University of Vermont
Department of Plant and Soil Science
Summer News Article
CHIPMUNKS IN THE GARDEN
Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont
One form of wildlife some like to watch outdoors, but many would rather not
have in our gardens, are chipmunks. Knowing a few facts about
chipmunks may help prevent them from eating bulbs, damaging young plants, or
causing more serious structural damage.
A wildlife publication from Penn State University provides a concise summary
of chipmunk biology, as well as control methods. From this I was
interested to learn that chipmunk burrows may extend 20 to 30 feet.
There is no soil around the openings because chipmunks carry it away from
the burrows in their cheek pouches and scatter it away from the
openings. The burrows are complex, usually with chambers for nesting,
food storage, side pockets and escape tunnels.
Usually there are two generations of chipmunks borne a year, with two to
five in early spring and again in late summer. So if your landscape
seems to have many, this is why. They may range over about a
half-acre, but only defend about 50 feet around their burrow opening.
Chipmunks gather and store food, often seeds, throughout the year. If
you have seen clumps of sunflowers coming up in flower pots or the lawn, or
small bulbs blooming far away from where you planted them, you can thank a
chipmunk! This is one of their purposes in natural woodlands--
to sow seeds for forest regeneration. Although chipmunks mainly eat
seeds, berries, nuts, insects and mushrooms on the ground, they also can
climb trees to gather these or to prey on young birds and bird eggs.
Chipmunks do not hibernate during fall and winter as woodchucks do, but
remain rather inactive, subsisting on their stored food. You may see
them active on warm, sunny days. In addition to their damage in
gardens, chipmunks can cause structural damage from burrowing under stairs,
retention walls, or foundations. They may kill flowers from burrowing under
Exclusion can be used to keep chipmunks from buildings and some flower
beds. Fill openings at building foundations, fill and caulk openings,
or use one-quarter inch mesh hardware cloth. Cover annual flower beds
with this hardware cloth, at least a foot past the edges. You can
cover the wire lightly with soil to hide it.
Where bulbs may be damaged, if planting a whole bed, first dig out all the
soil. Then line the bed with similar hardware cloth before refilling
and planting. Cover the top with the mesh cloth until spring when the
bulbs emerge. If planting bulbs in individual holes, place some
sharply crushed stones or shells in each hole before refilling. This
will help deter their digging. Such products often can be found, just
for this purpose, at feed and garden stores.
Habitat modification may lessen chipmunk damage. Try not to
continuously connect, through vegetation and plantings, wooded areas with
garden beds and homes. Such areas, wood piles, and debris provide
protection for them, plus their openings are hard to find under such cover.
Spilled bird seed from feeders is a common attractant for chipmunks, as
around my own home. Place bird feeders 15 to 30 feet from
buildings or gardens. Keeping grass cut short around such areas will
provide little cover for them and encourage them to burrow elsewhere.
Taste repellents, such as those for squirrels, can be used for chipmunks too
and may be a good first line of defense. These can be used on bulbs,
seeds, and foliage not meant for human consumption. These need to be
reapplied, can be expensive over time, and generally donít provide complete
control even though
Trapping is an effective means of control around homes and gardens.
Common rat snap-traps are used by some. If using these, place boards
or a box over, with small opening for the chipmunk, to prevent children,
pets, birds or other non-target wildlife from getting caught.
Many prefer to use a live-catch wire mesh trap, then transport them several
miles away so they donít return. While relocating chipmunks is not illegal
in Vermont (as is the relocation of most larger wildlife), it is in some
states. This generally is not recommended, though, as they may not
adapt well or even survive in a new site. Another alternative for
live-trapped chipmunks is to humanely euthanize them. If relocating to
a property other than your own, make sure you have the landownerís
If using traps, a variety of baits can be used including peanut butter,
seeds, raisins, or breakfast grains. Place traps in areas, and along
routes, where the chipmunks are seen. You may want to fix the traps
open a couple days to condition the chipmunks to them, before setting.
Check traps often to remove captured chipmunks and to release non-target
animals such as birds from live traps.
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