Gardenia Bushes for Zone 6

Cold-Hardy Gardenia Hybrids

• “Chuck Hayes” (Gardenia jasminoides “Chuck Hayes”) and “Grif’s Select” (Gardenia jasminoides “Grif’s Select”) are hybrid gardenia cultivars that grow to a height of 4 to 6 feet. They are both evergreen and produce fragrant, white flowers from spring to fall. “Chuck Hayes” is hardy in USDA zones 6b to 11, and “Grif’s Select” is hardy in USDA zones 6a to 11.

Sun Exposure

• Both of these gardenia hybrids should be planted in partial shade with cool morning or early evening direct sun exposure and shade in the afternoon. The afternoon shade must be provided consistently all year. Shade from a deciduous tree will not be sufficient in the winter. The gardenias also require protection from strong winds. They can be planted between larger evergreen shrubs or trees with 4 to 6 feet of open space on either side of the gardenia. A foundation planting on the east side of a house provides protection and morning sunlight with shade in the afternoon.

Soil Requirements

• Gardenias require organically rich, acidic soil that drains quickly. Test the soil pH six to 12 months before planting the gardenias. “Chuck Hayes” requires soil with a pH of 5.6 to 6.5. “Grif’s Select” requires soil with a pH of 5.6 to 6.0. Treat the soil with 1/2- to 5 pounds of lime per 25 square feet to raise the pH if it is below 5.6. Treat the soil with 1/4- to 3/4-pound of sulfur to lower the pH if it is above 6.0 or 6.5. The amount of lime or sulfur necessary to change the pH will depend on the soil. Sandy and loamy soil requires less lime or sulfur to change the pH than clay soil. Mix the sulfur or lime into the soil as soon as the soil test is finished, since it can take six months to one year for the pH to change. Soil with a pH above or below the gardenia’s range will result in chlorosis, due to the shrub’s inability to absorb nutrients. Mix a 3- to 6-inch layer of aged cow manure, compost, ground tree bark, leaf mold or peat moss into the top 10 inches of soil before planting gardenias.

Gardenia Care

• Water gardenias once or twice each week. They like uniformly moist soil but often develop root rot in overly wet or slow-draining soil. Build a raised bed for them where the soil drains slowly. Sprinkle 2 tablespoons of granular10-10-10 fertilizer for acid-loving plants over the root zone at the end of March, and again at the end of June, beginning the year after planting. While 2 tablespoons is a common application rate, follow the fertilizer manufacturer’s recommendations. Hose the gardenia with a strong spray from a garden hose in the morning if it is attacked by aphids, mealybugs, scales, spider mites or whiteflies. Use a tooth brush or a cotton ball and rubbing alcohol to remove scales. Branches that are severely infested with scales or sooty mold should be pruned off.