DESIGNING FOR DEER RESISTANCE: COMBINING FLORA WITH FAUNA

By: Jeff Chorba

With their complexity, our forests have sustained the lives of plants and animals for many years without any significant problems. humans, and their ongoing quest to expand their range, have altered some of natures balances, one being the ratio of forest land to open land. Because of this, wildlife living within the perimeter of this expansion has had to become "urbanized", seeking out food and shelter in the midst of confined city parks, residential developments, and industrial parks. These animals are forced to adapt to people, noise, and pollution. Many animals get struck by cars, chased by dogs, and sometimes starve to death. Even in rural areas the density of the deer population has been rising. Smaller animals such as squirrels, rabbits, and chipmunks, for the most part, interact in these environments without much infringement upon people. Deer, however are not as discreet in their manner of living. They destroy an innumerable amount of garden plants throughout our neighborhoods, causing much grief to home gardeners and commercial businesses.

Through my years of designing and planting landscapes in northeast Pennsylvania, I have observed which plants tend to be deer resistant through all seasons. One thing I would like to stress is the term "resistant". Resistant plants are those that are, for the most part, not bothered by deer under most conditions. In my opinion, there are no plants that are deer proof! I have seen plants that have been proven to be toxic to most animals, including deer, eaten by deer under extraordinary winters. With this in mind, it is important to know that one should set goals to try to design and plant landscapes knowing that there will always be some loss of plants.

A plant's deer resistance can be determined by how often or severely plants are eaten during moderately harsh winters when the deer's food supply decreases. Usually plants that are soft to the touch and high in water content are the first to succumb to damage. From my experience, I have seen that deer usually like to eat the tender, flower buds of plants first. Roses (Rosa) and rhododendrons, (Rhododendron) if available, are the first to get eaten. As these food sources diminish, deer resort to plants that are not as palatable, these include forsythias (Forsythia x intermedia) and chokeberries (Aronia arbutifolia). I have found that for the most part plants with thorns or spiny projections turn deer away. Colorado Spruce, (Picea pungens) Barberry, (Berberis) and Holly (Ilex) are all perfect examples of this.

Flavor is another factor which can control deer browsing. Plants with a pungent taste will almost always survive a deer's visit. Marigolds appear to prove this. Boxwoods, (Buxus sempervirens) although marginally hardy in northeast pennsylvania, have been proven deer resistant due to their strong flavor.

A plant can have a certain degree of resistance because of its architecture. A good example would be a crabapple (Malus) tree. Although the foliage is very enjoyable, if the deer can't reach the leaves due to the height of the canopy, the plant will thrive and go untouched.

Controlling deer can also be helped by using design techniques that attempt to divert deer traffic away from precious plantings. If you are fortunate enough to have substantial changes in grade on your property, you can create sunken or raised plantings by using boulders to retain the earth. Deer do not like to climb even small cliffs if they do not have to. If your property is large enough, large mass plantings of naturalized shrubs along the perimeter will help keep deer fed without nibbling on your prized plantings closer to the house. On a smaller scale, you could plant something like lettuce as far as possible from your garden to feed hungry visitors before they move closer.

Designing with and planting deer resistant trees and shrubs is the best way to avoid deer problems. From a design standpoint, adhering to a selected few plants can make landscape designing even more challenging. I think there are a lot of plants that have very high merit in the industry that should be used more. Unfortunately, out of the many lists only a handful are deer resistant. In some ways this method can actually make parts of the design process easier for the fact that it limits your choices dramatically. This streamlining does not make up for the loss in variety, texture, and bloom, which can be very critical to some clients. With extra planning, the use of structural features can help to fill this void. I find stone to be a very good textural element that is available in many forms and very economical; especially in northeastern Pennsylvania.

Most any type of ornamental tree can be used without concern for deer damage. The only thing that is important is that the tree should not be low branched. Low branches are easily reached and can detract from the overall appearance if they are damaged. In the spring, deer can damage the bark of a young tree by rubbing their antlers up and down the trunk. One reliable way to prevent them from doing damage is to use tree wrap. This should be installed in the fall and left on until around June. It is a good idea to remove this for the growing season to allow for trunk expansion and prevent insect or fungus damage.

