Back Issue
March/April 2001

Deer in Connecticut
• The deer herd in Connecticut has increased from 23 at the turn of the century, to 20,000 in the late 1970s, and is now estimated to be over 76,000.
• Deer browse an average of 5-15 pounds of vegetation per day. Their normal diet consists of leaves, twigs, forbs, acorns, lichens and fruit.
• Suburban deer prefer to browse on ornamental species rather than native plants.
• Forests with deer densities exceeding 20 deer/square mile will have little, if any, natural regeneration. At higher densities, a browse line may develop where all palatable plant parts within six feet of the ground are eaten. Under starvation conditions deer begin to strip bark off small trees and branches.
• Forest understories have become dominated by browse resistant species such as hophornbeam, blue beech and striped maple along with exotic invasives such as Japanese barberry, ailanthus, oriental bittersweet and winged euonymus. Unfortunately, these browse resistant species often have lower economic, aesthetic and wildlife values than the species they displace.
• The damage cause by browsing is not limited to trees. At least 98 threatened or endangered plants are browsed by white-tailed deer.

Limiting Deer Browse Damage to Landscape Plants
by Pamela Weil

Jeffrey S. Ward, a research scientist at the Connecticut Agricultural Experiment Station in New Haven, has done us gardeners a big favor! He recently published "Limiting Deer Browse Damage to Landscape Plants," the results of a two year study involving 269 Connecticut gardeners in 63 towns. The study is of interest to deer-challenged gardeners who will are looking for some general guidelines about how to have both a garden and deer at the same time.

Gardeners in the study listed the plants on their property that were eaten by deer. Based on the degree and severity of this deer browse damage, Ward assigned an index value to each plant. The lower the index value (less than 50), the better the plant will survive in a deer browsed garden. "Plants with low index values above 100 will likely suffer heavy-to-severe browse damage," Ward writes.

Tulips top the deer-delicious list at 368, followed by yew (320), hosta (3214) and daylily (298). This is no surprise to any of us. But there are plants on the low-browse list that I hadn't considered for my garden. Beautybush, for example. I'm going to grow it! And I'm grateful to see the no-so-good rating for lupines as I was planning to buy quite a lot of them this spring! Now I'll invest my plant dollars in something not so delicious to deer.
Our property is foraged by 3 to 6 deer daily. And my experience with deer resistant plants pretty much agrees with Ward's study. I successfully grow monkshood, foxglove, globe thistle, Russian sage, Lamb's-ears and others on his low-browse list. However, I'm surprised to marigolds listed as a low-browse. They're eaten by my deer!

Which brings up a most important fact: There is no such thing as a completely deer-proof plant. Marigolds are eaten in my garden but maybe not in yours (did you plant a smellier variety?). Even daffodils, which are highly resistant to deer browse, were reported lightly browsed by 15 percent of gardeners in the survey.

You can expand your plant palette by exploring each category of low-browse plants. Consider spireas, for example. There are spireas with golden yellow foliage (e.g., 'Gold Flame', 'Gold Mound'), others with interesting crinkled leaves (e.g., 'Crispa') and some with foliage that changes color. Deer don't touch spireas in my garden, so I've learned to plant more of them.

I've also learned to protect shrubs and trees while they are young and especially vulnerable to deer damage. many plants will outgrow the deer, who seem, at least in my garden, to nibble on leaves that are easily reached — neither too low nor too high. A round cage fashioned of wire mesh serves the purpose admirably.

Ward's survey doesn't include every single plant; after all, there are thousands. And some that didn't make his list are garden gems. For example, deer will ignore two excellent evergreens, Siberian carpet (Microbiota decussate and plum yew (Cephalotaxus). And although rhododendron ranks as highly desirable to deer, there are some that will survive quite well. Ask around before planting. And if in doubt, think prickly, highly aromatic (as in herbs), or silver leafed. Plants with these characteristics are usually not browsed.

Pamela Weil, the editor and publisher of Connecticut Gardener, is a Master Gardener certified by UConn's Cooperative Extension System.

