Plant of the Month – July 2020

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PLANT OF THE MONTH

gardenia

Gardenia jasminoides

Nothing says summer in the south like the fragrant blooms of Gardenia. One sniff and fond memories of carefree summer days as a youth remind us of days gone by. Gardenias are subtropical plants that thrive in warm, humid weather. Most gardenias are hardy in zones 8-11, though a few varieties are hardy to zone 7 (Klein’s Hardy gardenia), and a few are only hardy in zones 10 and 11 (including Double Tahitian gardenia).

Gardenia is a perennial evergreen shrub with 200 species that prefers acidic soil at 5-5.5. If soil is too alkaline, leaves will yellow and blooms may drop. To combat this, apply a sulfur-based fertilizer. Blooms are white to pale yellow, single or double, with strong fragrance. Gardenias prefer full sun to partial shade and grow best when they are deeply watered at regular intervals. Soil should be well-drained, acidic, and organically rich. Most are resistant to damage by deer. Some species have various fungus and insect problems.

Gardenia jasminoides “Kleim’s Hardy’ is a semi-dwarf, cold-hardy gardenia with showy, highly fragrant white flowers, shown off by bright golden stamens and thick lustrous dark emerald green foliage. It can be a houseplant or planted outdoors. In hot climates it prefers morning sun with afternoon shade. Be sure to use organic mulch to cover the roots. This variety may suffer from many insects and diseases.

Gardenia jasminoides ‘Radicans’ is a creeping, dwarf variety. Heat and drought-tolerant, this gardenia is low and spreading and can be planted to form a beautiful low-hedge groundcover. It can also be grown in large containers and allowed to spill over the edges. Plant in a protected area to avoid strong afternoon sun and strong cold winds in the winter. It is an excellent “filler” for east and southeast exposures with morning sun. This variety is an excellent foundation plant that is 1-2 feet tall, compact (2-3 feet wide), evergreen, with a sweet-smelling white flower in the summer. It will put on a big flush of blooms in late spring, and then it will bloom off and on through the summer.

Radicans gardenias                         ‘Radicans’                                            

Gardenia jasminoides ‘Crown Jewel’  is a dwarf gardenia that is compact, cold hardy,  and gorgeous. It is a hybrid of ‘Kleim’s Hardy’ for dwarf size and prolific flowering, and the cold hardiness and double bloom of ‘Chuck Hayes.’  ‘Crown Jewel’ has attractive, dark green, evergreen foliage on a plant that will grow only 2-3 feet in height and 5 feet in width. It has a mounding plant habit with white, intensely sweet, fragrant flowers in summer. Blooms appear on both old and new wood. Use ‘Crown Jewel’ as a low hedge, foundation plant, or in a group planting in a sunny, well-drained area.

‘Summer Snow’ is a cold-hardy hybrid for zones 6-10. This shrub grows to 4-5 feet in height with an equal spread. It has pure, crisp white double flowers that resemble roses. It is drought tolerant and mostly pest resistant. This variety is a very classic, elegant type of gardenia.

Summer snow gardenia

’Summer Snow’

‘Shooting Star’ is a particularly fragrant gardenia with a winter hardiness of zones 7-10. It does best in acidic, well-drained soils in full to partial sun; sheltered from high winds. ‘Shooting Star’ grows 3-4 feet tall and produces large, 3 inch single flowers in a stark white color from May to June. 

For answers to your horticulture questions, contact the N.C. Cooperative Extension, Currituck County Center at 252-232-2261.

By Peggy Lilienthal,  Master Gardener℠ Volunteer in Currituck County

Reference:

Extension Gardener Plant Toolbox

Gardenias