Deer Country: Report on ‘Deer Out’ Repellent Experiment

Deer Out protected this
tomato plant

How did my experiment with Deer Out, a mint-based deer repellent spray, turn out? 

I posted on April 3 about the spray and said that I was going to use it on selected plants that were not otherwise protected from our local deer herd.

I followed directions and applied the spray multiple times over the summer.  I sprayed seven hostas that previously had been browsed to stem-only status at least twice each summer; a heuchera that has been annually defoliated; one Virginia Sweets tomato plant that I planted in a front-yard flower garden solely for this experiment; and an arrowwood viburnum shrub that deer love to eat so much that they had broken through my barricade of steel posts and plastic deer fencing.

Even though Deer Out directions say it will last 90 days and will not wash off in rains, fine print indicates that it should be reapplied after especially heavy, but non-defined, downpours.  On the average, I reapplied the spray about every four weeks and especially after heavy rains, such as the multiple inches we got when Hurricane Irene passed up the coast last weekend.

I had bought a 40-ounce ready-to-use spray bottle of Deer Out online ($16.99 + shipping), and it became clear early on that the bottle would empty long before the summer ended, even though I was spraying only 10 plants.  So I ordered a 32-ounce bottle of concentrate ($34.99 + shipping) to complete the summer spray program.  When diluted, the concentrate makes 320 ounces of ready-to-use Deer Out (11¢ per oz.), a saving of nearly 75% over the first ready-to-use bottle (43¢ per oz.).

Deer Out protected this heuchera (coral bells)

If a picture is worth a thousand words, let’s keep this report relatively short and look at photos I took last Wednesday of the plants I sprayed with Deer Out this year.  Let’s look at them in the order I come to them as I walk from our garage with the Deer Out spray bottle in hand:

Deer Out totally protected the Virginia Sweets tomato plant.  Deer hoof prints abound in the mulch around the tomato plant, which was browsed at least once before I first sprayed.  A July thunderstorm toppled the tomato cage because the indeterminate plant had become top heavy, so I pruned the plant severely, and the deer didn’t.  Score +1 for Deer Out.  Brown marmorated stink bugs totally devastated the fruit on this plant so obviously they were not repulsed by Deer Out.

Deer Out totally protected the heuchera (coral bells), a volunteer that popped up the spring after I moved the parent plant to our fenced back yard because it had been browsed so often it appeared to be dying.  In 2009 and 2010, deer browsed nearly every leaf of the young heuchera, leaving only stems.  This year the plant grew and flowered and deer didn’t touch it, though hoof prints indicated they had explored the narrow garden by our front porch.  Score +1 for Deer Out.

Deer Out protected these hostas

Deer Out totally protected our seven hostas, which for years had grown in a bed between our front sidewalk and the wall of our garage and which annually were browsed at least twice.  In defeat, in 2010 I moved them 25 feet or so to the south so visitors wouldn’t ask me what kind of plants I was growing that had only leafless stems.  This year, all seven plants, protected by Deer Out, grew, flowered, and went to seed, though mulch around them was churned several times by deer hoofs.  Several hostas flowered twice, a truly remarkable event here in Deer Country.  Score +7 for Deer Out.

And the final plant—the arrowwood viburnum shrub?  I sprayed it with Deer Out every time I sprayed the other plants.  Even though deer had broken my barricade of steel posts and plastic deer fencing to get to the viburnums, I left the remains of the fence in place during the experiment, which protected one side of the shrub.  By late spring I was feeling the Deer Out was protecting the arrowwood.  But several weeks ago, when does started bringing out their fawns to graze, I discovered twin fawns resting inside the barricade after some heavy browsing or nursing.  Alas, as the photo indicates, Deer Out failed to protect the viburnum, which was browsed just as heavily as the unsprayed arrowwood to its left.  Score -1 for Deer Out.  And, yes, I did smile when I saw the two spotted cuties lounging inside the wrecked barricade.

Deer Out failed to protect the
arrowwood viburnum on the right

With a success rate of 9 out of 10, I’ll judge Deer Out as “very effective.”  I have plenty of the concentrate left, which I plan to use on selected plants next year. 

Why was this spray effective?  I can think of several possible answers.  Perhaps because deer don’t like to eat plants that smell like mint.  Perhaps because I reapplied the spray regularly and generously, especially after downpours and didn’t wait for “90 days” to pass before re-spraying.

And why did the deer browse the arrowwood viburnum?  Perhaps because the shrub was farthest from our house and more deer approached it and one of them happened to be a York Mint candy fan.  Perhaps our herd loves arrowwood leaves so much that neither fence nor spray would deter them.  Perhaps I’d have a more satisfying answer if I could consult with a deer psychologist.

Will Deer Out protect your plants?  The only way is to try it.  But deer “tastes” differ from area to area and herd to herd.  A friend, Ella R., who lives just a few miles from us, sent me an email saying she used Deer Out on her hostas this year and local deer browsed them to the ground.

We’ll most likely have a frost within the next four to six weeks, so I’ve decided last week’s spray application was the last for this year.  I’ve already bought a bundle of steel posts and a roll of welded wire and this winter will build a “proper cage” around the viburnums.  I plan to win this battle with the browsers.

Yes, this is Meadow Glenn, in the heart of Howard County, Maryland, Deer Country, where shrubs and trees are caged and deer run free.  And, yes, this is Meadow Glenn, where next year I’ll be spraying Deer Out once again.

To read my first posting (April 3) about the Deer Out experiment, CLICK HERE. To read my first update (August 3), CLICK HERE.