• Choose bulbs that readily multiply by themselves. These include crocus, squill (Scilla), glory of the snow (Chionodoxa), most daffodils and winter aconite.
• Plant the bulbs where they’ll be happy. Match the site to their preferences. This increases the odds that the bulbs will multiply and spread.
• To naturalize bulbs in a lawn, choose bulbs that flower early, and make sure you won’t mow the lawn until later in the spring. This gives the foliage time to build up the bulbs’ reserves and die down before the grass is cut.
• Dwarf bulbs do well in grass that is not very vigorous, such as a partly shaded area. Examples are scilla, chionodoxa and crocus.
• Create the natural look yourself. At planting time, toss handfuls of bulbs into the air and plant them wherever they land. Or plant groups of 5, 7 or 9 bulbs in random spots throughout the lawn or garden.

From Horticulture Magazine