Question
QUESTION: I recently received a gift of a lovely gardenia plant in a small ceramic pot.  It was sent from a mail order flower company and appears to be well planted.  I live in Florida with an east/west exposure and would like to know what type of light and watering will yield best results and help it thrive.  Thanks for your help.

ANSWER: Sharyn,

In Florida a gardenia should be outdoors where it gets sun in the morning and shade in the afternoon. It likes bright light with morning sun, high humidity, acid fertilizer, night time temperature drops that it would get outdoors and they prefer acidic soil. The following websites have more info:
http://www.garden.org/plantguide/?q=show&id=2135

http://www.plantideas.com/in/in22.html

http://www.valentine.gr/gardenia_en.htm

If you have more questions write again. Good luck.

Darlene

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QUESTION: Much as I would like to plant it outside, I live in a condo and cannot do so.  I have a balcony but because of the extreme heat in Florida, I didn't think it was a good idea to put it there where it may get too much sun and dry out too easily.  I have it in front of a window where it gets afternoon sun and light throughout the day and I monitor the water carefully.  I'd appreciate any suggestions you might offer.

Answer
Sharyn,

If you want a Gardenia to survive in your home, you will have to create an environment just like the one where it grows naturally (southern China and Japan) with warm days, cool nights and moist, humid conditions.

The plant must have a rich, acid soil (pH of 4.5 - 5.5). A newly purchased plant will or should have this type of soil. The soil should be porous which allows water to drain through quickly and yet has the ability to retain moisture. Prepackaged acid based potting mixes that are prepared especially for gardenias, camellias and azaleas can be purchased at many garden centers. Repot the plant in a plastic pot or tub with good drainage holes. This is the best choice for this plant as we want to keep the gardenia's soil constantly moist. Repot the plant every 2-3 years, unless crowded roots demand earlier repotting of the plant.

The soil must always be 'slightly damp'. Its surface should always feel moist when it is touched. This calls for frequent watering and that's why the soil has to have good porosity (drainage) so it never becomes waterlogged. Water the plant with soft, tepid water from the top of the pot. Do not let the plant stand in water. Always empty the drain tray an hour after watering the plant! If the gardenia is over-watered, both leaves and flower buds will drop, and the roots will rot. Under-watering (allowing the soil to dry out) can also lead to leaf drop, but this is a slower process and the leaves may fall a week or two after the plant has been re-watered.

Sometimes, depending on the water supply, tap water can eventually change the pH of a soil. In other words, the soil will become alkaline instead of acidic. A plant disorder known as chlorosis can then affect the gardenia. The leaves will become pale colored (almost yellow) and have dark green veins. If this happens, the problem can be corrected by adding iron sulfate or iron chelate to the potting soil. Most garden centers sell these products. The usual mix is 1/2 ounce of either kind added to one gallon of tepid water. Water the plant with this mixture once or twice a week for a month or until the plant is back to normal health.

Daytime temperatures for the gardenia should be between 70-72 degrees F. Night temperatures are much more critical if you want the plant to bloom. If temperatures are allowed to rise higher than 60 - 62 degrees F. for even a few nights in a row, the plant will not set any new flower buds. To further complicate matters, a gardenia must not have any sudden changes in temperature, or be exposed to warm or cold drafts. Any sudden environmental changes can cause the buds to drop.

Fertilize the plant once a month while the plant is actively growing with a water soluble acid fertilizer formulated for acid loving plants (like gardenias). These formulas are less likely to change the soils pH. Follow directions on the labels for proper amounts. Another option is to use liquid fish emulsion fertilizer and apply it every two weeks. If the plant develops pale green colored leaves, a shortage of nitrogen fertilizer is probably the cause. Do not confuse this with chlorosis previously mentioned where the leaves are pale colored with dark green veins.

Many insect pests attack gardenias and can be troublesome unless proper control methods are used. The most injurious insects include scales, aphids, spider mites, thrips and whiteflies. Scale insects include cottony cushion, soft brown scale and others. These insects attach themselves to host plants after hatching and give stems or leaves a lumpy appearance. Scale insects are difficult to control especially as they mature. Spider mites can cause considerable damage especially during hot, dry periods. These small pests feed primarily on the underside of the foliage, causing colorless or whitish spots. Therefore, considerable injury usually has occurred when the homeowner notices the damage. Insects damage unopened buds, causing them to drop. Thrips and aphids are most troublesome. Usually pear-shaped aphids are visible but tiny thrips can go undetected until they cause considerable damage.

The cooler temps at night are going to be the most difficult to reproduce. Good luck.

Darlene