Last night the temperature got down to 29 degrees here in Michigan. My peonies are all in bud, as are my tall allium. My oriental lilies, while not budded, are tall and growing. I was concerned about the plants freezing, but because I have so many, it seemed impossible to cover them all. This morning at 6 am, with the thermometer at a dreaded 29 degrees, I got the bright idea to run the sprinkler over part of the garden. I’d read how farmers in Florida do the same to protect their citrus crops from freezing during unseasonable cold. The water should be around 50 degrees, right? What could go wrong?
Well, after two hours of an oscillating sprinkler running over the garden, I discovered that now instead of a little frost on my plants they were completely shrouded in ice. Ice dripped from the plant supports, from the leaves, and had formed casings around each peony bud. Yikes. I turned off the water and cracked and removed the ice as best as I could. The outside temperature is now hovering around 34.
The lilies were similarly cased in ice. I closed my hand around the top of each plant to crack the ice which fell to the ground clacking like winter. The lily leaves look bruised and dark; I can’t tell how the peonies will fare. I’m hoping that since the allium are so close to blooming that they will be OK. Maybe they are more cold hardy. Those buds didn’t seem to have any ice on them. Darn it, what have I done?
Of course after this debacle, I looked up frost and peonies, and read that it is the freezing of the dew on the plants that causes the damage more than the temperature alone. That is why most peonies do Ok with some cold, and why covering the plants is important; that prevents the dew from landing on the plants. So I guess I marched right in and created a problem that hadn’t existed on its own. There didn’t seem to be all that much dew last night; the cars in the driveway had ice on the roofs, but none on the windshields; the roof of the house across the street had only a dusting of frost; the lawn had frost patches only. So my watering served to provide the water that would freeze and cause the damage I was trying to avoid. Looks like I really mucked up the situation.
On the other hand, the Michigan State University extension service website describes using sprinklers to protect crops like blueberries and strawberries, and states that this method is effective down to 23 degrees. Huh. They don’t seem to worry about the formation of ice, as the ice stays at 32 degrees and supposedly prevents the plants from getting even colder. They run the sprinklers until the air temperature is above freezing and rising.
So did I cause the problem, solve it, or make no difference in outcomes? No idea. I guess time will tell.
Life is such a learning experience. I did cover one flower bed that had a number of oriental lilies, irises starting to bud, and newly seeded sections where the seeds may or may not be germinating. The rest of my garden I left alone; just not enough old bed linens to make a dent. So there is my controlled experiment: intervention by covering, intervention by sprinkling, and no intervention. The lilies will be the test plants, as they were in all the test groups. I have peonies that I sprinkled and those that I left alone, so those results can be compared as well.
Until today I’ve been restraining myself from going to the garden center to buy plants. I have five flats of annuals under grow lights, and I never did start my dahlias in pots this spring. After one more possible frost tonight I can start setting them all outside. Time will tell whether my peonies, lilies, allium, and sundry other plants in my back yard perennial garden will bloom or not after this cold weather and after my failed attempt to prevent damage. I’ll let you know how it all turns out.
Harriet Anne Squier 