A Few Thoughts about Deer

Most of us are aware that deer have become a tremendous problem in regard to landscape plantings throughout the northeast. Mainly because logging operations are giving them a lot more winter browse, the deer population in New England, especially in southern New England, has grown considerably. This, combined with the fact that many housing developments are going up in wooded areas, has led to problems with deer destroying many landscape plantings. Here at Summer Hill, we have had tremendous problems with deer ever since we first started the nursery, and over the years, we’ve learned quite a bit about deer — the hard way. In fact, deer damage is one of the reasons we decided to stop growing field-grown material. Our losses at certain times were 100% of certain varieties.

In controlling deer damage, repellents can work, and we have used Arasan 42S (Thiram) with good results under certain circumstances. However, if deer are hungry enough, they will still eat plants that have been sprayed with repellent. Since I wrote this paragraph a few years ago, we have started using Bobbex — a fairly new repellent that seems to work quite well. Whether “our” deer will get used to it and render it ineffective, only time will tell. Human hair will work as a repellent but only for about a 3 foot radius around the hair ball. The most common method of using human hair is to put a handful in a silk stocking and tie it on the plant. In order to be effective on a large plant, a number of hair balls have to be placed and, once again, their effectiveness, if the deer are very hungry, is doubtful, not to mention the aesthetics.

Also, we have used soap (we think Irish Spring is most effective), cut into pieces and tied to the plants. As with human hair, it seems effective for about a 3 ft. radius but can be ignored if the deer are starving — especially on a preferred browse. Fences are also not the answer as they would have to be at least 10 feet high which makes no sense for a homeowner. My feeling is that in areas with a large deer population, the best answer for the homeowner and landscaper, working for the homeowner, is to use species of plants that are not preferred food sources.

Why do deer eat some plants and not others? I feel the answer to this is, not so much the taste of the material but rather the nutritional value. Deer can tell which plants have more nutritional value for them. They will eat the most nutritious plants first; but after these are eaten and there is nothing else, they will go to plants that will not supply them with as much nourishment but will at least fill their stomachs. Then, if there is nothing else, deer will eat sticks and other items with practically no food value in order to put something in their stomachs.

One factor we must remember, and it is probably the most important to remember in combating this problem, is that deer prefer plants that are well fertilized. The nitrogen that we put on our plants to make them grow and look vigorous enhances their nutritional value for the deer. Deer will eat certain species that they ordinarily leave along if these plants have been heavily fertilized. We’ve had examples of this when pines that are ordinarily immune to deer damage are planted out after they had been in the container area and heavily fertilized for a couple of years. They were decimated during the first winter. It seems to take two to three years for this enhanced nutritional value to leave the plant. What I am saying is that homeowners, in areas of high deer population and resulting landscape damage, probably should not fertilize their plants, with the exception of the few plants I will mention later that deer seem to leave alone under all circumstances. The plant material in their gardens may not look as fine because it has not been fertilized, but it should still be there in the spring, instead of producing venison.

As you would expect, most deer damage occurs to evergreen plants. In general, most deciduous shrubs and trees don’t have much damage from feeding through the winter. Some small branches may be browsed but usually there is little damage that could destroy a plant. Rubbing of antlers on small trees can cause most of the severe damage for this type of plant. Keeping this in mind, I will go through some of the major groupings of plants and list what our experience has been regarding deer damage. Deciduous shrubs not mentioned probably are not bothered much.

The information below comes from the nursery and the gardens at my home. The observations at my home are probably more valuable as the plants there are out in the open all winter, whereas the nursery plants are protected in quonsets.

Abies — Deer like Balsam Fir.

Evergreen Azaleas — Deer love them — some varieties more than others. We actually had deer go into a covered quonset with just the doors open, walk past Azalea ‘Blaauw’s Pink’ that were at the end of the house and go to the middle to eat Azalea ‘Mother’s Day’. This is not to say they wouldn’t have eaten the ‘Blaauw’s Pink’ after the ‘Mother’s Day’ were finished. This was inside a covered quonset!

Deciduous Azaleas — They will eat the buds and the young wood.

Calluna — These will be eaten to the ground.

Cedrus — The deer will eat them as high up as they can reach, including wood as thick as a pencil.

Chamaecyparis — All varieties are susceptible to deer damage, especially C. obtusa forms.

