Q. I have a gardenia that is approximately four years
old. It blooms yearly and was doing great. All of a sudden,
literally overnight, the leaves turned yellow and are falling off. What
has happened? I water it daily, it is on the patio, outside where it has always
been, in the shade.
A. I think your gardenia developed rot. The symptoms of root
rot our yellowing leaves and leaf drop. Frequently the plant dies a relatively
slow death unless it’s in the heat, then it could be rapid.
old. It blooms yearly and was doing great. All of a sudden,
literally overnight, the leaves turned yellow and are falling off. What
has happened? I water it daily, it is on the patio, outside where it has always
been, in the shade.
A. I think your gardenia developed rot. The symptoms of root
rot our yellowing leaves and leaf drop. Frequently the plant dies a relatively
slow death unless it’s in the heat, then it could be rapid.
Container
plants need to be repotted regularly. When we grow in containers, the soil
organic matter (this is the component of the soil that helps keeps soil loose
and gives good air exchange to the roots) begins disappearing at a steady rate.
In a couple of years it will be in critical short supply.
plants need to be repotted regularly. When we grow in containers, the soil
organic matter (this is the component of the soil that helps keeps soil loose
and gives good air exchange to the roots) begins disappearing at a steady rate.
In a couple of years it will be in critical short supply.
As this
soil organic matter disappears, the open spaces in the soils that help with
drainage and air exchange, diminishes. At the very beginning, a good container
soil may contain as much as 50% of its volume as pore space.
soil organic matter disappears, the open spaces in the soils that help with
drainage and air exchange, diminishes. At the very beginning, a good container
soil may contain as much as 50% of its volume as pore space.
In about
three years this pore space may drop to only 20 or 15%. Basically the soil
collapses, losing its pore space. This might be okay for a palm growing in a
container but gardenias need soils with lots of pore spaces.
three years this pore space may drop to only 20 or 15%. Basically the soil
collapses, losing its pore space. This might be okay for a palm growing in a
container but gardenias need soils with lots of pore spaces.
The soil
becomes more dense, water drains through it more slowly, the soil stays wet
longer, salts begin to accumulate and the roots begin to suffocate.
becomes more dense, water drains through it more slowly, the soil stays wet
longer, salts begin to accumulate and the roots begin to suffocate.
Soil
diseases attack the weakened roots, roots begin to die, leaves begin to yellow
and drop from plant.
diseases attack the weakened roots, roots begin to die, leaves begin to yellow
and drop from plant.
Soils in
containers need to be renewed every two to three years depending on the type of
plant. Since gardenia is very susceptible to rots and grows much better in
aerated soils, I would repot it no longer than every other year.
containers need to be renewed every two to three years depending on the type of
plant. Since gardenia is very susceptible to rots and grows much better in
aerated soils, I would repot it no longer than every other year.
If the
Gardenia is not too far along in leaf yellowing and leaf drop, you might be
able to save it. Go to your favorite nursery or garden center and purchase a
good quality container soil, enough to refill the container. When you are
there, purchase a chemical fungicide called Subdue. Subdue fungicide does a
good job in controlling several of the root rot disease organisms. Applying a
fungicide alone will not solve the problem so you must repot the plant as well.
The plant can be put back in the same container if it is sanitized on the
inside or use a different clean container.
Gardenia is not too far along in leaf yellowing and leaf drop, you might be
able to save it. Go to your favorite nursery or garden center and purchase a
good quality container soil, enough to refill the container. When you are
there, purchase a chemical fungicide called Subdue. Subdue fungicide does a
good job in controlling several of the root rot disease organisms. Applying a
fungicide alone will not solve the problem so you must repot the plant as well.
The plant can be put back in the same container if it is sanitized on the
inside or use a different clean container.
Remove the
plant from the container during the cool temperatures of the morning and out of
direct sunlight. Once the plant has been removed from the container, you must
repot it quickly because the tiny feeder roots are continually dying after
removal from the soil and drying out. Place the plant on a clean surface and gently
wash the soil away from the plant roots.
plant from the container during the cool temperatures of the morning and out of
direct sunlight. Once the plant has been removed from the container, you must
repot it quickly because the tiny feeder roots are continually dying after
removal from the soil and drying out. Place the plant on a clean surface and gently
wash the soil away from the plant roots.
Thoroughly
clean the container and sanitize the inside of it with a 200 ppm solution of
bleach and water. This would be about on tablespoon of bleach in one gallon of
water. Rinse the container and wipe out the excess with a clean rag or towel.
Let it air dry in the sun for a few minutes to let the chlorine dissipate. Or
use a clean, fresh container.
clean the container and sanitize the inside of it with a 200 ppm solution of
bleach and water. This would be about on tablespoon of bleach in one gallon of
water. Rinse the container and wipe out the excess with a clean rag or towel.
Let it air dry in the sun for a few minutes to let the chlorine dissipate. Or
use a clean, fresh container.
Once you
have removed as much soil from the roots as possible with water, you can repot
the plant and use tap water to resettle the soil around the roots and remove
air pockets. You will apply the subdue fungicide according to the label and
water it into the soil of the repotted plant as a soil drench. Follow label
directions.
have removed as much soil from the roots as possible with water, you can repot
the plant and use tap water to resettle the soil around the roots and remove
air pockets. You will apply the subdue fungicide according to the label and
water it into the soil of the repotted plant as a soil drench. Follow label
directions.
Fertilize the plant as you would normally and watch for new
growth to come from leafless stems that are still alive. Once a year or once
every two years remove about one third of the soil from the container and add
new container soil.
growth to come from leafless stems that are still alive. Once a year or once
every two years remove about one third of the soil from the container and add
new container soil.
Do gardenias in the ground need any treatment to maintain their pore space?
Also, for a potted gardenia I would not use a saucer to retain water.
Applications of organic matter to the soil surface or organic mulches that decompose such as wood chips would be enough if they were planted with organic amendments at the time of planting in our very low organic matter soils. Soils with higher OM at the start would need less, if any, at the time of planting but would still benefit from organic mulches.