I have attached a short article about a red spot disease identified for the first time on peonies in Chile. I checked with Andrea G, and she told me, yes, indeed, this disease occurs both in Alaska and Oregon. This past summer, we all noticed some distinct red lesions on the stems and dark red spots on leaves. Now we know what it is!
A grower near Delta brought in roots of peonies that were riddled with wireworms (larva of click beetles). It is the first time we have ever seen them inside the roots. We contacted growers and root sellers in New Zealand, Michigan, Missouri, Oregon, Maryland, Holland and all over Alaska. Not one person has seen wireworms in peonies before even for those growing peonies for 30 years and more. They are well known in Alaska where people grow potatoes and grasses. In the lower 48, they attack a lot of different kinds of root crops. The grower had tilled an old field that contained a lot of grasses, and we suspect the wireworms (that love grasses) were left over after the tilling. Once the grasses were gone, the wireworms lost their usual food source and chowed down on the peony roots. The lesson here is, if you are tilling in an old hay field or an area with a lot of natural grasses, leave the ground fallow for a year or two so the wireworms die off. Will provide updates as we get them.
Lots of Interior Growers are being inundated with Lygus bugs this summer. Several years ago USDA scientists identified two species on peonies and noted that they were most frequent on peonies near birch trees (Lygus borealis and L. punctulatus). But now they have been reported from North Pole, Chena Hot Springs, Fairbanks, and Nenana chewing on young buds. They come in a variety of colors and sizes but they all have that characteristic triangle on their backs. We have seen them at the GBG but not in great numbers, and we have yet to see any damage from them. Right now the buds here are oozing their sweet sappy nectar, and that might be an attractant. So far the CES folks have identified only one locally available spray- Orthene 97. Ron & Marge sprayed their fields, and it appears like it might be working. Too early to tell, though. Photo courtesy of cedarcreek.umn.edu
I was in Anchorage over the weekend, and I stopped by the Alaska Garden and Pet (Mill and Feed). They had a snazzy poster advertising Arctic Grow Peony Blend with minors. I talked to the woman behind the counter, and she told me the recommend rate is 1/2 cup fertilizer per plant. That is so impressively huge, I would like to find out where that recommendation came from. I contacted the soils people here, and Bob VanVeldhuizen did a little math. He took some pictures of what that level of fertilizer would look like, and he also made a rough guesstimate of how many pounds per acre that amounts to. For most of our garden we use about 500 lb per acre 10-20-20 as a general application once a year. Bob’s illustration shows about half that- -a recommendation for grains. If you apply 1/2 cup per plant around about a 6 inch diameter hole for a peony root, he estimates that recommendation will amount to almost 18,000 lb per acre! Not only is that way too much fertilizer, those roots haven’t even established their fine feeder roots, so most of the solubles will be lost to leaching into the soil. I saw a whitish ring of fertilizer on top of the soils in some peony fields last summer and a lot of shoot death.
I have very fertile soils, and for the first five years, the peonies at the GBG got NO extra fertilizer except what was in the ground. I am certainly not advocating that route, but the 1/2 cup per plant can burn fine feeder roots, cause such high salt levels in the soils as to kill those big storage roots, waste money, and cause problems with groundwater. This fertilizer also has micronutrients, but I couldn’t figure out how much. Micronutrients at high levels can cause toxicities that can last for many, many years. I usually apply approx. one tablespoon of 10-20-20 per plant to mature plants. On new soils that would be higher, but 1/2 cup? Not!
Here’s a link to a 1907 manual about growing peonies. Not all the information is accurate, but it is a fun read for people who like history. It is available as a free download via archives.org
“Yes, when the love of the beautiful is dead in the souls of the people, when billions on billions have been raised to fill all the empires of the west and northwest. The love of the beautiful is growing, not dying, and when you get to raising the most charming, as well as the hardiest, flower on earth, you may be absolutely sure of success. If you want to be gone a week, your plants will not be like chickens, dying for lack of care. All the long, cold months of winter they are independent of you. There is no enterprise which will give you such congenial employment, which will so compound interest for you on such a bountiful scale and bring in such returns for the capital invested. Be sure and begin right. Get the best kinds [of peonies] and give them good care and your reward is certain.” C.S. Harrison