Answer : It depends. Typically it's not that stressful, but there are also a number of stressors such as time pressure.
Landscape architecture is fairly low-stress because the profession is so infrequent in terms of competition and people who practice it. Landscape architects place an emphasis on sustainability and innovation which helps them feel in control of their careers and lives. However, the job does present many other challenges including high responsibility combined with high risk factors - all this can lead to a stressful work environment for landscape architects.