In wet climates, many of the bulbs would rot in humid summer conditions. But in our sunny, dry climate, bulbs will often return, and even improve year after year, forming dense clumps of color from a single plant. For these naturalized bulbs, home Gardeners must think ahead and anticipate that the compact bulb dropped into the earth represents an investment that can pay dividends for years. These groupings of bulbs can be divided, much like any other perennials. To ensure that bulbs will flower year after year, try to site them in an optimum microclimate.
Daffodils tolerate more shade and like lots of moisture.
However, crocuses, tulips and alliums like lots of sun and heat. Like any perennial, bulbs do best in amended soils, in sites that are not too extreme in sun exposure, dryness or traffic. If your bulbs are not blooming prolifically after a couple of years, they may need more nutrition. Add compost or commercial dry-bulb fertilizers when the bulbs are dormant. Or give the leaves a light feeding with half-strength fertilizer such as Peter's Blossom Booster after flowering is done, but before the foliage begins to turn brown.