I agree with the information provided by Thomas above. Some other technical skills that are helpful to being a landscape designer include:
Software Skills: AutoCAD, LandF/X, GIS, SketchUp, Rhino, Revit, Lumion, Adobe Creative Suite (Photoshop, Illustrator, Indesign), Microsoft Office Suite (Word, Excel, Powerpoint), even hand drafting or drawing (you don't need to be a phenomenal artisit to be a successful drawer or landscape designer)...you don't need to know all of these skills, and will learn most of these when you go through a Bachelors or Masters program, but the more you are familiar with and the more you are exceptional in, the better!
Environmental Skills: Tree Identification, Arboriculture, Horticulture, Biology, Hydrology, Forestry, Irrigation, Landscape Contracting, etc....these are great additional skills and knowledge to be familiar with. Many of these you'll likely take classes on during your education, but through internships, summer jobs, or even through volunteering or as a hobby, you can pick knowledge on many of these subjects that can be very valuable in the job market.
This is a career that requires formal training, education, and licensing.
Education: A landscape architect must earn a Bachelor of Landscape Architecture (BLA) or a Bachelor of Science in Landscape Architecture (BSLA). You'll spend four to five years taking classes in design, construction techniques, art, history, and natural and social sciences to complete either degree. You can also earn a Master of Landscape Architecture (MLA). It will take you two years to complete your MLA if you already have a BLA or BSLA, but otherwise, you'll spend three years in a master-level program.
Training: Training requirements can be state-specific. The Council of Landscape Architectural Registration Boards (CLARB) offers a searchable database of training requirements based on location.
Internships: Entry-level applicants can work as interns under the supervision of licensed architects while completing the licensing process, but this generally isn't required.
Licensing: This is a licensed occupation in all states except Massachusetts, Illinois, and Maine. The exact requirements can vary, but each state requires must pass the Landscape Architect Registration Examination (L.A.R.E.) which is administered by the (CLARB). Other requirements can include having a degree from a program that's been accredited by the Landscape Architecture Accreditation Board of the American Society of Landscape Architects. CLARB maintains a list of all state licensing requirements.
Landscape Architect Skills & Competencies
These soft skills and personal qualities can be essential to your success as a landscape architect:
Active listening: This will allow you to understand your clients' needs and wants.
Verbal communication: You must be able to convey information to your clients.
Creativity: Your creative side will allow you to design beautiful outdoor spaces that are also functional.
Critical thinking: Landscape architects must make decisions and solve problems. Strong critical thinking skills will let you identify possible solutions, then evaluate them before choosing the best one.
Reading comprehension: You must be able to understand work-related documents.
Computer skills: Technology plays a big part in this job, including software like CADD for model preparation and Geographic Information Systems (GIS), so proficiency is required.