Mid-Winter Checklist

Paul Pilon

He’s making a list, he’s checking it twice. No, I’m not talking about St. Nicholas, I’m referring to a grower’s practices midway through the overwintering period. Just because the perennials are all nestled in their beds for a long winter’s nap, doesn’t mean it’s all sugar plums dancin’ and all is well. On the contrary, there’s plenty to think about, and as you know, things could go astray this time of year.

I find wintertime is a great time for reflection and to review the past, look at the present and plan for the future. Although each grower will have their own lists unique to their operations, here are some items I think could be on most growers’ past, present and future lists.


Crop timing—Which crops weren’t marketable when they were expected to be? Perhaps they were too small or not flowering. What was the reason? In many cases, growers use the wrong starting materials. Each year, I come across spring-planted blocks that never flowered as the result of growers using starting materials that haven’t been vernalized. Using the wrong production schedule or growing the plants in the wrong environment are other reasons plants aren’t ready on time.

Cultural problems—What cultural issues did you face during the previous growing season? In many cases, these issues will reoccur from year to year. Should you implement a preventative program? If you had one in place and still experienced the issue, did you use the right products, apply at the right frequency and achieve the right coverage? Although, monitoring the crops doesn’t prevent problems from occurring, it allows you to detect and manage any issues before they get out of hand.

Other—I’ve provided a couple of areas to reflect on, but there are numerous others. Be sure to self-reflect on areas such as purchasing, inventory management, labor, logistics, marketing and other segments that have great effects on your business and its bottom line.


Moisture—Keep in mind that although plants usually don’t use much, if any, water during dormancy, water plays an important role with protecting the crowns and root systems from injury from freezing temperatures. You don’t want to keep them saturated, but maintain the containers just under container capacity to provide the most protection from cold. This is particularly important around the outside rows where the temperatures are usually the coldest. The plants also are usually dryer around the perimeters as well. Level 3 is a good place to be.

Cold protection—I generally recommend growers wait as long as possible before placing protective blankets on top of their perennials. I like to allow the plants as much time and exposure to freezing temperatures as possible to allow them the best chance of getting acclimated to cold. Protective coverings aren’t usually necessary at the onset of dormancy and cold temperatures; rather they’re intended to provide cold protection during the coldest periods of the winter. Protective blankets are very important during the late winter and early spring as the plants begin to de-acclimate and are particularly susceptible to freeze events. Blankets should be actively managed throughout the winter instead of being placed on crops and forgotten.

Pests & diseases—Crops should be checked on a regular basis to detect any unexpected issues. Rodent damage is very probable; check for damage and monitor the bait stations at least every couple of weeks. With cold temperatures, diseases and insects aren’t usually problematic, however, they can appear in the late winter as the days become longer and warmer. Botrytis can be active at low temperatures and often attacks evergreen perennials in late winter. Increase ventilation and reduce temperature fluctuations in locations with susceptible crops. Preventative fungicide sprays may also be beneficial in late winter.


Lastly, I like to use the winter to get prepared for the upcoming growing season. One preparation I like to do is to develop crop protocols or production plans for crops I’ve had past challenges with or for new perennials I’ve never grown before. Wintertime is when I review past results and develop future strategies. One example would be developing a PGR plan; if I was happy with the results I’ve obtained in the past for each particular perennial, I’d stick with what's worked. However, if the results weren’t satisfactory I’d develop a new height-management strategy. In the winter, I develop any preventative programs for controlling pests and diseases and guidelines for when to begin implementing them.

I also use the winter to review the sales plan for the upcoming season and to verify each crop is in the right location to meet the intended sales dates. This allows me to structure a heating plan and identify which crops are in the wrong places. Doing this in advance reduces heating crops that don’t need to be heated and eliminates panic moving later on. GT

Paul Pilon is a Perennial Production Consultant and editor-at-large of the Perennial Pulse e-newsletter. Feel free to contact him with article topics or to address your perennial production challenges. He can be reached at