Possible Clues:

• Garden shrubs – or try elms for a change
• Fragrant shrubs
• Fragrant shrubs (Pink)
• Aromatic shrubs yielding an essential oil
• Aromatic shrubs of Europe
• Evergreens — if failing, try elms
• Allspice and clove, e.g.
• It's my right to get Leslie, in short, for the shrubs
• Sly term for the evergreen shrubs?