Extension can help farmers with aspects of land and crop/livestock management in terms of agriculture, but if you are referring to horticulture (the care of ornamental or native plants in cultivation, like tree plantings, home landscapes, etc.), then it sounds like a certified arborist is the best choice if tree or shrub health assessments are needed. Your county Extension office can help share resources for both agricultural and horticultural needs, though most Agents in such offices are oriented towards agriculture more so than horticulture. (The Home and Garden Information Center is the hub of horticulture assistance for home gardeners across Maryland, though we're not located in a county Extension office.)

HGIC isn't able to offer on-site consulting, though Marylanders are welcome to submit questions on this Ask Extension platform about home and community gardening or horticulture topics, and we can help connect people with agriculture resources at UMD if needed. We generally refer questions about mature tree health to arborists, though, since making a diagnosis about tree health or causes of damage or decline can be difficult from photos.

While Extension doesn't collect information on arborists or maintain a database of area arborists or tree companies, we can point you to the organization that grants arborist certifications once they pass a standard exam, which has an online search tool for finding certified arborists. (See the linked page from the International Society of Arboriculture.) Some arborists are "consulting" arborists that work independently and aren't affiliated with or employed by tree-care companies. In Maryland, the other option is to hire a licensed tree expert, who should have essentially the same training and exam requirements that ISA-certified arborists have, even if they are not in the ISA's database.

Miri