There are some deer resistant shrubs that I rely on to make a statement in the landscape. Through color, texture, and habit you can create many different effects even with a limited selection of plants. Red Japanese barberry (Berberis thunbergii var. atropurpurea) is a great low growing plant that can be used in a border or add that little splash of color in a rock garden. Inkberry (Ilex glabra) is one of the toughest, most versatile plants I can think of to use in the landscape. I prefer to use the cultivar `Shamrock'. This inkberry stays short cropped and keeps its foliar density even with age unlike the straight species. It is a broadleaf evergreen with rich, dark green foliage that stays free of insect and disease problems year round. If you need a handsome, evergreen specimen, a Swiss Stone pine (Pinus cembra) is the perfect addition to your landscape. Swiss stone pines grow about 8" a year and maintain a tight, pyramidal growth habit. I cannot think of another pine that has such a deep green color and as resistant to pests as this plant. Mountain pieris (Pieris floribunda) - sometimes called "Mountain Andromeda" is an excellent massing plant that has creamy white flowers in the spring. This broadleaf evergreen can be difficult to grow under some conditions. I have found it to do best in a slightly acid soil in a north west exposure. It absolutely dislikes alkaline soil and full sun. I find Mountain Pieris works best in naturalistic plantings that have a good loamy, woodland soil.

Spireas can offer a pleasant touch of color in that hot, dry location of the garden I like to use Vanhoutte Spirea (Spiraea x vanhouttei) for large masses that can screen unwanted views and brighten up a dull corner of the garden. Vanhoutte spireas is one of the tallest spireas that you can plant. Vanhoutte spireas display white flowers in early summer for about two weeks. Anthony Waterer Spirea (Spiraea x bumalda "Anthony Waterer") is a fine plant that has lavender colored flowers that bloom for at least 3 weeks. This spirea tends to bloom in mid to late summer non-stop till frost. There are too many other species of spirea with great merit to list here. For the most part, all Spireas are deer resistant and are very reliable plants.

After I have designed the main concept of the landscape with woody ornamentals, I like to incorporate small herbaceous plants that add a delicate richness in the garden. There are many species of ferns both native and exotic that are deer resistant. Most ferns like to be grown in at least a half shady location in a good loamy soil. One problem with ferns is that they lack winter interest. It is a good idea to plant a woody plant nearby to take over during the winter months.

Ornamental grasses can offer a special textural element which persevere through four seasons. They are also one of the most economical plants I use. Miscanthus and Calamagrostis are two common grasses available at most nurseries and are very reliable. In most cases, grasses prefer to grow in sunny locations where the soil is well drained. Most grasses actually prefer poor soil conditions.

Through proper planning, plant selections, and management, the ongoing problem of deer damage to our valuable plants can be lessened. There should be some tolerance to a certain amount of damage to plants in areas of high deer population. Having low cost plants in strategic areas can fulfill a deer's appetite before they start nosing around your prized plants.

Choosing deer resistant plants is the best way to avoid problems. Experiment with a variety of plants in your area to see if they are bothered. Deer are definitely different in what they eat from area to area. Also, regardless of the pallet of plants to design with, it is always possible to end up with an interesting landscape with four seasons of interest.

I think that there should be more research on how to control deer populations more efficiently and accurately. Topics dealing with wildlife control are very sensitive and should be looked at with and open attitude. I consider myself a naturalist and think hunting is a viable way to keep populations intact. Respect for nature and its systems should be our number one concern. Working along with nature will prove to be a more stable way of gardening so future generations can enjoy our earths flora and fauna.

BIOGRAPHY

Jeffrey Chorba is a Landscape Designer from Beach Lake, PA and has completed the Landscape Design certification at the Morris Arboretum of the University of Pennsylvania. He has worked at designing deer resistant, residential and commercial landscapes in NE. PA He also manages a computer service which provides landscape and horticultural information to landscape professionals and the general public.