List of Plants
Of course, the report includes more information than we can publish here. To order a free copy of the complete list, Limiting Deer Browse Damage to Landscape Plants, write to:
Publications
The Connecticut Agricultural Experiment Station
PO Box 1106
New Haven, CT 06504-1106
email: paul.gough@po.state.cut.us

Annuals and perennials grown as annuals
Unlikely to be damaged
Dusty Miller (Senecio) 22
Alyssum (Lobularia) 30
Vinca (Catharanthus) 38
Forget-me-not (Myosotis) 45
Marigold (Tagetes) 47
Heavy-to-severe browse damage
Impatiens 223
Sunflower (Helianthus) 181
English daisy (Bellis) 180
Dahlia 159
Begonia 151-155
Caladium 145
Zinnia 138
Aster (Callistephus) 131
Gladiolus 126
Geranium (Pelargonium) 119
Flowering Kale (Brassica) 118
Coleus 118
Petunia 105
Cosmos 100
Canna 100

Bulbs and corms
Unlikely to be damaged
Daffodil (Narcissus) 23
Ornamental chives (Allium) 27
Snowdrop (Galanthus) 29
Star of Bethlehem 45
Snowflake (Leucojum) 47
Heavy-to-severe browse damage
Tulip 368
Daylily (Hemerocallis) 298
Lilies 277
Spring-flowering crocus 142
Wood hyacinth (Endymion) 104
Hyacinth 100

Herbaceous perennials
Unlikely to be damaged
Thyme 7
Catmint (Nepeta) 8
Trillium 13
Mint (Mentha) 14
Lemon Balm (Melissia) 16
Oregano 18
Tansy (Tanacetum) 23
Goldenrod (Solidago) 24
Poppy (Papaver) 25
Rubarb (Rheum) 26
Mayapple (Podophyllum) 29
Lavender 30
Lily of the valley (Convallaria) 30
Lamb's-ears (Stachys) 33
Rue (Ruta) 33
Russian sage (Perovskia) 35
Lady's mantle (Alchemilla) 37
Silvermound (Artemesia) 37
Ragged Robin (Lychnis) 39
Yarrow (Achillea) 40
Globe Thistle (Echinops) 41
Foxglove (Digitalis) 42
Monkshood (Aconitum) 44
Tickseed (Coreopsis) 49
Lenten Rose (Helleborus) 50
Heavy-to-severe browse damage
Hosta 314
Golden sunflower (Heliopsis) 275
Garden phlox (P. paniculata) 243
Turtlehead (Chelone) 214
Sunflower (Helianthus) 182
Candytuft (Iberis) 161
Hollyhock (Alcea) 158
Daisy (Chrysanthemum) 158
Black-eyed Susan (Rudbeckia) 154
Shasta daisy (Leucanthemum) 152
Coneflower (Echinacea) 147
Stonecrop (Aethionema) 146
Hisbiscus (Hibiscus) 144
Cardinal flower (Lobelia) 144
Bolton's Aster (Boltonia) 144
Rose mallow (Malva) 143
Stoke's Aster (Stokesia) 139
Aster 133
Joe Pye Weed (Eupatorium) 130
Lupine 130
Balloonflower (Platycodon) 129
Solomon's Seal (Polygonatum) 129
Stonecrop (Sedum) 111
Blanketflower (Gaillardia) 111
Larkspur (Delphinium) 110
Creeping Phlox 108
Bellflower (Campanula) 106
Pasqueflower (Anemone) 106
Blazing Star (Liatris) 100
Gentian 100

Shrubs and Trees
Unlikely to be damaged
Kerria 18
Andromeda (Pieris) 21
Goldenbells (Forsythia) 25
Beauty Bush (Kolkwitzia) 27
Barberry (Berberis) 28
Bluebeard (Caryopteris) 29
Heather (Calluna) 33
Honeysuckle (Lonicera) 37
Broom (Cytisus) 38
Spirea 39
Boxwood (Buxus) 39
Cinquefoil (Potentilla) 41
Shadbush (Amelanchier) 43
Cotoneaster 47
Spruce (Picea) 48

Heavy-to-severe browse damage
Yew (Taxus) 320
Euonymus (Euonymus) 252
Arborvitae (Thuja) 250
Rhododendron 202-239
Rose (Rosa) 201
Hydrangea (Hydrangea) 176
Holly (Ilex) 157-171
Yucca 151
Eastern red cedar (Juniperus) 151
Mountain laurel (Kalmia) 149
Juniper (Juniperus) 149
Hemlock (Tsuga) 144
Willow (Salix) 130
Rose of Sharon (Hibiscus) 120
Crabapple (Malus) 109
Burning Bush (Euonymus) 108
Daphne 104

Connecticut Gardener
P.O. Box 248
Greens Farms, CT 06436
1-800-600-0476
email: editor@ conngardener.com