New Texas Ranger Not Looking Good After Daily Watering

Q. I planted a Texas Ranger shrub three weeks ago in some sandy and rocky soil. I have been watering it with about two gallons daily. I added one inch-deep bark mulch in a 1 foot circle around the plant. Now I am finding yellow, brittle leaves on the lower stems and curling leaves on top. Am I overwatering?

A. Yes, it is definitely watered too often. Overwatering can be in two forms; giving too much water OR giving water too often or both at the same time. “Giving too much water” relates to the number of gallons you give a plant each time you water. “Watering too often” relates to how many times in a week you give water to a plant.

Texas ranger hedge sheared and consequently the flowers removed

            It is far more damaging if plants are watered too often rather than given too much in a single watering. Rangers do fine without wood mulch. They will benefit from it but they don't really need it like other plants, such as roses and many fruit trees in the rose family, do.

            Now, a second problem. If wood mulch is in contact with young tender stems of plants, it can contribute to a disease called collar rot. Collar rot basically rots the trunk of the plant in contact with continuously wet mulch just above the soil surface.

Collar rot of bean but the principles are the same.

            A third problem is just plain old root rot. This happens below ground and not at the soil surface. Root rot happens because the roots cannot "breathe" due to a lack of oxygen. The open spaces in the soil are continuously filled with water. Basically the roots "drown".

            Bottom line; pull the mulch away from the trunk about a foot or eliminate it. Make sure the plant is planted at the correct depth in the soil. Make a basin around the plant about 2 feet in diameter and fill this basin with water from a hose or bucket.

            Set your drip emitters for twice a week during the summer. On the same days your drip emitters come on, fill the basin with water. This helps settle the soil around the root system.

            When you see new growth, eliminate the watering in the basin. Use only the drip emitters from that point forward. Use enough emitters to deliver 1 to 2 gallons each time you water. Next year, add one more emitter but leave the number of minutes unchanged.

            Fertilize once in January. Do not use a hedge shears to prune unless you intend it to be a hedge. If the plant is intended to stand alone, use selective pruning and remove one or two of the largest stems near the base of the plant every two to three years.

A. Yes, it is definitely watered too much. Overwatering can be in two forms; given too much water OR giving water too often. It is far more damaging to plants to water them too often. Rangers do fine without wood mulch. They will benefit from it but don't really need it. If wood mulch is in contact with young tender trunks or stems of plants, it can contribute to a disease called collar rot. This disease is in the soil and can spread into healthy tissue if the plant is stressed.

The other concern is just plain old root rot. This happens because the roots cannot "breathe" due to a lack of oxygen to the roots. Basically the roots "drown". Plant parts without light need oxygen. Plant parts that are green and exposed to light need carbon dioxide AND oxygen. Keeping the soil moist and having the wood mulch in contact with the trunk is a double whammy on this plant. If the soil is amended at the time of planting (University of Arizona discourages that) then you should water only about twice a week right now. We are in nearly the same climate zone.

Bottom line....i hope it is not too late but pull the mulch away from the trunk about a foot or eliminate it. Make sure the plant is planted at the correct depth in the soil. Make a basin around the plant for the first few weeks and, in addition to your drip irrigation, water with a hose twice a week in the basin two feet in diameter surrounding the plant. This helps eliminate air pockets and settles the soil around plant roots. Actually you should be adding water to the planting hole when you are backfilling the hole with amended soil so the soil and water (mud) can flow around the plant roots. When you do this you will see air bubbles coming from the soil as the excess air is eliminated from the planting hole and around the roots.

When finished planting, the plant should be solidly established in the hole.

When you move the plant, it should not wiggle around in the soil. When you see new growth in a couple of weeks, eliminate the watering from the hose and go to emitters. Use enough emitters to give you 1-2  gallons each time you water. Next year, add another emitter. Fertilize once in January. Do not use a hedge shears to prune it but let it grow with little pruning.