Answer: Some amaryllis (Hippeastrum) seem to grow on their own schedule regardless of the gardener's efforts and some do produce abundant foliage prior to blooming. Unfortunately, it is impossible to tell you exactly why yours haven't bloomed yet.
However, here are two possible reasons for failure to bloom. One is that the bulbs are simply not yet of mature blooming size. If this is the case, you will need to keep them growing as vigorously as possible all season and hope that they mature enough to set buds for next year.
The other possibility is that putting the bulbs into full foliar growth before seeing the flower buds has caused the buds to either rot or abort. This can happen if the bulbs are over watered soon after planting. Generally a newly started, dormant amaryllis bulb should be watered lightly to settle the soil at planting and then kept nearly dry (just barely damp) until the bud shows. This is why some authorities suggest syringing the bulb at first, rather than watering the entire soil mass. Once the roots are definitely established and the bud emerges from the bulb it is time to water it regularly, keeping the soil moist but not soggy.
In either case, you should keep the bulbs in active growth for the remainder of this season, rest them this fall and hope they come into the normal bloom cycle for next year.
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