It’s ugly out there right now, but I’m not sure there’s anything specific about our field that makes it any more prone to economic hardships and layoffs than other professions.
What’s happening right now has hit builders, developers and the construction industry in particular very hard. Clients can’t get loans to start/complete projects so the entire industry (including Architecture, Engineering, MEP, etc.) is feeling the pinch, not just residential either. Public municipalities are still spending the money they have, but budgets will shrink for next year as foreclosures rise, and tax bases are reduced.
As for your other questions, assuming good economic times you can make a decent living as a Landscape Architect. Like any design profession, the hours worked are a direct result of client demands and your drive to succeed. All-nighters should be the exception, not the norm, but in my experience (and I’ve only been at this for about 8 years) the best LA’s rarely make it a 9-5 job and are willing to put in some extra effort to ensure a quality and timely product.
Hope that helps.