Nutrient-depleted soil source of plants’ ill health

: My Indian hawthornes were looking quite healthy but a small part of a bush will start dying as if the bush was not getting enough water. Very quickly, in a matter of a week or two, this spreads to the whole bush. The two northernmost bushes, which get more direct sun from the west, have already died. These hawthornes were part of the original landscaping when we bought the house new in 1996.

A: For the most part, we can probably eliminate disease or insect problems as Indian hawthornes are not particularly prone to either. What they are prone to is becoming sickly due to a depletion of soil organic matter and loss of nutrients over time. This is particularly true if they are in soils that are covered in rock or mulches that do not decompose. In particular, they are very subject to iron chlorosis and a general lack of health over time.

As these plants get more unhealthy due to a depletion of soil nutrients they will become more susceptible to heat and direct sunlight. In other words, as these plants get more and more unhealthy they are less and less tolerant of adverse conditions. As they become less and less healthy, they no longer have the tolerance for the same location and exposure as they did before

What to do? This is not a quick fix. Since it may have taken many years to get to this point it will not be fixed in a week. The key is to start putting nutrients back in the soil and get it on a regular program of nutrient replenishment.

You probably will not see much improvement the remainder of this year. But, you can try applying Miracle-Gro (or any high-quality foliar fertilizer) along with multiple applications of an iron chelate spray once a week for three to four weeks. Use one teaspoon of liquid detergent (like Ivory) per gallon of water when spraying these fertilizers on the foliage.

Accompany this with a soil application of a complete fertilizer near the source of the irrigation so that the water washes the fertilizer into the root zone. Apply an iron chelate to the soil, such as Organo’s KeRex. Apply that now as well as again in January or early February.

You should see a big improvement next spring in the new growth, which should be dark green with large leaves. This new foliage will cover the damaged foliage over time.

Remove any dead branches now. I also would start to apply compost to the soil surrounding the plant and water it in anytime now until next spring.

The other option you have is to remove these plants and start over. You did get 13 years out of them, which is a pretty good deal. It might be cheaper in the long run with faster results. Use plenty of compost in the planting hole and sidedress these plants with compost frequently. They like iron applications on an annual basis and annual fertilizer applications as well.

Q: I live here in Las Vegas and I have a pomegranate tree that is sadly overgrown. It still bears fruit and I really need to trim it back. I just removed all of the fruit and wondered if it is OK to prune it now?

A. It can be done at this time if you are in a pinch but it is best to wait until all the leaves have dropped so you can see the plant’s architecture and make better pruning choices. You would want to discourage any new growth immediately following pruning so late in the fall will work, but nothing beats being able to see your cuts and places to make these cuts.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.