Cornus florida — They will eat the tender tips.

Cornus species — Deer will eat wood of shrub forms.

Cotoneaster — In our experience, this is not a preferred genus; however, they will nip them when hungry.

Cytisus — We haven’t had enough planted out to be sure, but it does not appear to be a favorite browse.

Euonymus — Deer love euonymus, and it is probably the first plant they will go to — even before Japanese Yews.

Hamamelis — They have eaten lower limbs on our H. ‘Arnold Promise’.

Hydrangea — The tips could get nipped — not tremendous damage however.

Ilex — If not fertilized, they tend to leave ilex opaca alone. However, the Blue Hollies and ilex crenata forms are most definitely a favorite browse — one of the first things they go to in the nursery.

Juniperus — Junipers are quite variable as to variety as far as preference. In our experience the horizontalis and communis forms are preferred more than the chinensis forms. They will nip the chinensis forms when hungry, but the damage we’ve received here has not been too severe. They really appreciate finding some nice procumbens ‘Nana’. They eat it practically to the ground — wood and all.

Kalmia latifolia — Mountain Laurel is supposed to be poisonous to deer, at least some people think so. If this was the case, we wouldn’t have any deer in this area, because they will completely strip laurel plants of all foliage. Nutritional value probably isn’t too great on non-fertilized plants since they generally leave the wild plants in our woods alone until late in the winter when there is not much else available.

Magnolia — The deer will eat the flower buds as high as they can reach, especially M. stellata.

Rhododendron — These are a mixed bag when it comes to deer’s preference. I think they will eat any of the large leaf forms, especially if fertilized. However, they tend to leave ‘Roseum Pink’ and ‘English Roseum’ alone, preferring the varieties with some ‘fortunei’ blood such as ‘Janet Blair’ and ‘Scintillation’. ‘Cunningham’s White’ and ‘Chionoides’ are also extremely susceptible to deer damage. In our experience, they haven’t done too much damage to small leaf varieties although they will eat them if they are hungry enough. We had some damage to ‘Wilsoni’ and ‘Dora Amateis’, but I can’t remember them ever bothering ‘P.J.M. Hybrid’. (I wrote this 15 years ago. Since then, we’ve had all our small leaf rhododendrons, including ‘P.J.M. Hybrid’ completely stripped.)

Picea — Deer will eat Picea glauca and Picea abies but only if desperate. I have never seen damage on Picea glauca ‘Conica’ or Picea pungens; however, Picea omorika is almost a favorite browse.

Pinus — They will eat pine but usually only if fertilized and if they are really

Thuja — One of their favorite plants, up North the type plant, Thuja occidentalis, is a favorite browse of deer during the winter, and deer yards are usually situated in areas with a lot of “White Cedar”. Interestingly enough, when we grew arborvitae in the field, the deer would completely ruin ‘pyramidalis’ before they would start attacking the ‘Nigras’. Whether this was because of nutritional value or taste, I have no way of knowing.

Tsuga — Hemlock, also, can be quite popular on a deer’s menu although I believe this is one that becomes far more susceptible when fertilized.

By now you may have noticed I have skipped a few, only a very few, genus and species, and these are the ones I consider fairly immune to deer damage. We have seen practically no damage on the following plants here at Summer Hill.

EVERGREEN SHRUBS IMMUNE TO DEER DAMAGE

Buxus — I have never seen deer touch boxwood — the odor?

Ilex opaca

Leucothoe — These seem to be quite immune — others have told me they’ve seen heavy damage to Leucothoe but I’ve never seen it here.

Myrica — Deer do not seem to like Myrica pensylvanica very much; however, they will eat tips of Myrica gale in tough winters.

Picea — As mentioned before, most spruces are okay under normal conditions.

Pieris — I have never seen any damage to Pieris.

Pinus — Mugo Pine seems very immune — others are fine if not fertilized.

Sciadopitys verticillata — Those big, fleshy needles look as though they would be very tasty, but evidently not. I’ve seen branches where they have tried a bite but that was all.

I am sure most of you reading this have had your own deer horror stories and have some favorite plants that you feel are suitable for areas of heavy deer damage. As I feel this is going to be an ongoing problem here in the northeast, I look forward to exchanging ideas and opinions with you. For those of you that are new to the problem, I hope this has been of some help.