White-flowering trees add an elegant, sophisticated element to the garden. Those that bloom in winter, the months of December, January or February are limited in temperate-zoned regions, but are more numerous in the mild climates of the tropics. Glass conservatory or large atrium facilities are the best places in cold winter regions to enjoy a broader display of winter-flowering trees.
In the Northern Hemisphere, winter is defined by the southern-most angle of the sun on the winter solstice, in late December. In the garden, the months of December, January and February are usually considered winter, even though in some climates the cold can last much longer.
In the tropics, there are only wet and dry seasons. "Winter" here usually correlates to the dry season, when warm, weaker intensity sunlit days occur with cool but comfortable nights. Lower humidity and a lack of daily, consistent thunderstorm rains prevails.
In the Southern Hemisphere the seasons are reversed, so that "winter" would be defined as the months of June, July and August.
Temperate Region Trees
In cold winter regions across the Northern Hemisphere, very few trees with flowers occur from December through February, often flowering better in the slightly warmer times of early spring in March. In the mild winter areas of the temperate zone, however, one tree in particular is known to flower in January and February, the Japanese apricot (Prunus mume). Normally blooming in shades of coral pink, white-flowering selections include cultivars Alba, Viridicalyx and Albo-Plena.
Other winter-flowering plants that can attain tree-like shapes and proportions that have white blossoms include some varieties of camellia (Camellia japonica, Camellia oleifera or Camellia reticulata), fragrant teaolive (Osmanthus fragrans), strawberry tree (Arbutus unedo) and loquat (Eriobotrya japonica). The hardiness of these plants varies, but most cannot handle winter temperatures below 0 to 15 degrees F, and prolonged winter cold can delay blooming.
White sunlight intensity may be less during the dry or "winter" season in the tropics, there are some trees that naturally flower this time of year. Some plants also can be flushed into flower after a pronounced rainfall event during this, the dry season.
Orchid trees (Bauhinia semla, Bauhinia variegata "Candida" and "Alba") are known to flower anytime from late autumn through to early spring. Cape chestnut (Calodendron capense) has pinkish flowers that are so pale as to look white. Wilga (Geijera parviflora) and paperbarks (Melaleuca spp.), mostly Australian natives, bear lots of tiny white flowers in winter. Balsawood (Ochroma pyramidalis) bear magnolia-like blooms beginning in winter and continue to summer. Victorian box (Pittosporum undulatum) blooms with small fragrant blossoms in late winter. Loquats (Eriobotrya japonica) also bloom in winter.
Tropical trees that bloom year round and can include a display in the heart of winter include lechoso (Stemmadenia littoralis), China doll (Radermachera gigantea), guava (Psidium guajava), shaving brush tree (Pseudobombax ellipticum var. album) and tree lily (Portlandia spp.). Winter blooming occurs only if temperatures are mild and usually accompanied by a warm rain.