It is. Construction is essentially creating something with functional purposes. That functionality is relevant to each trade. Windows keep water out. Roofing keeps us dry. Electrical brings us power. Everyone required to take part in that process, is involved in "construction", even remotely. More to the point of your question, though, landscaping is constructing a functional part of the project, and is vital for drainage and erosion control. Ultimately...landscaping helps keep the building stand up, by keeping the soil around and under the building from eroding.