Light:

Full to partial sun (southern, eastern or western exposure).  The more sun the better.

Temperature:

Maintain indoor temperatures above 40° for potted plant.

Humidity:

50% or higher; however, they will tolerate low levels with no harm.

Watering:

Bring soil to visual dryness between watering.  When watering, thoroughly saturate soil until a little water runs out of the bottom of the pot.  They are “soft growers” and can use lots of water under high temperature and low humidity.  A slight wilt does no harm.

Fertilizer:

They need heavy to moderate levels of fertilizer.  Give them more under high light.  Under most conditions fertilize with ½ tsp./gallon once a week.  If leaves become pale or older leaves turn yellow and fall excessively, increase fertilizer to twice a week until they green up.  Use a balanced fertilizer i.e. 15-15-15 or a blooming fertilizer like Pro Gro ‘Grow’ 7-9-5 or Electra 5-10-3.

Pruning:

Prune after flowering is complete.  As they are large and rapid growers they periodically need a hard pruning, which they take with ease.

Insects and Disease:

Cestrum are susceptible to whitefly, spider mite and aphids.  They have little susceptibility to diseases of either foliage or roots.

Comments:  

Cestrums are fast and easy growers.  Some, like C. elegans smithii, C. newelii and C. diurnum, flower on the change in day length, so pruning needs to be adjusted so as not to cut off the flowers.  Generally we don’t like to prune the above after the first of June.   C. nocturnum is an everbloomer that flowers on the mature growth.