Voles are small mammals that measure between 4-8.5" from head to tail. Often called field mice, these creatures destroy trees, shrubs, and other plants by gnawing on their trunks or eating their root systems. Spring bulbs can be especially susceptible to these attacks.
Signs of voles include 1-2" wide burrows and quarter size holes around your plants. Also look for 1/8-3/8" gnaw marks around plant stems that are formed at various angles. If your plant is leaning over and drooping, lift its root system from the ground to see if the roots have been eaten. If many of the above symptoms are present, then you probably have voles.
Luckily, Soil Perfector from Espoma can aid you in protection from these pests.
Soil Perfector provides a permanent physical barrier to voles and is made from a naturally derived, ceramic mineral that is kiln-fired at temperatures in excess of 2000° F. This process creates a durable, lightweight, abrasive granule that voles are naturally discouraged to dig through. Soil Perfector is non-toxic and will not physically harm the voles. Furthermore, Soil Perfector will not break down or degrade in the soil so one application is all you ever need.
Dig a hole 2-3 inches deeper than the specific depth recommended for your bulb, then line the bottom of the hole with 2-3" of Soil Perfector. Set the bulb in your hole and fill the remainder with a minimum of a 3" lining of Soil Perfector. Backfill the remainder of the hole with a mix of 50% Soil Perfector and 50% previously removed soil.