Posted by: HortAlaska | May 16, 2018

Vase Life of Peonies – add sugar or not?

The dynamics of starch and sugar utilisation in cut peony (Paeonia lactiflora Pall.) stems during storage and vase life E.F. Waltona,∗, H.L. Boldinghb, G.F. McLarenc, M.H. Williamsa,1, R. Jackman 2010. Post Harvest Biology and Technology 58:142 – 146. Peony carbs vase life.

This article published in 2010 from NZ scientists examines the quantities of carbohydrates in fresh cut peony stems stored up to 8 weeks at 0C and compared them with flowers still attached to the plant. The idea was to determine if there was sufficient carbs in the cut stems to promote max. vase life or should they try to increase carb production in the field or add carbs to the vase water  to extend vase life

They used ‘Sarah Bernhardt’ peonies. Fresh cut stems that had not been stored (control) opened in about 4.9 days and remained at the full bloom stage for an additional 9.1 days. Field flowers had a similar vase life. Flower buds stored 8 weeks opened much more rapidly in 1.9 days and remained at the full bloom stage for 7.1 days. At the beginning of vase life trials, non structural carbs made up 27% of bud dry weight and during flower opening, carb concentrations declined to only trace amounts. The biggest decrease occurs just as the petals begin to unfurl. At the same time total sugars increased and peaked when flowers had fully opened, then gradually decreased as the flower senesced. The main sugars were fructose and glucose.

Flowers still in the field showed that the amount of sugar moving into a stem  during flower opening was about 3.2 g or about 14.3% of dry weight of the whole stem or 42% of the dry weight of the open flower. It would follow, then, that adding sugars to the vase water of fresh cut stems might extend vase life by improving carbohydrate levels in the flowers and stems. However, when comparing the flowering sequence between flowers in the field and fresh cut flowers, there is no difference in the number of days flowers take to open or in the total vase life. The authors conclude that even though there is a big influx of carbs into the stem and flower, carbs are not a limiting factor in vase life.

They propose, instead, that the big difference is in what happens to the starches. In  cold storage, starches are hydrolyzed (broken down into simpler sugars)  in the tissues within the first two weeks, something that does not occur in field or fresh cut flowers. This resulting massive availability of sugars leads to very rapid flower opening in stored flowers and shorter vase life. So how do you slow starch hydrolysis in storage?

 

 

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Posted by: HortAlaska | January 20, 2018

Flower Bud Initiation in Herbaceous Peonies

The following paper is an exhaustive anatomical look at flower bud initiation in herbaceous peony identified as Chinese Peony. Flower buds of cultivar, ‘Dafugui’ were sampled exhaustively, fixed in an alcohol solution (FAA), then embedded in paraffin. The blocks of paraffin were then sliced into very thin sections, stained with different cellular dyes, and examined beneath the microscope. This process, by itself, deserves applause for the sheer patience it requires of the authors because the photos you see do not just happen by chance. The researchers have to sample hundreds of buds and examine thousands of thin sections before they find the exact stages of flower bud development they seek. I know a bit about this because I conducted a similar study of flower buds of lingonberry, Vaccinium vitis-idaea, for my PhD thesis years ago. It tested every iota of my patience—seeking the very early stages of flower bud initiation that are not visible with the naked eye. In regards to lingonberry, the vegetative buds showed the transition to flower buds way back in June (Fairbanks, AK) long before you could actually tell there was a flower bud present.

There are other methods of discovering this transition from vegetative buds to flower buds, but they all require harvesting a lot of buds and guessing when the flowering structures will show up. For most flowers, lingonberries and peonies included, the vegetative bud starts out as a dome shape similar to the eraser on a pencil. A trigger or triggers– could be photoperiod, age of the plant, nutrition, genetics, temperature, etc.- induces that dome to flatten out into a series of rings that give rise to a ring of sepals, another inner ring (or more) of petals,  then a ring(s) of stamens and finally the pistils. From the side (longitudinal section), they look like bumps.  In peonies, it is even more interesting because a lot of the stamens sometimes transition into petals, thus forming petaloid stamens.

The timing of these events is interesting both from the botanical standpoint of which factors might be triggering the development of flower buds but also the environmental factors that might be involved in interfering with this transition. For instance, freezing weather in autumn might stop the process of flower bud initiation and development. Maybe poor root growth and lack of nutrients prevents the transition from happening or it happens partway so the flower bud aborts.

