Semi-dwarf peach not growing

I planted a semi-dwarf Elberta peach about 6 or 7 years ago. Every year we get about the same number of peaches (25-30). They are good quality. However, the tree has not grown more than a couple of inches since we planted it. It leafs out normally, the branches grow an inch or two and stop growing. I water once a month in the winter, once a week in the spring and fall, and twice a week in the summer. I use a liquid, spray-on fertilizer just before and during its expected growth, yet it doesn't grow. Please help me and my tree.

Because your tree is a semi-dwarf peach, it will grow more slowly that standard-size peaches. The production of fruit also limits its growth. If you would like to see more growth, you might try removing at least half the fruit in May next year. Fertilizer with a high nitrogen analysis will also stimulate vegetative growth (at the expense of fruit production), but don't apply such fertilizer after mid-July. Applying nitrogen too late may stimulate growth that won't hardened for winter before your first frost.

Your watering schedule seems adequate, or perhaps too often, but your watering frequency should be determined by your soil type. How much water do you apply with each irrigation? It is important to apply water equivalent to about 80% of evaporation-transpiration (ET - water evaporated from a wet surface and transpired through plants). The "potential ET" rate is determined by measuring water evaporated from a "standard evaporation pan." This data is available on the Weather Page of the NMSU/College of Agriculture World Wide Web Page. (This page, http://weather.nmsu.edu, is maintained by Dr. Sammis at NMSU.)

The quantity of water to apply should be 80% of that reported as evaporated (in inches) times the area of the absorptive root system times the number of days since the last irrigation. The area of the root system is (for your tree) probably a circle with a 5 to 10 foot radius around the tree. The water should be applied over this entire area (except for about a 1 to 2 foot radius next to the trunk). Since only the surface dries quickly, deeper water remains longer, so watering once a week or less should be all that is required. The soil type determines the frequency of irrigation because sandy soils hold less water than clay and should be watered more often. You can determine when to irrigate by probing the soil with a screw driver (long blade) about 3 to 5 feet from the trunk. After withdrawing the screw driver from the soil, feel the blade. If it is dry (not cool), it is time to irrigate. If the blade is cool or you can feel moisture, you can wait to irrigate. Test a few days later. It may take a few weeks for the tree's root system to adapt to a new irrigation schedule, so change gradually.