Q.
I have a
gardenia that is approximately four years old. It has bloomed yearly and was
doing great until all of a sudden, literally, about 75% of the leaves turned
yellow and fell off. It is on the patio, outside, where his always been in the
shade and I water daily.
I have a
gardenia that is approximately four years old. It has bloomed yearly and was
doing great until all of a sudden, literally, about 75% of the leaves turned
yellow and fell off. It is on the patio, outside, where his always been in the
shade and I water daily.
.jpg) |
| Gardenia with leaves yellowing. |
A. I
think your gardenia has developed root rot. This is fairly common in guarding. The
symptoms of root rot is yellowing leaves and leaf drop. Frequently the plant
dies a relatively slow death unless it’s in the heat, then it could be rapid.
You
didn’t come out and say it but it sounds like the plant is in a container. When
we grow in containers, the soil organic matter part of it (this is the part
that helps keeps the soil loose and gives good air exchange to the roots)
begins disappearing at a steady rate. It will be in a critically short supply
by the third year. As soil organic matter disappears over time, the open spaces
that help with drainage and air exchange, diminishes.
didn’t come out and say it but it sounds like the plant is in a container. When
we grow in containers, the soil organic matter part of it (this is the part
that helps keeps the soil loose and gives good air exchange to the roots)
begins disappearing at a steady rate. It will be in a critically short supply
by the third year. As soil organic matter disappears over time, the open spaces
that help with drainage and air exchange, diminishes.
.jpg) |
| Gardenia with dark green leaves, a sign of health. |
At
the very beginning, a container soil may contain as much as 50% of its volume
in pore space. Over three years this pore space could drop to only 20 or 15%.
Basically the soil collapses, losing its pore space.
the very beginning, a container soil may contain as much as 50% of its volume
in pore space. Over three years this pore space could drop to only 20 or 15%.
Basically the soil collapses, losing its pore space.
Collapsing
soil becomes more dense, water drains through it more slowly, the soil stays
wet longer, salts may 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.
soil becomes more dense, water drains through it more slowly, the soil stays
wet longer, salts may 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.
This
is why 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 not go longer than every other year.
is why 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 not go 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.
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 containing Subdue. Subdue
fungicide does a good job in controlling several of the root rot disease
organisms.
you are there, purchase a chemical fungicide containing 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.
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,
repot it quickly because the tiny feeder roots die quickly when exposed to the
air. 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 disappear. Or you
can 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 disappear. Or you
can use a clean, fresh container.
Once
you have carefully removed as much soil from the roots as possible, 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.
you have carefully removed as much soil from the roots as possible, 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 every two years remove about one third of the
soil from the container and replenish the container soil.
the plant as you would normally and watch for new growth to come from leafless
stems that are still alive. Once every two years remove about one third of the
soil from the container and replenish the container soil.