Achillea ageratum, also known as sweet yarrow, sweet-Nancy, English mace or sweet maudlin, is a flowering plant in the sunflower family, native to Europe (Portugal, Spain, France, England, Belgium, Germany, Italy, Croatia and Romania) and Morocco.
The best course of action is to keep plants dry and to water at the base while making sure they have proper air circulation. Ageratums have shallow roots, so they can quickly dry out and wilt. Provide consistent water at least weekly, or more as needed during warm spells. To prevent foliar diseases, water in the morning so plants can dry out, or irrigate around the base of the plants rather than overhead.
Ageratums are heavy feeders and benefit from regular fertilizing. Mix a granular slow-release fertilizer into the soil at the time of planting and reapply mid-season, or use a water-soluble fertilizer twice monthly according to package instructions. Yellow leaves may be a sign that plants aren’t receiving enough fertilizer. Mulch with organic material such as shredded leaves or compost to suppress weeds and conserve moisture. Keep mulch several inches away from the base of the plant to avoid crown or stem rot.
Provide good air circulation, with temperatures between 65 (18 °C) to 75 F (23 °C) and nighttime temperatures between 50 t(10°C) to 60 F (15 °C).
