Oleanders Struggling in Desert Soil

Q. We planted new oleanders a month ago and fertilized them with Epsom salts and gypsum. They have yellow leaves that are dropping already. What can we do to stop the yellowing of the leaves?

A. Oleander should be one of the easiest plants to grow in this climate and soils. Something is definitely wrong. Gypsum and Epsom salts are not complete fertilizers. They contain a lot of calcium and sulfur as well as some magnesium but nothing to encourage plant growth.

            Select a fertilizer that contains nitrogen, phosphorus and potassium such as 16–16–16 or some type of fertilizer for trees and shrubs.

You didn’t mention mixing compost with the soil when it was planted. I hope the soil was amended with organic matter like compost at the time of planting. This is extremely important for plants growing in our desert soils.

It is important to add compost with the soil at planting time

Make sure the planting hole is filling with water at planting time. This practice is not as important in soils found in wetter climates but can be an extremely important practice for our soils.

Add enough water at each irrigation to thoroughly wet the soil surrounding the plant roots to a depth deeper than the container. Build a donut or moat around the plant that can be filled with water. Irrigate with a hose, filling this moat, the first three weeks after planting.

Add water to the planting hole at the same time you are backfilling it with soil