowers open. The kinds sold under the name differ mostly in how tall and spreading they grow, from 6-inch mats to 6-foot shrubs, and in whether their berries end up black or purple. Labels are an unreliable guide, because breeders have selected dwarf forms of even the tall kinds.
How Many Kinds of Sarcococca There Are
In the wild, sarcococca grows from Afghanistan through the Himalaya into China, south through India and Sri Lanka, and east to Java, Sumatra, Taiwan and the Philippines.1Botanical Journal of the Linnean Society. A revision of the genus Sarcococca (Buxaceae) Botanists accept 11 species in the group.2Oxford Academic. A revision of the genus Sarcococca (Buxaceae) Some of those species are split into varieties (abbreviated var.), which are naturally occurring forms of one species that differ in looks, such as height.3Oxford Academic. A revision of the genus Sarcococca (Buxaceae) So one species may come in a tall form and a short form under the same name.
Most nurseries sell S. hookeriana and S. confusa, and sometimes S. saligna or S. ruscifolia. The other species are rarely sold outside botanic gardens. The common names sweet box and Christmas box cover all of them, so the full Latin name on the tag is what tells you what you bought.
Sweet box belongs to the same family as boxwood.4Trees and Shrubs Online. Sarcococca The two are easy to confuse at a glance, but sweet box leaves alternate along the stem, while boxwood leaves sit in opposite pairs.5Trees and Shrubs Online. Sarcococca The relationship matters in practice because the two share some diseases, covered later.
A full tag name has the genus, the species, and sometimes a variety or a quoted named selection, for example Sarcococca hookeriana var. humilis ‘Sarsid1’. If the tag says only “sweet box” or “Christmas box,” you can’t know the eventual size, so ask the seller or look up the species before buying. When size matters in a tight spot, trust a named selection with a known height over a bare species name.
Sarcococca Hookeriana and Its Low-Growing Forms
Sarcococca hookeriana, native from central China to Tibet, is probably the most widely grown species.6Juniper Level Botanic Garden. Christmas boxes through the Garden Its variety digyna can reach 5 feet, while variety humilis tops out at about 2 feet.7Juniper Level Botanic Garden. Christmas boxes through the Garden Humilis forms a dense, ground-hugging mat suited to mass planting under trees and shrubs.8Gardenia. Sarcococca hookeriana Digyna is known for arching stems and pink-tinged winter flowers.9Gardenia. Sarcococca hookeriana Most commercial selections of both varieties are dwarf forms, so height won’t tell you which variety you have.10Juniper Level Botanic Garden. Christmas boxes through the Garden
A named selection is a plant picked out by a grower for a useful trait and then kept going by propagation. The trait might be a compact size, a stem color, or a flower look, and it is the reason the plant has its own quoted name. Because named selections are propagated from the original, plants with the same name should look and grow alike, unlike seed-grown plants. A selection sits under a species or variety, so read its label together with that parent name.
- ‘Sarsid1’ (humilis): the most compact form seen at one garden, a mat about 6 inches tall.11Juniper Level Botanic Garden. Christmas boxes through the Garden
- ‘Purple Stem’ (digyna): from Hilliers Nursery in the UK, with purple young stems, forming a 4-foot-wide patch of 18-inch stems after 10 years.12Juniper Level Botanic Garden. Christmas boxes through the Garden
- ‘Winter Gem’: a hybrid of the two varieties bred by Peter Moore in the UK.13Juniper Level Botanic Garden. Christmas boxes through the Garden
- SWEET & LO ‘Purplerij1’: red-tipped white flowers with a jasmine-like scent in late winter to early spring.14Plant Finder. SWEET & LOâ„¢ Sarcococca hookeriana ‘Purplerij1’
To cover ground under trees, pick humilis or ‘Sarsid1’. For a knee-high clump in a border, an arching digyna type such as ‘Purple Stem’ does the job. Spread is slow, and ‘Purple Stem’ took a decade to reach 4 feet wide, so don’t expect quick cover. Space each plant by the width it will reach, not by the size of the pot.
Labels for ‘Purple Stem’ often conflict: some sellers list it under digyna, others under var. hookeriana. If size matters, buy from a nursery that names the variety.
