Warm Group Brugmansia
Brugmansia aurea comes from the Andes region from Ecuador, Colombia and Venezuela. It occurs at higher altitude than other “warm group” species, from 2000 to 3000 metres, and is thus adapted to cooler temperatures, but it is nevertheless highly sensitive to frost.
It is very strong-growing and has the largest leaves of all brugmansias. It is very variable in leaf shape, colour, and hairiness. The nodding to horizontal flowers are also variable in size and colour, including pink, white, yellow and orange examples. Not only is it very variable, but it also intergrades with B. ? candida (of which it is a parent), sometimes making difficult distinguishing non-hybrid B. aurea from hybrids.
The calyx covers the narrow part of the corolla tube, and its tip is usually divided into five segments. It has the longest petal tips (‘tendrils’) of all Brugmansia species. The corollas generally have a rather firm waxy texture, useful in hybridising with flimsier-flowered species. The seedpods of B. aurea are egg-shaped. The seeds are the largest of all the species and are covered by a thick, corky, angular seed coat.
Brugmansia suaveolens occurs along the Atlantic coastal rain-forested region of eastern Brazil, and is thus widely separated from all other Brugmansia species which are found in the tropical Andes. It was the first species to be successfully introduced to cultivation in Europe, in about 1780, from where it soon spread around the world.
The corollas are funnel-shaped and nodding, with very short petal tips, variable in colour including white, yellow and pink. Like the similar B. insignis, they actively open and close depending on the time of day. The leaves are mid-green and untoothed. The calyx is usually toothed at the tip and the narrow part of the corolla tube usually extends beyond it.
The seed pods are smooth and spindle-shaped, usually with the persistent calyx covering the upper portion. Seeds are more or less flattened but with an ornamented corky covering.
Brugmansia versicolor is restricted to a relatively small area of southwestern Ecuador on the western slopes of the Andes at rather low altitude, up to about 750 metres. It is quite sensitive to cool temperatures.
This species has the longest flowers of all brugmansias, reaching as much as half a metre (excluding the stalk), though most examples are rather shorter. They always hang vertically. The calyx is slender, pointed and slit only once. The narrow part of the corolla tube is characteristically visible extending from the mouth of the calyx. The flowers are white, pink or apricot and, if coloured, they open white and then colour overnight. The corollas typically wilt during the day and are rather easily scorched in hot dry weather.
The seedpods are very long and slender, containing somewhat flattened, ornamented seeds with a fairly thin cork covering.
Brugmansia versicolor is a parent of the hybrid B. x candida, with which it intergrades in parts of Ecuador.
Botanically named hybrids
Brugmansia x candida is the hybrid of B. aurea and B. versicolor. It includes all hybrids between these species – not only first generation crosses, but also back crosses to the parent species, and crosses between different B. x candida. It is thus very variable and can range in appearance anywhere between the two parent species. Although named in 1805, it was not until the late 1960s that it was discovered to be a hybrid.
It is very widespread, but particularly abundant and variable in Ecuador, and has wider ecological tolerance (particularly with regard to temperature) than either of its parents. Flower colours include white, cream, yellow, pink, orange and apricot.
A mutant form of B. x candida with white double flowers, perhaps originating in Chile, was raised in England in the early 1840s and called “Brugmansia knightii”. It is the ancestor of nearly all the modern double-flowered cultivars.
Brugmansia x cubensis is the hybrid of all three of B. aurea, B. versicolor and B. suaveolens in any combination. It is more variable even than B. x candida, varying anywhere between the parent species. It was first named for spontaneous hybrids between B. x candida and B. suaveolens found in Cuba in the 1970s. The majority of contemporary warm group cultivars are this hybrid.
Various other hybrid combinations of warm group species are possible, but have no botanical names.
Brugmansia insignis is predominantly found in gardens in the Andean foothills of western Amazonia where it is an important plant in indigenous medicine and rituals.
It is very variable in leaf, ranging from very dark green, very narrow and almost willow-like to lighter green and broadly elliptic in shape. The pink or white flowers are funnel-shaped and closely resemble the East Brazilian B. suaveolens except that the corolla neck is usually (but not always) very long, and the petal tips are extended into thin filamentous points. The fruit is always rough, grooved, strongly leathery and spindle-shaped, in contrast to the smoother spindle-shaped fruits of B. suaveolens.
This species is very seldom seen outside northwestern South America, and has been little used in hybridising programs, except for a few examples from the Herrenhäuser Gärten in Germany, such as ‘Pride of Hannover’ and ‘Pink Favorite’. A number of hybrids have been distributed as “Insignis Pink”, “Insignis Gold” etc, but it is unlikely that any of these are actually from B. insignis. Brugmansia insignis was long thought to be a hybrid, but this myth has been dispelled by breeding experiments carried out in Germany and Ecuador.