Perhaps you should try some spelling variations:
"horticulturist" » "agriculturist", "horticulturae"
"horticulturists" » "agriculturists", "horticulturaes"
"horticulturalists" » "agriculturalists"
"horticultural" » "agricultural"
"horticulture" » "agriculture"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((("horticulturist" OR "horticulturists") OR ("horticulturalists" OR "horticulturists")) OR (("horticultural" OR "multicultural") OR "horticulture")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((\"horticulturist\" or \"horticulturists\") or (\"horticulturalists\" or \"horticulturists\")) or ((\"horticultural\" OR \"multicultural\") or \"horticulture\"))".
• Removing quotes may allow a broader search: ((( horticulturist or horticulturists ) or ( horticulturalists or horticulturists )) or (( horticultural OR multicultural ) or horticulture )).
• Adding a wildcard symbol may retrieve word variants: ((("horticulturist" or "horticulturists") or ("horticulturalists" or "horticulturists")) or (("horticultural" OR "multicultural") or "horticulture"))*.