We have a 20+ yr. old euphorbia trigona that has gotten very brown and woodlike on the bottom third (its about six feet tall). Ineed some advice about what to do about this problem. Thanks.
Sounds perfectly normal for a specimen of that age. http://upload.wikimedia.org/wikiped..._-_LZ-2-LZ-706_-_Euphorbia_trigona_02_ies.jpg