(1) The following shall be exempt from the provisions of this article:
(a) The practice of architecture by licensed architects pursuant to part 3 of article 25 of this title;
(b) The practice of professional engineering by registered professional engineers pursuant to part 1 of article 25 of this title;
(c) The practice of professional land surveying by licensed land surveyors pursuant to part 2 of article 25 of this title;
(d) Residential landscape design, consisting of landscape design services for single- and multi-family residential properties of four or fewer units not including common areas;
(e) The design of irrigation systems by professionals qualified by appropriate experience or certification; and
(f) Landscape installation and construction services, including, but not limited to, all contracting services not within the scope of the practice of landscape architecture.
(2) Nothing in this article shall prohibit or limit a municipality or county of this state, in the reasonable exercise of its police power, from adopting codes that may be necessary for the protection of the inhabitants of the municipality or county.
(3) Nothing in this article shall be construed to limit or extend the rights of another profession or craft.
(4) Nothing in this article shall be construed to prohibit the practice of landscape architecture by any employee of the United States government or any bureau, division, or agency of the United States while discharging his or her official duties.