In addition to their beauty, a selling point for daffodils is that squirrel pests tend not to eat them (squirrels will dig up and eat tulip bulbs and crocus corms); squirrels may, however, dislodge your daffodils.
Another selling point for daffodils is their longevity. The growth of some bulb plants peters out over the years, and the plants die off. But through bulb division and seed production, your daffodils should spread as time goes by. Daffodils can be grown just about anywhere in the U.S., except for some areas in the extreme South.
Because they are early bloomers, daffodils can be grown under deciduous trees. Daffodils get enough sun in the spring (before the trees leaf out) to grow and acquire the nutrients they need for the growing season. But don't plant daffodils under evergreen trees, since the latter cast shade during the entire year and would deprive your daffodils of the necessary springtime sunlight.
Resist the temptation to cut back the plants' foliage after the daffodil flowers have faded and died. As long as the foliage stays green, your daffodils are sending nutrients to the bulbs underneath them. These nutrients will be important for the next year's growth. But when the foliage begins to turn yellow, you can cut it off.
For more on daffodils, see white daffodils.
