A specialist in gardening or landscaping is who you hire to do the job. They can be self taught, a Master Gardener, certified nurseryman, horticulturist, landscape engineer, or combination of any of these.
Horticulturalist.
A horticulturalist is a specialist in gardening. A handyman is a person that may do various gardening and landscape chores.
The best thing to do is to try and avoid damaging your garden while landscaping. It is not as hard as it seems.
William Flemer has written: 'Nature's guide to successful gardening and landscaping' -- subject(s): Landscape gardening, Gardening
Horticulture
Mixing concrete for construction, landscaping, gardening
You question is confusing. Horticulturists are the best people to give advice in gardening. I would assume from your qustion shoulod read "who would be the one..."? Answer Horticulturists are learned people with college training they will give you the theory. If you want good practical advice ask a gardener.
The Sunset Western Landscaping book is one of the best landscaping books to hit the market. There is a lot of information in it.
Jo Kellum has written: 'Landscaping 1-2-3' -- subject(s): Landscape gardening, Landscape plants 'Southern shade' -- subject(s): Selection, Shade-tolerant plants, Gardening in the shade 'Landscaping 1-2-3' -- subject(s): Landscape gardening, Handbooks, manuals, Landscape design 'Ortho's all about shade gardening' -- subject(s): Gardening in the shade, Shade-tolerant plants
Alison P Kelly has written: 'Gardening' -- subject(s): Bibliography, Gardening, Natural landscaping, Native plants for cultivation
Muriel Orans has written: 'Houseplants and indoor landscaping' -- subject(s): House plants, Indoor gardening 'Houseplants & Indoor Landscaping (Countryside books)'