• Gardenia topiary

    Gardenias are a favorite flower most memorable for their mesmerizing fragrance. Although they are typically grown in areas where the winters are warm, gardenias are also quite capable of living in a pot and being transported indoors during the cold season, as long as their finicky needs are met.

    Basically, gardenias prefer warm, humid environments, bright indirect light, and acidic soil.

    Gardenias should be fertilized once every three weeks with an acidic fertilizer.

    Typical Problems and Solutions


    Too Dry

    The dry, hot air typical of indoor heating will quickly cause the gardenia flowers to fall. High humidity is mandatory to keep your gardenias happy and healthy. You can increase humidity by using a humidifier or placing your potted gardenia in a tray with pebbles and water, however, avoid misting the leaves of your gardenia because this can lead to fungal growth. It is recommended to give your gardenia a good soak once a week. First you should poke your finger into the top inch of soil to assure that it is dry.


    Yellow Spots

    Yellow spots are caused by either cold temperatures, poor drainage, or low soil acidity levels. The gardenia prefers a temperature of between 65°-70°F during the day, and 60°-62°F at night. Remember to only water the base of the plant when the soil is dry 2 inches below the surface. Gardenias prefer their soil to maintain a pH level between 4.5 – 5.5. To increase acidity, add a soil acidifier.

    yellow leaf gardenia


    Fungal Growth

    As mentioned, misting your gardenia will likely lead to fungal growth. Also, avoid crowding your plants too close together, as a lack of air flow can also lead to fungal problems.

    If your gardenia develops a fungal issue, try to determine which fungus is affecting the plant. There are five main types of fungus that attack gardenias: powdery mildew, leaf spot, sooty mold, rhizoctonia leaf spot, and canker.

    What To Do

    Powdery mildew (white spots) and Leaf Spot: Remove infected leaf or stem. Spray with a folia fungicide (sulfur, neem oil, or horticultural spray) according to manufacturer’s direction. You may also try spraying the entire plant and soil with a solution of 1tsp baking soda to a quart of water.

    powdery mildew

    powdery mildew

    Sooty Mold (may appear as black spots): In less severe cases, the sooty mold can be wiped from the leaves. In more severe cases, wash the infected areas with soap and water, prune away any wilted or dead foliage, and spray the plant with insecticidal soap. Sooty mold grows on the exudate of white flies, so if your plant has sooty mold, the white flies must be eliminated.

    sooty mold

    sooty mold

    Rhizoctonia Leaf Spot (appears as brown spots): Remove and destroy all affected parts of the plant. It is also suggested to transplant your gardenia into sterilized soil and a sterilized pot, and sterilize your hands after handling infected foliage before touching the healthy plant. Avoid wetting the foliage and overwatering the plant. Assure the plant has proper drainage, and prune to improve air circulation.

    rhizoctonia leaf spot

    rhizoctonia leaf spot

    Canker: This is the most serious disease for the gardenia. This occurs when a bacteria or fungus enters a wound in the gardenia. It appears as a swollen stem at or below the soil line. The area above the canker will be bright yellow and the bark may become corky and cracked. You will need to destroy the entire plant. Clean tools used to cut the infected plant, and do not replant another gardenia in the soil of the infected plant.

    canker

    canker


    Pests

    Insects that can damage your gardenia are aphids, mealy bugs, spider mites, thrips, scale, and white flies (already mentioned).

    Signs Of Damaging Insects

    Aphids: They feed on gardenia plant and reproduce quickly. They cause leaves to appear curled/distorted, stunt the growth of the plant, and reduce flower production. Like white flies, their excretions can cause sooty mold.

    aphids

    aphids

    Mealy bugs: These are grey, segmented, sap-sucking pests that feed in clusters, and shed a white waxy or cotton like coating over the areas they are infesting. In minor cases they can stunt growth, and inmore severe cases can cause premature leaf drop and twig dieback.

    mealy bugs

    mealy bugs

    Spider mites: These can be difficult to discover until there is a full blown infestation. They feed on the underside of leaves causing yellow or white speckles on the leaves. Often affected foliage looks deformed and these tiny spider leave a fine webbing on the underside of leaves, but can cover the entire plant in severe instances.

    spider mites

    spider mites

    Thrips: Many people say these insects look like worms with wings, and like the other pests mentioned, their presence can make leaves appear disfigured and discolored.

    thrip

    thrip

    Scale: There are several species of these. These insects have small, flat bodies, and no visible legs or antennae. These pests can be easily mistaken for plant tissue or fungal infections, and populations can reproduce quickly.

    scale

    scale

    White fly: Small populations of these insects typically do not do much damage, but it is best to be rid of them before they become a problem.

    white flies

    white flies

    What To Do

    Since gardenia pests are difficult to control with insecticides, it is best to maintain optimal health of your plant by maintaining proper temperature and moisture controls to deter the pests previously mentioned. If your plant becomes infected there are some general steps to take:

    1. Prune and destroy infested foliage.
    2. Brush off leaves and vacuum whiteflies from the air.
    3. Touch any visible bugs with a cotton swab dipped in alcohol. (Avoid getting alcohol on leaves.)
    4. Use insecticidal soap or horticultural oil on large infestations. See this website for more specific precautions 5. Avoid broad-spectrum insecticides because these also kill beneficial insects.

    Persnickety though they may be, the extra effort of caring for your indoor gardenia is worth the unforgettable fragrance, and beautiful blossoms displayed on this tropical favorite. If you still encounter problems with your gardenia, or you need a soil ph test, insecticidal soap, or fertilizer for your gardenia, come in to St. Matthews Feed & Seed and we would be glad to help you find solutions to keep your gardenia healthy and blooming.

    Links That Could Be Helpful:

    Controlling mealy bugs

    Gardenia Plant Care

    Controlling Thrips