This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
I have been observing the controversy regarding the poisonous qualities of Kalmia. I confess I cannot understand why chemistry fails to show that it is a most deadly poison. My earliest recollections are coupled with the aid the boys of my native village gave to the men who drove cattle and sheep across the mountains before the days of railroads. Our village was at the base of the mountain, which was three miles to its summit, and the pike, lined on either side by dense thickets of Kalmia - the especial dread of sheep drovers. The boys of the village were employed by the drovers to assist in keeping the flocks on the pike until the summit of the mountain was reached.
I doubt if a large flock was ever driven across it without the loss of several from eating Kalmia. I have seen them lie down to die before they could be driven from the thickets into the highway. My grandfather kept large flocks of sheep, and I can remember one occasion when a deep snow fell leaving nothing green but the Kalmia, and the flock could not be found until late the following day (being in a very large range). When we found them a very large portion of the flock were dead with the Kalmia leaves in their mouths. They were found in groups about Kalmia plants - in one case five died just where they ate. Within two years my partner in the fruit farm had a valuable heifer in company with a small flock of sheep in a range where he had directed the hired men to cut out all the Kalmia. In a few places the Kalmia had sprouted up, and after a fall of snow looked temptingly green. The heifer was found dead with portions of the Kalmia protruding from her mouth. I could multiply these instances. But it seems to me a direct experiment would convince the most skeptical.
Any one willing to sacrifice a sheep by allowing it to eat Kalmia leaves, could have it demonstrated to his satisfaction that it is a poison, chemistry to the contrary notwithstanding.
Sheep accustomed to the sight of it were never known to eat it except when the ground was covered with snow; but flocks driven by it from the western country, would eat it if permitted.