Epimediums can be drastically affected by fickle spring temperatures because they are such early bloomers, emerging as soon as the frost is out of the ground. Unseasonably early spring warmth pushes the new growth into overdrive, and then sudden, hard frosts can fry it all up into a pile of withered stems. Most years it is not much of a problem, but then there are years like the present.
Lately we have been riding a roller coaster of temperature changes in the Northeast, with warmth coming many, many weeks earlier than normal, pushing these early bloomers into premature growth. Now, in early April, we’ve had 4 days of lows in the mid-teens. Luckily we’ve also had recent snowfall, which provided nearly 6-8″ of protection, hallelujah! I think I was the only person I’ve encountered who was grateful rather than annoyed about it.
I have tried to lessen any damage to the plants I have in pots by ignoring the temptation to uncover my cold frames early (much to the chagrin of my southern customers). Normally I open them up in mid-April since our frost free date doesn’t arrive til the end of May. In observing my Epimediums yesterday after the snow had melted under rising temperatures and warm rain, I found that some had weathered the trauma better than others, but most looked unscathed. Here’s my secret:
I keep my plants as dormant as I can, for as long as I can, until the weather settles in spring.
When I cut back the old foliage in either fall or early spring, I mulch the roots with 2″ of chopped leaves (or any other lightweight mulch appropriate for perennials), and sprinkle a lighter covering of this ‘leaf confetti’ over the crowns of each plant. This keeps the soil cool/frozen until the weather moderates. Even covering them in early winter with the branches of your discarded holiday tree will give added protection.
Another trick to slow their eager, early emergence is to plant them where the spring sun does not reach, such as on the north side of the woods, a shrub border, or your house. I have my entire stock of overwintering pots in cold frames located on the north side of a woodland, whose shade serves to keep the plants dormant for longer than they would remain that way in a more open location.
A third method is to plant under the cover of a limbed-up evergreen tree or shrub that will give them a bit of overhead cover that moderates the temperature. My favorite way though, is my excuse for being a lazy gardener (in all fairness, I am not lazy, I just have LOTS of garden/nursery to cut back each year before the new shoots emerge).
Leave last year’s foliage along with the fallen leaf debris to moderate the effect that quickly changing spring temperatures have on the new buds. Leave it in place until the weather settles or you have a chance to clean it up and re-mulch the area in readiness for bloom. If you use this technique, keep a sharp eye on the weather — thank goodness for the advent of the 10 day forecast–how could I live without it?! Do not postpone cleanup for too long however, or you will have the impossibly tedious task of removing the tangle of old stems and dried foliage from the tender, brittle new shoots. If that happens, it may be best to let things be and have the two fight it out. You will end up with taller plants in any case. As you can probably guess, I have long since given up what the neighbors think about my garden in earliest spring.
If all else fails and you have the threat of a late, hard frost looming, an old cardboard box and a rock to weight it down works in a pinch– at least for your most prized specimens.
Even if your Epimediums do get freezer burn, all is not lost. The underground woody rhizomes of most will activate dormant buds that will continue on. They will emerge a little later and with a lesser floral show, but thankfully, after the weather has settled.
If there is one thing that I have learned in life, it is that Mother Nature is a power greater than myself, and it is best not to stress, but to roll with the punches and enjoy the ride. In other words, work smarter, not harder. If you can do that, it makes life much, much better.
With best wishes that your Epimediums have made it through spring so far unscathed. I am keeping my fingers crossed for more moderate spring temperatures from now on.