by Pauline Muth

This article was taken from THE TWIG - The newsletter of the Mohawk Hudson Bonsai Society and is used with permission - ED.

The dwarf gardenia is an evergreen shrub in zones 7b to 9. It has a moderate to rapid growth rate growing to up to two feet in height and spread up to 3 feet. It grows in sun, but will take partial light shade and needs acidic soil. Although it is heat and somewhat drought tolerant, it is best kept evenly moist in bonsai culture. It can be damaged by cold winds. The leaves are glossy and dark green that turn bright yellow as they are shed. The plant has creamy white flowers in May and June and into summer, depending on your zone.

Climate

For bonsai purposes, it is considered to be subtropical and will survive down to a 40 degree F temperature. The idea climate will have hot summers with cool nights. In cooler climates, it is brought out for frost-free weather and returned to the greenhouse or light garden culture in the fall after leaf loss. In temperatures near 70 degrees F, growth will be tight with short inter-nodal spaces. Give this species as much light as possible. If brought into the greenhouse, keep damp and the bonsai will bud out in late winter.

Soil

Gardenia needs acid soils. The soil must have excellent drainage. The plant must receive plenty of water during the growing period, but it just kept damp in the cool of winter. Constant wet soil is harmful to the species. Using a mixture of a good potting soil and a bonsai medium works well for this species. If you are in an area with heavy rainfall or if you are a heavy waterer, use only bonsai medium. It needs high phosphorus fertilizer for bloom and applications of iron twice during the growing season to prevent chlorosis. Begin fertilizing when buds swell and stop during the flowering period. Continue fertilization after flowering is complete.

Repotting

Repotting is best done in late winter or early spring before the buds leaf out. In fast growing young plants, yearly repotting with root pruning is needed. In established plants, repotting should be done every two years.

Sun Exposure

Although full sun is preferred, take care not to burn the leaves during hot dry periods. It will tolerate some shade. If the plant has leaved out indoors or in a greenhouse, expect sun burn on the developed leaves when you put it outdoors. The leaves that sprouted indoors will have too thin a cuticle layer for exposure to the sun. The leaves that sun burn will eventually fall off as new leaves sprout and develop the proper cuticle layer of protection.

INDOORS: grow lights that are very close to the bonsai, unless they are halide or halogen, are necessary for continued growth. In a cool greenhouse, they lose much of their leaves in winter and sprout out in January or February.

Flowers

The flowers are beautiful and tender with a wonderful fragrance. Enjoy quickly as they soon fade and brown.

Training and Pruning

The tree is best worked in late winter or early spring for hard pruning. Wire only the trunk and woody branches, and raffia protection before wiring in young plants is suggested. It can be wired at any time. Larger branches can be very brittle. The use of raffia on woody branches is suggested to help prevent cracking after wiring and bending. Trimming of new shoots (those with 4-6 pairs of leaves) to one or two pairs of leaves throughout spring and summer is needed. Propagation

It can be propagated by mid summer soft wood cuttings, leaf-less hardwood cuttings in winter, air layering or seeds. Bottom heat and rooting hormone is required for cuttings.

Problems

Treating the plant to a soap spray and wash periodically will reduce insect problems, and good air circulation will prevent mildew attacks. To prevent disease and insect problems it needs excellent air circulation.