The peonies are coming! For those of you who have learned this from us before, bear with me as I go over the proverbial question; ‘when should I remove my mulch on my new peonies’? This will be an all encompassing answer for USDA Zones 2-5 that we suggest mulching all first year peony plants. The short answer is ‘when the tulips are 6-10 inches high’. I’m not an agronomist or soil chemist or weather person, but I always look for tulips, period. Over many decades of growing peonies as a hobby and commercially, tulips have never failed me. If yours or your neighbors tulips are this height, start removing and discarding your mulch!
We also receive questions on ‘why do I have to mulch my new peonies’? Well, the only time we lost significant amount of newly planted peonies was when we did NOT mulch in our 4b zone. That was the last year we did that! Here’s my dissertation, I’m not so much concerned with winter ambient temperatures, unless they get down to -40F actual for herbaceous, -30F for intersectionals and -20F actual for Japanese tree peonies. (By the way, our Roger Anderson’s tree peony seedlings are still a few years away so will leave those out of this conversation for now.) What I am concerned with is the depth of frost in the ground.
When the ground warms up in the spring, the frost is pushed to the surface as the lower levels begin to warm. In a year with less frost depth, no problem, but here and other lower zones, frost can be 4 feet or more especially if there is not adequate snow depths. Because the bare-root peonies were planted in their dormancy phase, they have not developed their root structure to hold them in place. As the frost layer is pushed higher quickly with the warming sunlight, we need to allow the ground to warm up slower. Thus mulching is the key to allow the ground to warm up slower and prevent the roots from heaving. So back to our tulips, they are truly the sign to let us mere peony gardeners know when mulch removal is appropriate.
So this is the earliest we have ever removed mulch and I’m sure we may see colder temps before the peony soldiers start growing their stems. So what happens if below 32F degree temps return? For us anyways, it is what it is and the good Lord has watched over peonies longer than any of us have. I’m not too concerned unless day AND nighttime temps are below 19F degrees for 3-days in a row. Again, the frost is out of the ground and if the ground refreezes, will it go down inches or feet? My guess is inches. If this spring does turn out to be the wackiest ever, I will post updates to these what if’s as the days of spring 2016 continue. In the mean time if you have removed your mulch and take into account my prior sentence on temps, I would leave the peonies alone.
For those of you in USDA Zones 6-8a, see how easy it is to grow your peonies? Would we ever move to a higher zone? Absolutely not! We love change…I think! You enjoy your zones no matter what happens as we look forward to the 2016 peony growing season!
Take Redd’s advice, remove your peony mulch like he instructed us to do!
The first sign of herbaceous peony soldiers appearing!
Ok don’t forget about us Japanese tree peonies! We too like to show off our peony soldier buds!