Mulberry leaves tips burning, new leaves deformed

Question

This has started to happen about 2-3 weeks ago, and is not stopping.

One reason that I think caused all this is heat. The temperature here was was about 107F(42c) for several days on and off. My watering routine was 10 gallons per inch (total 4 inch trunk) of tree trunk every 4 days. The soil is mostly sand. But I have compost 1 inch layer on top.

Other reason could be compost tea. I have been adding it every week for 4-6 weeks. I don't make real compost tea, I just soak compost in 5-10 liters of water, let it stay for a week, stir it, and then give just the water to the plant. Now I have stopped it for about a week.

So, I say it is either overfertilizing, or underwatering due to heat. To deal with both problems, I have pushed my watering up, and giving 10 gallons of water per inch trunk every 2 days. Because after every 2 days the top 2-4 inches get fully dry if the weather is hot.

Please help me to identify the issue, and I would love to know the best watering quantity for both hot and cold days in sandy soil.

Below are the pictures of the old leaves tips drying.

Below are new leaves deformed.

Answer 1

As with most issues of this kind, round up the usual suspects.

• Look for insects. You seem to have at least a little insect damage.
• Look for fungus.
• Look to weather, too hot or cold, too wet or dry.
• Look to over/under fertilizing.
• Look to whacky chemicals nearby. Anybody spraying anything?

I'm going to guess the hot weather in your case. But get yourself a small magnifying glass and look at several leaves looking for insects and fungus.

Ordinarily, a tree of this size would not need watering unless you were looking at something like three weeks with zero rain. They have fairly deep roots. To get water to the roots you need to put a lot of water on the surface. Generally, when you do water, you don't want to be putting anything in the water. For example, if you put five gallons of water on the soil near the trunk it likely makes little difference to the tree.

Depending on the nature of the soil, you very likely don't want to fertilize a mulberry. You certainly don't want to be fertilizing more than once per year. You should be sure it is a fertilizer that a mulberry will thrive with. I have had a lot of success with just trimming them and keeping weeds away from the trunk.