In these Chinese flowers growing at the Heilongjiang Forest Botanical Garden, flower bud initiation begins in early September. The sequence is like this:

Early September – Flower bud initiation

Early to late September –Flower bud bract differentiation

Late September to mid October – Sepal formation

Mid October – late Nov – petal formation

Mid November – Early March – male stamen formation

April – female pistil formation

Pollen development, maturation of the anthers occurs in late winter and the female ovules develops during early spring for flowering that occurs in early to mid May.

Think about all the environmental factors that could impact this developing flower bud from September through flowering in spring. It is mind boggling to think of all the weather factors, insect pests, diseases that could interfere with flowering.

In Alaska, we have no idea when flower bud initiation begins, and the whole process would have to stop in late autumn when the ground and buds freeze. All of this development would resume some time in spring and is, no doubt, one reason why Alaska flowers bloom so much later than lower latitudes. We know that peony flower bud initiation is not mediated by photoperiod, but what are the triggers that initiate that transition from vegetative to flower buds? Anyone for a PhD?

Peng, M. FL Huang, FJ Meng, BZ Hu, XF Chen, R Luo, N Li, RF Wang, Y Zhao, QW Zou, CT Wu and JL Dai. 2017. Reproductive Biology of the Chinese herbaceous perennial peony (Paeonia lactiflora Pall.) using the paraffin method. Φyton International Journal of Experimental Botany. 86:296-305.   Peony flower bud initiation

Posted by: HortAlaska | December 24, 2017

Peonies for Your Garden – A Good Read!

CCI24122017_3CCI24122017Julia roseOne of my Christmas presents to myself this season is a copy of the newly released book, Peonies The Best Varieties for Your Garden, by David Michener and Carol Adelman. David is associate curator of the U. Michigan Matthaei Botanical Garden which houses one of the largest collections of peonies in the nation. If you ever get to Ann Arbor at peony blooming time, it is a spectacular collection, one that holds a lot of heirloom varieties that are being verified using DNA fingerprinting.
 
Carol Adelman needs no introduction to many Alaska peony growers since she and her husband were guest speakers at Alaska Peony Growers Association events. She has also generously hosted tours of her business Adelman Peonies, better known as Peony Paradise. If you ever have a chance to go to an American Peony Society annual meeting or the Pacific Northwest Regional meetings, Carol will demonstrate why she is considered one of the nations foremost authorities on peonies.
 
I ordered my copy right away from Adelman’s Peonies (peony paradise.com) because I knew with Carol as an author, the book would be stuffed with accurate information about the nearly 200 varieties listed, and the photos would be fabulous! It includes most of the standard varieties grown in Alaska a cut flowers. One of my favorites is the photo of ‘Duchess de Nemours’ which shows a giant white puffball – often listed as the standard pure white peony. In Alaska, this cultivar starts out white, but the Interior, it gradually becomes a blush pink, and that pink darkens over the years!
 
Publisher, Timber Press, produced a gem. The photos are true gifts for the eye, and the descriptions provide information on history, breeder, color, flower form, fragrance, garden culture and much more. Most of the favorite garden varieties are the herbaceous types, but there are gorgeous intersectional hybrids that are hardy in the warmer sites in Alaska (with snow cover in some locations). It also includes tree peonies that I cannot grow in Fairbanks but might do well in southeast AK.
 
The appendices list sources of cut flowers including 3 wholesalers from Alaska, a giant list of public gardens with peonies in the US, Canada and UK including ABG in Anchorage and the Georgeson in Fairbanks.
 
If you get money for Christmas, this book should be on your “must read” list!
Posted by: HortAlaska | November 22, 2017

Irrigation and Peonies

Kopp, K/, R. Kjelgren, P., Urzagaste and X. Dai. 2017. Physiological and quality responses of turf grass and ornamental plants to weather-based irrigation control. International Turfgrass Society Research Journal. 13:537-546.

This article published out of Utah State and U of Florida was an interesting article testing weather-based irrigation controllers and plant growth. The researchers used three unrelated plants that have very different rooting habits: Kentucky bluegrass (Poa pretenses), an ornamental Euonymus (Euonymus alatus ‘Compactus’, and herbaceous peony, (Paeonia lactiflora). The purpose of the project was to learn if there was any water savings with the use of irrigation controllers that are programmed to take cues from Mother Nature on when to irrigate and how much. The experiment took place in North Logan, Utah where water certainly is at a premium. By using controllers that are programmed to fit the local weather patterns such as sunshine, rainfall events, evaporation rates, etc.  with plant water demand, they hope to make the entire use of irrigation water more efficient.

