cassia

[stephen.prout@uk]

i know this is not a cactus but my cassia are multing and im not sure whats happening to them the lower leaves are yellowing and falling they germinated this year there both about 2 1/2 -3 ft tall is this normalthey also dry out pritty quick because there in my green house and its summer and i dont keep on the watering very well can any one put my mind to rest.