Sometime in the summer of 2009, I was made aware of a new product coming to market under the label FreezePruf™, touted to protect plants from cold damage by a margin of over 9°F. As an example: a plant that sustains cell damage starting at 32°F would, with this product, be protected down to under 23°F.
I decided to order a gallon of FreezePruf™ — enough to make 4 gallons of solution — and test it on a number of my small Lycoris plots over the winter. Little did I know our region would receive some of the coldest temperatures seen in 15 years.
Application & Methodology
On November 15th, 2009, after experiencing a few frosts and freezes down to as low as 30°F with minimal foliage damage, FreezePruf™ was applied according to directions across all upper-facing leaf surfaces, which were fully established by this time. Lower surfaces were difficult to reach, making thorough application impractical — any reported results should take this limitation into consideration.
FreezePruf™ directions recommend a six-week re-application interval during periods when damaging temperatures are anticipated, with application above 50°F and at least 12 hours before the next freeze. The initial application met these guidelines; the next was scheduled for around January 1, 2010.
Winter Weather Record
Temperature Log — November 2009 – January 2010
The scheduled re-application around January 1st was impossible: conditions were either wet or subfreezing throughout that period, preventing any second application before the historic cold of early January arrived.
Results
Photographs and evaluations were taken on January 18, 2010, across all test plots. Below are the generalized observations for the range of outcomes observed.
Worst Case
Lycoris aurea var. surgens
The most tender member of the Lycoris clan proved it needed far more than a spray protectant to survive. Foliage was completely burned back. This plot was in open ground in full sunlight.
Best Case
Lycoris ×houdyshelii
This open-ground plot in full sun received minimal damage — one of the most impressive subjects in the trial. Foliage was even more upright than other plots, and the residue of the first treatment was still visibly present on the leaves at evaluation time.
Conclusions
Acknowledging that this is only a practical, subjective study, I believe FreezePruf™ deserves further evaluation as a nursery tool. Based on the observed behavior of the Lycoris radiata group and L. ×albiflora, there appears to be significant protection from very drastic low temperatures not normally recorded for this region.
It is also important to note that a proper application to the underside of the foliage was not feasible, and the scheduled second application was not possible before the lowest temperatures were reached. An additional application was made to surviving plots on January 18th after photographs were taken.
This product will likely be evaluated again in a future season, ideally under more normal temperature conditions and with a properly timed second application.