The weather controllers they compared were Hunter PC-300 controller with Solar Sync Sensor; Rainbird ESP-LX controller with Evapotranspiration Manager and Weathermatic SL-1600 controller.

The two year study did not provide quick answers for irrigation control in peonies. Plants suffered significant water stress under the regime programmed into the controllers. Although it is a great idea, this is more a cautionary tale. Water use in plants is very complex, and obviously the researchers need to do more studies to find the right combination of weather factors that might be used to predict water uptake in peonies. For now, growers cannot rely on pre-programmed irrigation systems to determine irrigation needs. For peony growers it’s back to the old eyeball test. Plant leaves do not show a color difference with lack of water. They droop every so slightly in midday. Severe water shortage is shown by significant leaf edge curling (upward) along the long axis. Stem length is also stunted by as much as 20-30 cm over the season. The first 5 years I grew peonies in Fairbanks, I did not irrigate and saw no symptoms of moisture stress. That does not mean irrigation was not necessary. They might have grown better with irrigation, but stress to the point of degradation did not occur. After 5 years, however, plants that had become established with very large root systems showed water stress every season beginning in mid June about 2 weeks before flowering.

 

Posted by: HortAlaska | October 28, 2017

New Botrytis species for Alaska

   When Dr. Gary Chastagner and grad student Andrea Garfinkel started their work with peonies in Alaska and Washington state, none of us were prepared for the great diversity shown by the Botrytis disease. Although most of the collections were identified as B. cinerea and B. paeoniae, many more interesting species (up to 10, perhaps), some identified, and some still being studied, emerged. I think the oddest one of all is a new species, B. euroamericana, that was identified by the WSU folks and was also identified on, of all things, grapes! Researchers in Verona, Italy identified the same species several years ago. Why in the world, this species showed up in such disparate species located on different sides of the globe is a mystery! Now Alaskans can claim yet another association with Italy! The Gold Rush in the Fairbanks area was started by the discovery of gold by Felice Pedroni (Felix Pedro) in 1902, a native of Trignano, Fanano in the province of Modena, Italy! This is certainly one for the Alaska trivia books! Read more about this species in the following journal article:

Botrytis euroamericana a new species from peony and grape in North America and Europe

 

 

Posted by: HortAlaska | September 14, 2017

Weed control with abrasives

Abrasive Weeding: A New Tool for Weed Management in Organic Agriculture

Organic Agriculture September 06, 2017

Frank Forcella, USDA-ARS

Sharon Clay, South Dakota State University

Daniel Humburg, South Dakota State University

The attached fact sheet is a summary of research using abrasive products such as corncobs and even fertilizers to kill weeds in organic farms. I’m sure it is like sandblasting except the abrasive is not sand. The method is not 100% effective, but the scientists did achieve a fair amount of control to warrant its use. They were working with a variety of crops from corn to raspberries as well as tender seedling transplants of crops like tomatoes, broccoli and peppers. Two applications yielded 50-95% control of weeds around plants. Young annual weed seedlings can be killed outright, but perennials are tougher. It might be interesting to try in peony fields. I would bet that on newly established fields, you might be able to get pretty good control, but if fields have been choked with weeds for a couple of years, it might not be successful.

Abrasives as weed control

Posted by: HortAlaska | September 3, 2017

Thaw degree-days in Fairbanks

For a garden club presentation I gave this past spring, I graphed the weather records from the Fairbanks Experiment Farm to look at changes over time. The biggest one goes back to 1948 and is for thaw degree days. This chart is a broad indicator of the warmth of the season. Average daily air temperature records are subtracted from a baseline temp of 32F. This assumes that plant growth occurs at any temp above 32F but not below. This is not quite accurate because cell sap does not freeze at exactly 32F, and there are Alaska native plants that can grow at temps that are a few degrees below 32F. On the other end of the spectrum, garden plants have all kinds of lower limits to growth- cool season crops are often around 40 – 45F below which growth stops. Warm season crops are more like 50F and above. However, choosing 32F at least allows a comparison of the seasons. The thaw degree- day (TDD) chart is split into three just to fit it onto a page. Check out the differences among years and the mean TDD on each chart. The timeline is waaaay too short to make conclusions on climate change, but it is interesting to see the incredible variation from year to year.

