The rare Cestrum buxifolium was discovered in cloud forests of the Andes mountains in Venezuela.  It is an attractive bush that blooms throughout the year, with lovely purple-burgundy tubes tipped with creamy, star-shaped petals that flare outwards.  The plant is new to cultivation, and deserves to become very popular.  I don't know anyone in the US offering it.

  Cestrum buxifolium is an evergreen shrub that grows about 6 feet tall and wide, although you may prune it to any size you wish.  Its glossy foliage is unusually small for Cestrums, resembling those of a Boxwood, hence the species name.  The plant blooms in waves about every 2 months during the year, including winter.  The inch-long flowers emerge in large, radiating clusters at the ends of the branches.  The flower color varies depending on the season, with the winter blooms having a darker tube color and whiter petals (photos 2 & 4).  After flowering, it makes purplish-black berries that will stain your fingers purple!

It comes from higher elevations, where the climate is mild all year, and nights are cool.  I have no information on how much heat it can take, so consider it experimental in areas that regularly get above 85 degrees F (29°C) and nights are warm (above 65°F / 18°C).  I don't know its frost tolerance.  It might only be hardy to 25-30° F (-3°C).  It flowers best in mostly-sunny conditions, but some afternoon shade might be needed in warmer climates.  It grows well in a container in well-draining soil that's kept evenly moist.  Avoid letting it dry out completely.  The leaves and fruit of some Cestrums contain a toxin, so it's best to keep pets and small children away from the plant.