Denny Schrock

frosted

It isn’t pretty. Three successive nights of freezing temperatures in my yard have taken their toll on a landscape far advanced beyond its normal stage of growth for this time of year due to an unseasonably warm March. At first glance things don’t look too bad. The creeping phloxes are still blooming their hearts out; the Bloomerang lilac sports its fragrant blossoms next to the deck; and the overall effect is one of a lush, green landscape. But look a little closer, and you can see the damage.

I expected some injury to plants. With several thousand different perennials, trees and shrubs in my half-acre yard, I simply couldn’t protect them all. With the exception of tender annuals and tropicals that I covered with floating row covers, moved into the garage or crowded onto the front porch and deck, everything else had to fend for itself through the freezing weather. I’m unsure of the exact low temperatures the past three nights. However, a nearby weather station reported 28 degrees F the first night, and it was supposedly a few degrees colder the second night. This morning the yard was covered in white once again.

This is what 'Jane' magnolia looked like a couple of weeks ago.

Some of the plants showing frost damage were predictable. Saucer magnolias often get nipped by late frosts here in the Midwest. True to form, ‘Jane’ magnolia was injured in this freeze cycle. But because she was already done blooming, it was her leaves that turned brown and limp rather than her gorgeous pink blooms. Leaves of butterfly bushes and caryopteris often curl with the first frost of fall; they did so this spring too.

Other injured plants were more surprising. Chrysanthemums withstand fall frosts with ease, blooming through early autumn cold snaps. But their tender new shoots in spring are quite sensitive to the cold. In some instances, damage may be due to microclimates in the yard. My ‘Miss Canada’ Preston lilac was totally trashed (see photo below), while all other lilacs escaped unscathed. Of the dozen or so daylilies in the yard only one showed injury. ‘Strawberry Candy’ developed bleached leaves where frost settled on top of the plant.

This pink flowering deutzia was fully budded with bright green foliage just three days ago.

I'm sure that this 'Miss Canada' lilac won't be blooming this year!

Although the leaves are still green, this ginkgo foliage looks more like wilted lettuce after the freeze.

Kamtschatka sedum shows the effects of microclimate. The green side of the plant was next to some ornamental grass which protected it.

Although the shepherd's crook on these peonies looks bad, they fully recovered, and now are standing fully upright.

I conducted an inventory of damaged plants, dividing them into “severely damaged” and “lightly damaged” categories. Severely damaged plants showed extensive wilting, browning and/or dieback. Lightly damaged plants included those that had a few wilted shoots, nipped leaf tips or slight discoloration. Of course, these are somewhat arbitrary divisions, but I’m including the lists here for you to compare damage in your yard or to help you know which plants are most sensitive, and need protection the next time freezes arrive.

Severely Damaged:
‘Jane’ magnolia – sweetbay magnolia was OK
Blue mist spirea (Caryopteris) – all varieties in the yard
Deutzia – ‘Chardonnay Pearls’ and ‘Pink’, virtually all foliage blackened
‘Miss Canada’ Preston lilac (Syringa) – all other lilacs undamaged
Ginkgo (Ginkgo biloba)
Butterfly bush (Buddleja) – all varieties
Endless Summer hydrangea – other mopheads also affected; paniculata types except Little Lime unaffected
Astilbe – all varieties
Hardy kiwi (Actinidia)
Chrysanthemum – half a dozen varieties burned back
Kamtschatka sedum (Sedum kamtschaticum) – a dozen other sedum species and varieties mostly unaffected
Japanese anemone – all leaves blackened
Rose of Sharon (Hibiscus syriacus)
Strawberry – open blossoms blackened; foliage unscathed
Purple flamegrass (Miscanthus purpurascens) – almost all new shoots browned
Russian sage (Perovskia) – all shoots wilted and drooping

Lightly Damaged:
Lemon balm – a few brown leaves
St. Johnswort (Hypericum) – shrubby kinds OK; herbaceous types show some wilting
Jupiter’s beard (Centranthus) – a few damaged leaves
Boxwood (Buxus) – only one variety out of four had wilted stem tips
Weigela – only one variety affected the fist night; several more damaged the second night
Mukdenia – outer leaves browned
Lungwort (Pulmonaria) – some damaged leaves
Calamint (Calamintha) – half of shoots affected
Crape myrtle (Lagerstroemia) – only a few new shoots damaged
Lily (Lilium) – one or two varieties of the dozen in the yard showed watersoaked leaves
Rose (Rosa) – Pink Double Knock Out and Deja Blue had wilted new shoots; more than a dozen other types OK
‘Purple Pygmy’ agastache – half a dozen other agastaches had no damage
Itoh peony – a few bronzed and wilted leaves
Beautyberry (Callicarpa) – a few new shoot nipped
Japanese painted fern (Athyrium) – some browned leaves
‘Sarastro’ campanula – half a dozen other campanulas were fine; this one was wilted
Dwarf goatsbeard (Aruncus) – browned foliage
Japanese toad lily (Tricyrtis) – watersoaked foliage
Leadwort (Ceratostigma) – some browned foliage
Lavender (Lavandula) – one variety with wilted tips; half a dozen others OK
‘Rozanne’ geranium – a few wilted stems
‘Strawberry Candy’ daylily (Hemerocallis) – bleached foliage
Winterberry holly (Ilex) – new growth browned; also some damage to blue holly
Chinese cabbage – some bleached leaves; they had been transplanted outdoors just a week earlier

 

2 Responses to “ frosted ”

  1. I was wondering why the base leaves of my clematis were limp and brown, even though I had covered it during the frost, evidently the base didn’t get protection…I was thinking it was over watered since the leaves were limp, but not all were, so I was confused!

  2. Sandee,
    It sounds as though that’s what happened to your clematis. Any tender foliage sticking out from under protection could have been damaged. As long as the stem itself wasn’t frozen, the protected leaves should continue to grow and blooms should form as they normally would.