Planting flower bulbs in the fall often sets up a dilemma for gardeners, as squirrels are natural foragers and view the newly buried bulbs as a potential food source. Rodents excavate bulbs for two main reasons: the high starch content of certain varieties offers a concentrated energy source, and the freshly disturbed soil acts as a clear visual cue that something has just been buried. This foraging behavior, which peaks in the fall as squirrels prepare for winter, means that any soft, newly planted bulb is highly susceptible to being dug up and either eaten or cached.
Bulbs Squirrels Actively Seek Out
Squirrels are highly attracted to bulbs that are soft, starchy, and lack natural defenses like bitter compounds or toxins. These palatable varieties offer a quick and substantial source of carbohydrates, vital for the rodents’ energy reserves, especially leading into colder months. The most common and highly sought-after bulbs are tulips, which are frequently the first targets in any newly planted garden bed.
Crocus bulbs are another variety squirrels readily seek out and consume, often due to their small size and ease of excavation. Hyacinths, with their substantial, fleshy structure, and certain types of lilies are also frequently targeted for their nutritional value.
A tell-tale sign of foraging is the presence of small, conical holes in the soil, the result of the squirrel digging straight down to retrieve the bulb. Sometimes, the gardener will find the bulb itself lying on the soil surface, often with a single, characteristic bite mark taken out of it.
Bulbs That Squirrels Avoid
A number of popular spring-flowering bulbs are reliably avoided by squirrels because they contain compounds that are distasteful or toxic to rodents. Daffodils, which belong to the genus Narcissus, are a prime example, as they contain the toxic alkaloid lycorine and other bitter compounds that cause them to be rejected immediately upon tasting.
Alliums, ornamental members of the onion family, are also highly resistant to squirrel damage due to their pungent, onion-like aroma and flavor. Other varieties that contain toxic compounds include Snowdrops (Galanthus) and Winter Aconite (Eranthis hyemalis), which contain cardiac glycosides that are poisonous to animals. Fritillaria, especially the Crown Imperial variety, is known for a musky, skunk-like odor that squirrels find particularly offensive. Grape Hyacinths (Muscari) are also generally left alone because they contain saponins and other bitter compounds that make them unpalatable.
Practical Methods to Protect Your Plantings
When planting vulnerable varieties like tulips, gardeners can employ physical barriers to prevent rodents from accessing the bulbs. One effective method involves placing a layer of hardware cloth or chicken wire directly over the planted area and securing it with stakes or rocks. A small wire cage can also be created and placed around the bulb in the planting hole to provide a complete enclosure.
Managing the planting depth and soil is another practical strategy to reduce vulnerability. Planting bulbs one or two inches deeper than the recommended depth can deter squirrels, as they are less inclined to dig far below the surface. After planting, firmly tamping the soil and covering the area with a thin layer of mulch or groundcover helps to hide the visual cue of freshly disturbed earth.
Repellents that target the squirrel’s sense of taste and smell can also be used as a deterrent. Sprinkling crushed oyster shells or sharp gravel into the planting hole creates a gritty texture that discourages the animal from pawing through the soil. Applying commercial or homemade repellents containing capsaicin, the compound found in hot peppers, to the soil surface can also discourage digging, although the application must be repeated after rain.