Bloomsz Crocus Bulbs Yellow Mammoth Flower Bulb (20-Pack) If you're searching for a look that's anything but subtle, plant a huge drift of Yellow Mammoth Crocus bulbs. Deer and rabbit resistant. Grow 4-6" tall. Bloom in early spring. Hardy in Zones 4-10 Growing Instructions: Select a spot in the garden that receives full sun to part shade where the soil drains well. Loosen the soil, and plant the bulbs, pointy end up, approximately 3-4" deep and a few inches apart. Tamp down the soil and water well after planting. Foliage should be left to die back naturally as it provides the nutrients the bulb will need to grow and flower the following year. Bulbs may also be planted in containers and tubs at the same depth. Planting tip: For a more natural look, plant crocuses in clusters rather than in straight lines. To achieve a naturalized look, crocuses can also be planted in the lawn. Toss handfuls of bulbs onto the desired area of the lawn and plant them where they fall. Just don't mow the lawn until the leaves of the crocuses have died down.