Q. I noticed all my Nandinas, also called heavenly
bamboo, are turning bright yellow. Is this a fungal disease problem? I’m
worried that whatever this is will spread to all the other plants.
bamboo, are turning bright yellow. Is this a fungal disease problem? I’m
worried that whatever this is will spread to all the other plants.
A. No, it is not caused by a disease organism. This is
severe iron chlorosis and fairly common to heavenly bamboo growing in alkaline
and desert soils.
severe iron chlorosis and fairly common to heavenly bamboo growing in alkaline
and desert soils.
Leaf yellowing happens frequently
because of a lack in organic matter in the soil, increasing alkalinity or soil pH.
I see heavenly bamboo planted with rock mulch and this yellowing frequently
becomes a problem in a few years after planting in these situations.
because of a lack in organic matter in the soil, increasing alkalinity or soil pH.
I see heavenly bamboo planted with rock mulch and this yellowing frequently
becomes a problem in a few years after planting in these situations.
 |
| Heavenly bamboo and rock mulch and yellowing |
Start a program of soil
enrichment and add a good quality iron product to the soil now as new growth is
appearing. If there is rock mulch present, remember this type of mulch is
probably adding to the problem. Plants like Nandina do not like rock mulch but
grow healthier in a wood mulch environment.
enrichment and add a good quality iron product to the soil now as new growth is
appearing. If there is rock mulch present, remember this type of mulch is
probably adding to the problem. Plants like Nandina do not like rock mulch but
grow healthier in a wood mulch environment.
Personally, I prefer iron EDDHAchelate as the source of iron to apply to the soil. It is a dry powder and must
be watered into the soil accompanied by a good quality fertilizer.
Iron does not move from the soil
into leaves that are already yellow. Iron applied to the soil only affects new
growth and new leaves. The only way to improve the green color of existing
yellow foliage is to apply iron fertilizers as a foliar spray.
into leaves that are already yellow. Iron applied to the soil only affects new
growth and new leaves. The only way to improve the green color of existing
yellow foliage is to apply iron fertilizers as a foliar spray.
Use any of the iron foliar
fertilizers (liquids or powders that are mixed with water to make a liquid) and
sprayed on the leaves. Sometimes it can take three or four applications, a week
apart, to get them to green up adequately. Some plants green up with a single
application.
fertilizers (liquids or powders that are mixed with water to make a liquid) and
sprayed on the leaves. Sometimes it can take three or four applications, a week
apart, to get them to green up adequately. Some plants green up with a single
application.
The water used when spraying liquid
iron should be distilled water. If using tap water, adjust the pH of the water
to 7.0. When making applications to leaves always use a wetting agent such as
EZ Wet.
iron should be distilled water. If using tap water, adjust the pH of the water
to 7.0. When making applications to leaves always use a wetting agent such as
EZ Wet.
You can also improve the new
foliage to dark green by pruning them back, close to the ground, and letting
them regrow after you apply iron EDDHA, compost, water and a fertilizer.
foliage to dark green by pruning them back, close to the ground, and letting
them regrow after you apply iron EDDHA, compost, water and a fertilizer.