A new and distinct cultivar of Ageratum plant named ‘Sage00591’, characterized by its tall, upright and mounded plant habit; freely branching habit; dense and bushy plant habit; dark green-colored leaves; freely flowering habit with numerous inflorescences per plant; and inflorescences rayless with light red purple-colored disc florets.

CROSS-REFERENCE TO RELATED APPLICATIONS

Ageratum Plant Named ‘Sage85015’; Diony de Bont, Applicant; disclosed in a U.S. Plant Patent application filed concurrently.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofAgeratumplant, botanically known asAgeratum houstonianumand hereinafter referred to by the cultivar name ‘Sage00591’.

The newAgeratumis a naturally-occurring whole plant mutation of theAgeratum houstonianumcultivar Red Top, not patented. The newAgeratumwas discovered and selected by the Inventor as a plant within a population of plants of the cultivar Red Top in a controlled environment in Ter Aar, The Netherlands in 2001. The selection of the newAgeratumwas based on its compact plant habit, strong plant growth, large inflorescences and attractive floret coloration.

Asexual reproduction of the newAgeratumby terminal cuttings in a controlled environment in Ter Aar, The Netherlands since October, 2002, has shown that the unique features of this newAgeratumare stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The following characteristics have been repeatedly observed and are determined to be basic characteristics of ‘Sage00591’ and distinguishing the newAgeratumas a new and distinct cultivar:1. Tall, upright and mounded plant habit.2. Freely branching habit; dense and bushy plants.3. Dark green-colored leaves.4. Freely flowering habit with numerous inflorescences per plant.5. Inflorescences rayless with light red purple-colored disc florets.

Plants of the newAgeratumdiffer from plants of the parent, the cultivar Red Top, in the following characteristics:1. Plants of the newAgeratumwere more uniform than plants of the cultivar Red Top.2. Plants of the newAgeratumhad larger inflorescences than plants of the cultivar Red Top.3. Plants of the newAgeratumand the cultivar Red Top differed in disc floret coloration.

Plants of the newAgeratumdiffer from plants of the cultivar Sage85015, disclosed in a U.S. Plant patent application Ser. No. 11/146,230, primarily in disc floret coloration.

Plants of the newAgeratumcan be compared to plants of the cultivar Hawaii Shell Pink, not patented. In side-by-side comparisons conducted in Encinitas, Calif., plants of the newAgeratumdiffered from plants of the cultivar Hawaii Shell Pink in the following characteristics:1. Plants of the newAgeratumwere taller and more vigorous than plants of the cultivar Hawaii Shell Pink.2. Plants of the newAgeratumwere stronger and had thicker lateral branches than plants of the cultivar Hawaii Shell Pink.3. Plants of the newAgeratumhad larger inflorescences than plants of the cultivar Hawaii Shell Pink.

DETAILED BOTANICAL DESCRIPTION