Q. Here is one of two kumquat trees that I am trying to grow. As you can see it is not working. I feed and water them what is the problem? Can you help? Or should I discard?
A. The issues on the other picture could be related to a mineral fertilizer problem. This one could be the same but with the leaves gone it is hard to tell.
It also might be related to whatever soil amendments you put in the ground when you planted the trees. But I am pretty confident it has to do with the soil, fertilizer issue or irrigation.
It does not help much that they are surrounded by rock mulch. Let’s handle one at a time. Make sure the tree was planted in your soil at the same depth it was in the container. If there was some extreme cold weather, it might also be cold weather damage if you did not see this before it got real cold.
Irrigation. Irrigations should be generous but not frequent. A tree that small can get by with ten gallons of water at each application. If these are on drip emitters you should have enough emitters or run the minutes long enough to deliver ten gallons at this size in its life. This time of the year once a week is often enough. When you start to see new growth, bump it up to twice a week with the same volume of water each time.
Fertilizer. Go down to Plant World Nursery on Charleston (they are the only nursery I know of in town that carries this) and buy a one pound container of iron chelate fertilizer. If you ask for Doug, Brian or any of the main staff they will direct you to the right one since I recommend it a lot. They even have my name on the label now so people will believe them when they direct them to this product.
For each tree mix about two or three tbs in a one gallon container, stir it and distribute it around the base of the tree where the drip emitters are. Water it in with another gallon since it is sensitive to light. Get some rose fertilizer (like Miracle Gro type) and use it on the kumquat or get some fruit tree fertilizer stakes and put the fertilizer under the rocks or drive two stakes close to the emitters. I think the Miracle Gro is better. Fertilizers are salts. Keep all fertilizers at least 12 inches from the trunk when applied.
Mulch. If this were me, I would pull the rock mulch back a couple of feet and put down some good compost (don’t buy cheap stuff) and lightly dig it around the trees from the trunk to a distance of about two feet from the trunk. I would cover the area around the tree in wood mulch but not bark. Keep wood mulch six inches away from the trunk so that it does not cause the trunk to rot if it gets wet. Older trees it doesn’t matter.
Lets see if this works for you.