Yes, the Jardin Majorelle is probably part of every visit to Marrakech. It's important to know that you have to book your tickets online in advance. Many people didn't know this and then stood around stupidly in the queue only to be sent away at the end.
The garden was then really full. It is dominated by the famous blue colour, but the cacti are particularly worth seeing. There is also a museum about Berber culture, but photography was forbidden there.