1948 – 2016 Thaw degree days

Posted by: HortAlaska | August 29, 2017

Edible Peony Flowers

This article is an interesting survey of soluble sugars, organic acids, protein, vitamin C, total phenolics, total flavonoids, and mineral elements in the petals of herbaceous peonies in China. The cultivars used are Chinese, and the study shows quite a lot of nutrients in the petals. The scientists determined the optimum harvest time was full bloom, and there was considerable difference among cultivars. Interestingly, the flower color was not a good predictor of the best cultivars. In other words, all pink peonies were not the highest in nutrient values. Several growers have been making a very good, aromatic peony petal jelly, and others add petals to tea. It would be interesting to see how many of these nutrients actually survived the cooking/steeping  process.

Emirates Journal of Food and Agriculture. 2017. 29(7): 518-531
Nutritional evaluation of herbaceous peony (Paeonia lactiflora Pall.) petals
Weixing Li, Shunbo Yang, Hui Cui, Yanmin Hua, Jun Tao, Chunhua Zhou
College of Horticulture and Plant Protection, Yangzhou University, Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou
225009, China,
Joint International Research Laboratory of Agriculture & Agri-Product Safety, Yangzhou University, Yangzhou, 225009, China,
XiZang Agriculture and Animal Husbandry College, Linzhi, 860000, China
Herbaceous peony (Paeonia lactifloraPall.) is a kind of plant with ornamental, edible and medicinal values, and few studies were concernedto edible aspect of herbaceous peony petals. The aim of this research is to establish edible quality evaluation system of herbaceous peonyflowers. Petals of 46P. lactifloracultivars at full bloom period were used to determine the content of soluble sugar, organic acid, protein,Vc (Vitamin C), total phenolics, total flavonoids, mineral elements and SOD (superoxide dismutase) activity and screen out evaluation index for edible herbaceous peony. The results showed that flower petals of herbaceous peony contained lots of nutrients and the contents
varied with different cultivars. The soluble sugar content was 66.55-177.28 mg/g FW, organic acid 2.19-6.90 mg/g FW, soluble protein 6.53-121.56 mg/g FW, Vc 9.77-30.24 mg/100 g FW, total phenolics 9.41-33.01 mg/g DW, total flavonoids 3.50-17.56
mg/g DW, SOD activity 305.62-520.42 U/g FW, total amino acids 6.43-11.99 g/100 g DW. The average content of Na, Mg, K, Ca, Mn, Fe, Ni, Zn, Mo, Cr were 55.88±14.90 μg/g DW, 1218.22±349.60 μg/g DW, 11252.23±2477.54 μg/g DW, 1975.40±706.58 μg/g DW, 8.30±6.55
μg/g DW, 103.56±182.72 μg/g DW, 10.73±37.94 μg/g DW, 22.80±16.68 μg/g DW, 1.84±5.89 μg/g DW and 17.36±44.89 μg/g DW,respectively. Based on principal component analysis and cluster analysis, we found ‘Dielian Qihua’, ‘Zhushapan’, ‘Xueyuan Honghua’,
‘Wulong Jisheng’, ‘Honglou’, ‘Bingshan’, ‘Hongyan Yushuang’, ‘Zituo Ronghua’, ‘Zifengyu’, ‘Fenlou Dianchun’ had better edible quality.The results will provide some information for the comprehensive utilization of herbaceous peony petals and the breeding of edible
herbaceous peony cultivars
Posted by: HortAlaska | July 26, 2017

Tobacco Rattle Virus

This publication summarizes information gathered in Alaska and other locales for the occurrence of tobacco rattle virus, an insidious disease that shows up in Alaska peony fields from roots imported from a variety of sources. No one knows if TRV affects yields of peonies, but in some years it is definitely visible on the foliage at cut stem harvest time. The most common vector is a nematode that does not occur naturally in Alaska soils, and there are hints that it might be spread by sap or clippers. However in the 20 years I have been working with peonies, I have a few plants mixed in with ones that show no symptoms. In those years, it has not spread to adjacent plants that have been pruned and clipped every year. At least the strain that occurs in Alaska does not seem to spread.