Sarcococca Confusa, Saligna and Ruscifolia
Sarcococca confusa is a bushy evergreen to about 2 meters (6.5 feet) with glossy, wavy leaves 3 to 5 cm long.15RHS. Sarcococca confusa Its small creamy-white flowers smell very sweet, often described as honey or vanilla.16RHS. Sarcococca confusa17Garden Nursery. Sarcococca confusa Sweet Box The berries start shiny red and turn black, often lasting through winter.18North Carolina Extension Gardener Plant Toolbox. Sarcococca confusa
At the nursery, confusa has short, broad, glossy leaves with a slightly wavy edge, while hookeriana leaves are more slender. Confusa grows as an upright bush, while hookeriana tends to form a spreading clump or mat. Both end with black berries, so berries alone won’t separate them. Because confusa gets taller and bushier, it works as a low hedge along a shady path, where the low forms would not.
Sarcococca saligna grows to about 1 meter and spreads by underground shoots.19Royal Horticultural Society. Sarcococca saligna Its leaves are lance-shaped and up to 13 cm long, on upright then arching stems.20Royal Horticultural Society. Sarcococca saligna Its greenish-white flowers are only slightly scented, followed by purple berries.21Royal Horticultural Society. Sarcococca saligna If fragrance is your main goal, choose another species.
Where Sweet Box Grows Best
Sweet box prefers full to partial shade.22NC State Extension Plants. Sarcococca confusa It likes moist, humus-rich, well-drained soil, neutral to slightly acidic.23Gardenia. Sarcococca hookeriana It copes with clay improved with organic matter and with tree-root competition.24Gardenia. Sarcococca hookeriana Waterlogged soil, though, invites root and stem rot.25Heligan Shop. Sarcococca confusa Full sun can yellow or scorch the leaves, and north or east walls suit it well.
To plant, dig a hole a bit wider than the pot and mix compost into the soil you put back, especially if your soil is heavy clay. Set the plant at the same depth it grew in the pot, with the top of the root ball level with the ground, because burying the stem base invites rot. Spread mulch around the plant but keep it off the stems. It holds moisture, particularly under trees where roots compete.
Keep new plants evenly moist the first year.26Gardenia. Sarcococca hookeriana Water weekly during dry spells so the roots can establish. Once established, it tolerates drought when grown in shade.27NC State Extension Plants. Sarcococca confusa Growth is slow to moderate.
Confusa is hardy in US zones 6 through 9.28NC State Extension Plants. Sarcococca confusa A hardiness zone is a map band based on a region’s typical coldest winter temperatures. Saligna is rated hardy to about -10 to -5°C, through most of the UK.29Royal Horticultural Society. Sarcococca saligna Sweet box also resists deer and rabbits and tolerates pollution.30NC State Extension Plants. Sarcococca confusa
Pests and Diseases to Watch For
The fungi that cause box blight attack most boxwood and can also infect sweet box, which is somewhat susceptible.31RHS Advice. Box Blight: Prevention Tips Avoid planting it right beside blighted boxwood. Blight shows as brown leaf spots and dropping leaves, so check plants near any boxwood.
Scale insects feed on sap and weaken plants over time.32Greenwood Plants. Plant Focus: Sarcococca They look like small bumps on the undersides of leaves and along stems, and sticky leaves can be a sign of them, since the insects leave a sugary residue. Cut off and dispose of affected leaves to stop spread.33Greenwood Plants. Plant Focus: Sarcococca You can also scrape scale off by hand or use horticultural oil.34Heligan Shop. Sarcococca confusa Put infected material in the bin rather than the compost heap.
Space plants for airflow, water at the base rather than overhead, and check new plants before planting. If you also grow boxwood, clean your pruners between it and sweet box.
Growing More Sweet Box From Cuttings
Semi-hardwood confusa cuttings taken in February and set in perlite began rooting after about 23 days.35Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi. Sarcococca confusa Çeliklerinin Köklenmesi Üzerine Farklı IBA Dozlarının Etkileri With rooting hormone, cuttings can reach full rooting within 12 weeks.36Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi. Sarcococca confusa Çeliklerinin Köklenmesi Üzerine Farklı IBA Dozlarının Etkileri Hormone treatment produced more and longer roots than none.37Iğdır Üniversitesi Fen Bilimleri Enstitüsü Dergisi. Sarcococca confusa Çeliklerinin Köklenmesi Üzerine Farklı IBA Dozlarının Etkileri
In late winter, cut a firm shoot 10 to 15 cm long from the previous season’s growth that is no longer soft. Strip the lower leaves, then dip the cut end in rooting powder. Insert it in perlite or a gritty mix and keep it humid, out of direct sun. Pot it up once roots have formed, which can take weeks, so don’t pull on the cutting to check.
Kinds that spread underground, such as humilis and saligna, can also be divided. In spring, dig a rooted clump at the edge of the patch, replant it at once, and water well.