Answer: Weigela "Java Red" is sometimes described as a dwarf form of the shrub, expected to reach only about four feet tall so your plants may be within their normal size range. In general, weigela does best in full sun with an evenly moist yet well drained soil of at least average fertility. It is not particularly demanding in its growing conditions, although maintaining a layer of organic mulch over the root zone and an early spring application of compost and/or a granular multi-purpose fertilizer according to the label instructions might give them a boost. You might want to check with your county extension and run some basic soil tests just to make sure there is nothing unusual happening there. The test results will also tell you what nutrients need to be supplemented and by how much.
The other possible reason for less growth than expected could be that the roots have not expanded beyond the original planting holes and thus the plants are stunting themselves. This could happen, for example, if encircling roots were not directed outward into the native soil, or if smooth sided planting holes were dug into a heavy clay soil.
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