White Ageratum
Dondo White Ageratum brings clean, crisp elegance to garden beds and borders with its pure white flower clusters held on upright stems. This cultivar of Ageratum houstonianum grows 24 to 30 inches tall in hardiness zones 10 and 11, thriving in full sun to partial shade with moderate water needs. Start seeds indoors 6 to 8 weeks before your last frost date at 70°F for best germination, then transplant outdoors once frost danger passes. The tall, columnar habit makes it stand out among ageratum varieties, offering vertical interest that shorter cultivars simply cannot match.
Partial Sun
Moderate
10-11
30in H x 12in W
Annual, Perennial
Moderate
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Dondo White produces abundant white flowers on a notably tall, upright form that reaches 24 to 30 inches, creating dramatic height in containers and borders where other ageratums fall short. The moderate water requirement and tolerance for both full sun and partial shade give you flexibility in placement, while its frost-tender nature makes it an annual in most climates, requiring fresh seed each year. Those seeking a tall ageratum with crisp white color will find this variety fills a specific niche that dwarf cultivars cannot.
Start seeds indoors 6 to 8 weeks before your average last frost date. Maintain a germination temperature of 70°F. Press seeds into the surface without covering, as light aids germination.
Transplant seedlings outdoors after your average last frost date when soil has warmed and frost danger has completely passed. Space plants 12 inches apart. Hardening off is recommended before transplanting to acclimate seedlings to outdoor conditions.
Direct sowing is not recommended except in very mild climates. If attempting direct sowing, wait 2 to 4 weeks after your average last frost date.
Deadheading spent flower clusters will encourage continued blooming throughout the season and maintain the upright form.
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