Are Dahlias Deer Resistant? What Can You Do To Protect Your Garden?

By Paul Smart •  Updated: 01/17/22 •  6 min read

Are Dahlias Deer Resistant? Dahlias are an extremely popular flower that comes in a broad range of different forms and colors. It produces masses of flowers typically in the hottest part of the year which makes it an ideal plant for the cottage garden. However, if you live in a location where there is a large deer population will the dahlias survive?

Dahlias are considered not very deer resistant according to the New Jersey Agricultural Experiment Station website which rate it “occasionally severely damaged” which is the second-highest rating in terms of deer preference. This means that while Dahlias are not a deer’s favourite food they will definitely require some form of protection.

There are many different ways you can protect dahlias from the local deer population, however, the effectiveness does vary substantially depending upon the methods are used. The only 100% foolproof way to protect your plants is to erect a fence that is at least 8 ft tall as deer are known to be excellent jumpers.

There are academic studies that show that the vast majority of the population can clear a 6-ft fence if required. At 7 ft the number of deer that can successfully jump the fence falls significantly. However, the chances of damage to your fence increases. As such an 8-foot fence is recommended because it acts as a deterrent for deer even attempting to get over the fence. To read more about this click here.

The other way to discourage deer from entering your garden in the first place is to plant things in it they generally do not like to eat such as lavender and rosemary. These types of plants are most effective when they are placed at the outer edges of the garden because it reduces the chances of the deer entering the garden in the first place.

Additionally, the height of the plants can also help to keep the deer out because it makes it more difficult for them to see other plants in the garden that are more appetizing. If they cannot see the plants they want to eat they are less likely to enter the garden.

It is advisable to plant things that they do like to eat closer to your house as your presence in the general area will discourage them from hanging around at least for some part of the day.

Aside from physical barriers and rearranging the structure of the garden there are a number of commercial repellent systems that are available on the market. However, their effectiveness varies significantly depending on the nature of the product. The deer repellent systems that are available can generally be divided into two main categories chemical repellents and mechanical repellent systems.

Chemical Repellent

There are a large number of different types of chemicals that can be used to repel deer. The mechanisms that are used to achieve this usually fall into the category of being fear-inducing, pain-inducing or generally unpleasant smells that the deer do not like.

Of these types of systems, the most effective by far is the fear-inducing products. Most of these products are based upon ingredients such as coyote urine, blood or putrified egg. Putrified egg is effective because it emits a smell that is similar to the odors produced by common predators.

However, studies have shown that even the most effective deer repellents have a limited period of effectiveness which is typically 10 to 12 weeks. Studies have shown that after this period the deer will begin to return to the area and the level of feeding will progressively increase. 

As a result, the only effective way to stop deer is to change the repellent periodically to ensure that the animals do not get acclimatised to one particular type.  As such we recommend purchasing at least two different types of deer repellent.

The two products that we recommend deer out and plantskydd because they are both fear-inducing repellents that is based on different ingredients which means that they will emit different odors that will trick the deer into thinking that there is a new threat nearby. To see the latest prices of these two items on Amazon click on the links.

Mechanical Repellent Systems

There are three different types of mechanical repellent systems which are generally available which are motion activated sprinklers, ultrasonic systems, and things like predator eyes which are devices that are supposed to mimic the eyes of predators at night.

Of these three devices, the most effective is the motion-activated sprinklers based on academic research and also some general experience from people that have purchased these types of products.

However, even the most effective sprinkler systems generally do not reduce activity for very long. Academic studies have shown that using sprinkler systems have a limited effect on the feeding behaviors of a deer over a period of time.  To read more about please click here.  

However, sprinkler systems can still be used as part of your defence system provided they are used sparingly. This means turning them on and off periodically during the year and also moving the position of them in the garden regularly.

If you want to purchase this type of system the one we would recommend is the Orbit 62100 Yard Enforcer because it has a 40 ft detection range and 120 degrees view range.

In terms of ultrasonic systems, there is a body of work that has been carried out by academia, which indicates that these systems are extremely ineffective and do not produce any response in a range of animals which include deer and rodents. We, therefore, do not recommend that you purchase this type of system as it simply will not be effective.

The third common type of deer repellent is predator eyes has very little academic studies done on their effectiveness.  However, I have looked at several products in this area and found the overall consensus from those people that have used the product is that they do not work well and have very little impact on the deers’ feeding habits.

Some of the reviews even provided footage from a night vision camera which showed just how ineffective they were.  One example showed a deer standing next to predator eyes eating the plants that it was supposed to be protecting.

I hope you found this article useful and you have great success with your dahlias. If you have any comments or questions please leave them in the section below.

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Paul Smart