Marin Rose Society

FAST FACTS - CHLOROSIS
by Nanette Londeree, Master Rosarian

SYMPTOMS

Paling (lighter green to lime-green color) or yellowing of interveinal (between veins) tissue

Leaves that are pale green, yellow, or yellow-white

Portions of the plant stunted or fail to produce flowers

Discolored leaves more prone to scorching and leaf diseases

CAUSE

Chlorosis, yellowing of green plant foliage due to a lack of chlorophyll development

Affected plant has little or no ability to manufacture carbohydrates due to chlorophyll insufficiency

OPTIMAL CONDITIONS

Low levels of iron in the soil

Soils with pH above 6.5 bind up the iron and make it unavailable to the plant roots

High concentrations of limestone (calcium carbonate) make the soil more alkaline (higher pH)

Roots that are damaged by a lack of oxygen in overwatered or poorly drained soils

Extreme soil temperatures and conditions that restrict air movement into soil like plastic sheet mulching, compaction

Soils that contain high levels of zinc, manganese, phosphorus or copper

TREATMENT

Prevention:

Maintain soil pH at 6.5 or lower through use of soil amendments

Maintain good drainage

Don’t overwater

Elimination:

Lower soil pH by incorporating acidic amendments such as peat moss or leaf mold

Add chelated iron to soil

Correct watering method / frequency

Correct drainage problem or move plant to pot or raised beds

GOOD GUY / BAD GUY?

This is a bad guy; the more chlorotic the plant the more severe the condition

If not corrected it can cause death of the plant

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