Now that July has arrived, most of us throughout the Northern Hemisphere have finished picking peonies. While there are exceptions (AK), the majority of flower growers are past the peony bloom season and shifting their focus to other crops. Now however, is not the time to neglect peonies!

In fact, this period of time is the single most important season for peony roots. After flowering, the peony plants shift their focus to root growth and the formation of eyes. What happens during the time directly following flowering, is what determines the quantity and quality of blooms for the next season.

After blooming, the peony fields should be thoroughly cleaned. This means physically removing all dead or discarded foliage, cutting off flowers that were not harvested, and taking time to remove any diseased or fungus effected growth from all areas around the peonies. Black or brown foliage, leaves with spots or yellowing, and any stray organic material must all be removed. With warm summer rains come fungal attacks, and the best way to protect the peonies is to be proactive, removing any potential vectors, and keeping plantings exceptionally clean.

This is also the time to spray the peonies again. A summer application of fungicide and fertilizer will reap great rewards moving forward. Fertilizer should be with a low “N” number, and a higher “P” number. On our Vermont farm we use a liquid fertilizer mixed with seaweed extract. The seaweed has been proven to reduce plant stress, and summer heat waves cause plenty of that! As for fungicide there are many options, but most important is that the product is targeting botrytis. Great results can be achieved with biological fungal controls that actively feed on fungus spores. When spraying a biological fungicide, we are essentially coating the plants surface with an inoculation of bacteria that will “come alive” and feed off of fungus spores to survive. Two sprayings, 3 weeks apart, that include both fertilizer and fungicide will help peony plants set the stage to thrive the following season.

Irrigation is also critical during this time, although often overlooked! Even though the plants are not blooming, we still need to provide them with the equivalent of 1” of rain per week. Dry roots will not be able to send out extensive new growth, and subsequently the roots will not set many eyes for the following year’s flowers. It is much preferable to deliver this water via drip irrigation, since overhead watering can increase disease and plant stress.

Take these steps now, and reap the rewards next peony season! 

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Best Wishes,

Walt

About the Author: Walt Krukowski started Mountain Flower Farm in 1998, and has been growing peonies on a hillside farm in Warren, VT ever since. Mountain Flower Farm specializes in shipping seasonal cut flowers and woody branches to discerning floral designers nationwide. The farm also produces peony root divisions and provides them at wholesale prices to growers throughout the USA. You can visit online:  www.mountainflowerfarm.com