Causes for Yellowing of Mock Orange

Q. Can you tell what is happening to my mock orange shrub?  They are 3 to 4 years old and getting enough water. They were planted in topsoil used in other locations with good results. They are the fourth different plant I tried to grow in this area without good results. The leaves are turning brown starting at the tips.

Readers mock orange

A. From your picture the leaves scorching like that could be not enough water applied or not applied frequently enough or even too frequently; high intensity sunlight and intense heat from surfaces radiating heat back to the plant; using a poor soil amendment at planting; lack of fertilizer or a lack of an iron fertilizer because the leaves are yellowing.

Mock orange, not dwarf, in good condition

These problems can be working alone or in combination with each other. If just one of these problems is present, it can affect the overall ability of the plant to combat extreme desert conditions such as high temperatures, low humidity and poor soils.

Mockorange is not a desert plant to begin with so we have to put more resources into keeping it look good. It’s one of those plants that does well if it is in the right location with the right type of soil amendments and irrigation.

Address the potential water issue first. I would flood the areas with a hose once a week in addition to your normal waterings. Make sure you are not watering daily but every 2 or 3 days right now.

Add good quality compost to the area. This can be on top of any mulch you have and water it in. Fertilize with a good quality fertilizer such as Peters, Miracle Gro or Osmocote. Add soil iron in the form of iron chelate, use only EDDHA iron chelate if applying it to the soil.

Water thoroughly giving the plant roots a chance to breathe and the soil to drain between flooding. Look for improvement to the plant the following spring (February to May). It is too late in the season now to see much improvement in growth.