Q: Back in November I planted 300 spring bulbs in my garden. Now I am concerned that I planted them upside-down. Will they grow correctly or must I dig them up and replant them?
A: You can lay to rest your fears that the leaves will grow downward until they are exhausted. Plants have a remarkable array of abilities to grow toward or away from a stimulus. Plant scientists call it tropism. You have probably seen indoor plants that seemed to ‘lean’ towards a window to get sunshine. The orientation of the leaves toward the light is called phototropism. Plant roots grow towards gravity. That is called geotropism.
Fortunately for you, bulb foliage is negatively geotropic. It will grow away from gravity and will emerge from the earth on schedule next spring.
Fortunately for me, in the course of researching your question, I found other interesting “tropisms”. When sunflowers follow the sun as it travels across the sky each day, they exhibit heliotropism. Roots that grow towards water are hydrotropic. Vines that wrap around any surface they touch are thigmotropic. When a bean vine creeps along the ground toward the shadow of a vertical pole, it shows skototropism.
Did you know that bulbs can even move themselves through the soil? Several bulbs, like crocus and tulips, have contractile roots which pull a bulb slowly to the most favorable depth in the soil. It is conceivable that even if you did plant the bulbs upside-down, they would slowly right themselves as the years pass.