Answer: There are only a couple of reasons for daffodils not to bloom. One is overcrowding (doesn't sound like this is the case with yours) and the second reason is that the leaves were removed from the bulb too soon. Bulbs need their leaves to manufacture and transport energy back to the bulbs for the following year's flower display. If you cut or mowed the leaves off before they yellowed and died back on their own, you interrupted the process of storing energy. As a result, the bulbs put out leaves but didn't have any reserve energy to produce flowers. Allow the foliage to die down naturally before mowing and you should have lots of flowers next spring.
Best wishes with your garden.
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