17.Garfinkel et.al. TRV

 

Posted by: HortAlaska | June 10, 2017

Vase Life Studies

I have attached a copy of a poster my students and I completed a few years ago. We have received a lot of interest in handling practices after flowers are cut. This experiment was designed to help understand best practices. The  biggest factor is cold storage. A huge challenge for growers is maintaining consistent and cold temperatures after cutting. Fluctuations even from people walking in and out of the cooler can cause moisture condensation on the flowers, Botrytis growth, and a shorter vase life.  2010. Peony Vase life poster

 

Posted by: HortAlaska | June 10, 2017

It’s nectar time!

Nectr.5x7

The nectar began to ooze from buds, even the tiny side buds, this week when the temperature soared into the 80s and 90s. The nectar oozes from the edges of the sepals not from any specialized nectary. Even though they are called extra-floral nectaries, meaning outside the flower, there are no real specialized cells you could call a nectary. The turgor pressure inside the plant gets so great, the sweet stuff bursts in tiny bubbles all around the edges of the sepals and collects in the bracts and leaves below. A menagerie of insects cannot be far behind. The nectar is very sweet but has a tinny aftertaste. Ken H, peony grower in Homer, has bee hives in his field, and the bees do a good job cleaning up the nectar (and thus helping control sooty mold on the flowers). The honey from his hives was light, sweet, nothing to brag about in the beginning. But after a few seconds, an amazing aroma/flavor bursts inside your mouth for an extraordinary treat.

Northern Agriculture

 

 

Posted by: HortAlaska | March 24, 2017

The Chain from Kenya to Netherlands

This article highlights the coordinated effort being made between Kenya flower producers and the big markets in the Netherlands. Kenai

Posted by: HortAlaska | March 24, 2017

Cold Chain Management

This site is for a company called FlowerWatch that sells a service for managing the environment after the peonies are harvested. Their service is not something Alaska growers could take advantage of, but the site shows the importance of managing the cold chain from the field to the vase. Temperature is especially critical, and growers in Alaska should have recordable temperature monitors in their pack houses and refrigerated storage that allows growers to have precise control of their storage conditions. Everything from harvest stage to the shipping containers should be standardized across the state to allow for a great Alaska brand for everyone.

FlowerWatch

Posted by: HortAlaska | February 2, 2017

Dutch Cut Flower Trade in China

The cut flower trade is huge and ever changing as demonstrated by this move by Dutch flower industry to trade directly into China.

Dutch Trade

Posted by: HortAlaska | January 30, 2017

Vase Life of Peonies

IN 2013, 14, and 16 I examined the vase life of 69 different cultivars of peonies to see which ones would last 7 days or more in a vase. There were winners and losers, and I was especially interested in which were consistent from year to year. The zero category was mostly ITOH hybrids (starred). The greatest category had 1 of 3 years at the 7 day average vase life. There were only 6 cultivars that were consistent for 3 years. Those 6 may or may not have other attributes that make them lousy cut flowers (short stems, poor yield), but at least in this category they are stars!

0-2-years

3-years

Posted by: HortAlaska | January 30, 2017

Flower Development

I recently gave a presentation to the Alaska Peony Growers Association about my feeble attempts to classify peonies into singles, doubles, semi-doubles, etc. Even the experts in the field often classify them differently, and they can even differ from the breeder! In addition, many of us have seen all kinds of weird development on peonies including plants that have singles, doubles and semi doubles on one plant. The link below is an older video but I haven’t found an updated one. Nevertheless, it provides an interesting geneticists-eye-view of how sepals, petals, stamens and pistils are formed. It is not even about peonies, but a little mustard, Arabidopsis. It’s worth watching. And while you are watching, think weird peonies!  Here’s one with all sepals!

peony-all-sepals-3Science Matters: the ABCs of flower development

Posted by: HortAlaska | January 17, 2017

Marketing tips

Marketing Tactics

Interesting article about marketing in the floriculture businesses.

Posted by: HortAlaska | January 12, 2017

Great Research Site

Every grower should be reading the surveys published by Floral Marketing Research.

Social Media Marketing

Posted by: HortAlaska | November 20, 2016

Forcing Peonies in Israel

Check out this video on peony production in containers from Israel.

Forcing Peonies

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