Spring has fully come and now we’re marching on towards summer. The majority of plants have budded out and we are able to see what the year is shaping into. As a follow-up to our previous blog on the effects of this winter, I wanted to give a damage report of the plants that were the hardest hit. In most cases these plants struggled not from the warmer weather but from the lack of moisture.
We did have some subzero temperatures at the very beginning of winter in November/ December, which were followed by record high average temperatures and little to no snow cover. Just because the plants are dormant does not mean they are not still respiring (breathing). A plant needs several ingredients to be able to successfully breathe. One of these is water. This means that a lack of significant precipitation during the winter can lead to dehydration, dieback and sometimes death of a plant. To give an idea of how far behind we were: as of the beginning of May we were about 2.5 inches below the average for precipitation. A growing season that starts with that heavy of a handicap is going to show signs of the setback.
The following list of plants show their name and the general damage pattern that we have seen this year:
Euonymus fortunei(Wintercreeper)- being somewhat evergreen, these plants have winterkilled down fairly low and will need to have the dead foliage trimmed off.
Spirea japonica(Japanese spirea)-specific varieties include Anthony Water and Gold Flame. These were one of the harder hit plants and many have died back to ground level or in some cases completely. The tricky thing about this plant is figuring out if it is actually dead through the root system or just to ground level. It would be best to cut out any dead and be patient to see if these will come back.
Flowering plums– one of our employees lost their flowering plum this winter as well as several other sad tree owners. The good news is this does not appear to be so much species specific as it was a result of previously weak trees being unable to make it where the stronger trees had no trouble.
Caryopteris(a flowering perennial)– this perennial did not do well overall and is showing many cases of having simply died back completely.
Potentilla(multiple varieties)– a flowering shrub that is also in the list of plants that have died back severely.
Green Ash– Young and even mature specimens of this tree have shown up with large limbs that have died back to the trunk. We recommend trimming out the dead and checking the root structure to make sure there are no other signs of weaknesses around the root flare.
Norway Maple– This was one that took us by surprise. We have found multiple cases of full canopied, beautiful Norways completely dead this spring. As with the Green Ash we recommend checking out the root structure to look for other signs of weakness in the root system on these trees.
Shrub roses– many of these will look dead but they have died back only to ground level and will need heavy deadwood pruning to get them to revive. This is not universally true as those in unprotected areas have died back through the root system as well.
Prunus fruit tree varieties(esp. Peaches & Apricots)– these will very likely show damage via sunscald along with other younger/ thinner barked trees.
Weeping flowering cherry– many of these are considered borderline for the southeast Idaho temperature zoning and are showing up with severe dieback or death.
There were many other plants that had the potential to be more affected but the record rainfalls that came down in last August and September got plants well hydrated prior to winters start. Any plant has numerous factors that contribute to its overall health so when a plant dies during a stressful winter (for a plant) it is only the straw that finally broke the camel’s back. It is best to use a winter like this to look for the weak spots in your PHC(Plant Healthcare) program so as to better be able to avoid loss in the future. If living in Idaho has taught us anything, it is that no winter is going to be exactly the same as the past!
If you are not sure if your plants made it and would like one of our arborists to come and see please feel free to call our office at 208-523-5296!