Gardenia plant named ‘ST-15-20’

A new and distinct cultivar of Gardenia jasminoides plant named ‘ST-15-20’, characterized by fragrant, double white flowers, abundant large flowers in spring with reblooming to fall, lustrous, dark green foliage, compact growth habit, cold hardy to USDA Hardiness Zone 7.

Genus and species of plant claimed:Gardenia jasminoides

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofGardenia jasminoides, a member of the Rubiaceae family, hereinafter referred to by its cultivar name ‘ST-15-20’. This cultivar is grown primarily as an ornamental for landscape use and for use as a potted plant.

The newGardeniacultivar originated from an open pollination ofGardenia jasminoides‘PIIGA-II’, (U.S. Plant Pat. No. 27,258), in Watkinsville, GA, in 2020 and was selected from the progeny by continued evaluation for growth habit, foliage, and floral characteristics.

‘ST-15-20’ has been asexually reproduced by softwood cuttings in Watkinsville, GA, since 2020, and the characteristics of the cultivar have been stable and reproduced true-to-type in successive vegetative generations.

SUMMARY OF THE INVENTION

‘ST-15-20’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with changes in light, temperature, soil, and rainfall without, however, any variance in genotype.

The following traits have been observed and represent the characteristics of the new cultivar. In combination these characteristics distinguish ‘ST-15-20’ from all other varieties in commerce known to the inventor. 1) Fragrant, large, double white flowers. 2) Abundant flowers in spring with reblooming to fall. 3) Lustrous, dark green foliage. 4) Compact growth habit. 5) Cold hardy to USDA Hardiness Zone 7. There are no other cultivars ofGardeniawith this combination of characteristics known to the inventors.

PARENTAL COMPARISON

‘ST-15-20’ is distinguished from its female parent,Gardenia jasminoides‘PIIGA-II’ (U.S. Plant Pat. No. 27,258), by its size. ‘ST-15-20’ is more compact with shorter internode length, smaller lustrous dark green foliage, and a smaller overall plant than ‘PIIGA-II’.

COMMERCIAL COMPARISONS

‘ST-15-20’ can be distinguished from ‘ST-07-20’ (U.S. Plant Pat. No. 34,958) by its habit. ‘ST-15-20’ has a compact growth habit, whereas ‘ST-07-20’ has a columnar growth habit.

‘ST-15-20’ can be compared to ‘Chuck Hayes’ (US Plant Pat. No. 8,755). ‘ST-15-20’ is more compact with shorter internodes than ‘Chuck Hayes’. ‘ST-15-20’ is a more prolific rebloomer than ‘Chuck Hayes’. ‘ST-15-20’ is more cold hardy than ‘Chuck Hayes’.

DETAILED DESCRIPTION

In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used. Plants used for the description were approximately 3 years old and were grown in 11.36 L containers in full sun under outdoor conditions in Watkinsville, GA.