What’s Wrong With My Rose?

By Gaye Hammond Master Rosarian – Houston Rose Society
Not too long ago I had the great good fortune to attend a lecture presented by Dr. Ed Bush, Associate Professor of Ornamental Horticulture at Louisiana State University titled “What’s Wrong with My Rose?”   According to Dr. Bush, most of the time a rose will send visible signals that something is wrong.  Rose gardeners know to look for disease symptoms like blackspot and powdery mildew and damage caused by insects, but plant changes caused by nutrient deficiencies can be subtle and may go unnoticed in the early stages.  The chart below provides a quick reference to helping diagnose nutrient imbalances in roses.

If your roses display symptoms from this chart, I would encourage you to send a soil sample to your State’s Soil, Water and Forage Laboratory for confirmation before taking remedial action to rectify any nutrient imbalance.  A soil test will not only identify nutrient deficiencies – it will also identify any nutrient levels that are too high as well as make recommendations for bringing the soil nutrient profile back into balance. Soil tests are inexpensive and the results are usually received within a week.  Forms and instructions for submitting a soil sample are available from your local Extension Service or contact your Master Gardener Association.

Figure 1 Yellowing between leaf veins can be caused by magnesium and manganese deficiencies.  Photo courtesy of Dr. Ed Bush, Louisiana State University

The highlighted cells in this chart represent the suspected deficient element (nutrient).  Abbreviations for the elements (nutrients) included in the chart are:

“N”
“P”
“K”
“Mg”
“Fe”

Nitrogen
Phosphorous
Potassium
Magnesium
Iron

“Cu”
“Zn”
“B”
“Mo”
“Mn”

Copper
Zinc
Boron
Molybdenum
Manganese

Symptom Suspected Deficient Element (Nutrient)Over Fertilization
 NPKMgFeCuZnBMoMn Over Fertilization
Yellowing of younger leaves     XX    XX 
Yellowing of middle leaves             XX  
Yellowing of older leaves XX  XX XX   XX    
Yellowing between veins    XX      XX 
Old leaves drop XX          
Leaf curls over    XX       
Leaf curls under   XX   XX     XXXXX
Leaf tips burn (younger leaves)        XX   
Leaf tips burn (older leaves)           
Young leaves wrinkle and curl   XX    XX XX XX  
Dead areas in the leaves   XX XX XX  XX   XX 
Leaf growth stunted XXXX          
Dark green / purplish leaves and stems  XX         
Pale green leaf color XX        XX  
Leaf spotting       XX    
Spindly plant XX          
Soft stems XX  XX        
Hard / brittle stems  XXXX         
Growing tips die   XX     XX   
Stunted root growth  XX         
Wilting      XX     

Chart courtesy of Dr. Ed Bush, Louisiana State University