Why Does The Foliage Of

Is your gardenia planted or placed somewhere where it can get lots of morning sunlight but is protected from scorch by afternoon shade?

Has the temperature dropped below 60 °F recently?

Is the soil where your gardenia is planted rich in nutrients and organic matter?

Is the soil slightly acidic?

Do the roots have small galls?

Was your gardenia sitting in the soggy soil for some time?

Gardenias love full sun, but afternoon shade is appreciated during warmer months of the year. Hot afternoon rays can scorch the leaves and give them unsightly, dry look, but too little sunlight and the plant won't have enough energy for healthy growth. In colder areas, gardenias will tolerate full sun.

Gardenias grow best when the day temperatures are in the range of 65-70 °F, and the night temperatures do not go bellow 60 °F. Lower temperatures may cause leaf yellowing and drop.

Gardenias are heavy feeders so they prefer rich soils. Poor soils will cause leaves to turn yellow and drop. Adding peat moss or manure to the soil will provide nutrients and enhance the growth of your gardenia.

Gardenias need lots of available iron in the soil to produce chlorophyll. They prefer slightly acidic soils with a pH between 5.0 and 6.0. If the soil is alkaline the iron won't be available to plants and they could suffer from iron chlorosis.

Various nematodes can feed within gardenias roots causing sickly look and yellowing leaves. You can only prevent nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes.

If your gardenia was sitting in the soggy soil, it may have suffered from root rot. If your plant is small enough to dig, check the roots. They should be firm and white or cream-colored, but not black or squishy. Cut all rotted roots and if the rotting is serious you may need to discard the plant.

Over-watering or under-watering is often a cause for yellow foliage in gardenias. These plants need about an inch of rain each week. The soil needs to be constantly moist but never soggy or flooded. Keep your gardenia in well-drained soil and do not let it dry up completely or let the plant sit in soggy soil.