Northern Shade Gardening

What Leaves Look Good After the Frost

Monday, October 19, 2009 Category: Garden Design

We’ve had a couple of weeks where the temperatures didn’t go above freezing, so the leaves of many  plants have died back. However, the leaves of  some hardy perennials are still looking good, despite the frost and snow. Here are some photos of perennial foliage that can tough out some frost, and extend the gardening season in a northern garden.

Asarum europaeum leaves October

Asarum europaeum leaves October

The Asarum europaeum (European wild ginger) leaves are semi-evergreen, and keep about half of their leaves through the winter in my zone 3 garden. This little groundcover creates a great display in late fall and early spring, when other perennials have retreated.

Asarum arifolium leaves October

Asarum arifolium leaves October

Here are some new Asarum arifolium (hardy ginger) that were just planted a few weeks ago. These are rated for a warmer zone, so I’m not sure how they’ll handle the full winter temperatures, but they don’t seem to mind getting hit with freezing temperatures right after planting. The lovely shaped leaves are still green, and make a great sight. I’m impressed that they didn’t collapse, after the temperature dropped drastically, and the drying winds blew.

Cornus canadensis leaves October

Cornus canadensis leaves October

The Cornus canadensis (bunchberry) look good, and add some red fall colour too. This groundcover creates a green display  under the evergreens, despite the temperatures.

Heuchera 'Mint Frost' leaves October

Heuchera 'Mint Frost' leaves October

Heuchera (coral bells) are another perennial that keep fresh looking leaves through the frost. Some Heuchera intensify their colour in the cool temperatures, giving lovely fall shades. This normally green and silver Heuchera ‘Mint Frost’ starts to get purple, red and orange colours as the weather turns cold. They keep these leaves until spring. The red stems make a good contrast on this showy perennial too.

Heuchera 'Plum Pudding' leaves October

Heuchera 'Plum Pudding' leaves October

The Heuchera ‘PlumPudding’ started with such an intense silvery purple, and has been keeping it through the frosts. The Astilbe next to them have collapsed, so these leaves get the attention.

Campanula poscharskyana leaves October

Campanula poscharskyana leaves October

The Campanula (bellflowers) maintain their green leaves through the cold too. They keep most of their leaves through the snow, and start the garden early in spring. They also keep some flowers long after others have disappeared. The glimpses of blue in a late fall/early winter garden are very uplifting. The Campanula poscharskyana (Serbian bellflower) above still has clusters of purple flowers. You can see I haven’t been deadheading since the frost. :)

Campanula portenschlagiana leaves October

Campanula portenschlagiana leaves October

Campanula portenschalgiana (dalmatian bellflower) has a few purple flowers, as well as the fully green leaves.

Campanula carpatica leaves October

Campanula carpatica leaves October

My Campanula carpatica (carpathian bellflower) also has a few purple bells above the fresh looking green leaves. They stand out when surrounded by the fallen deciduous leaves. My C. rotundifolia (harebell), C. cochlearifolia (fairy thimble bellflower) and other dwarf Campanula have a few blue flowers along with their well preserved leaves too. These dwarf bellflowers are showing green as soon as the snow melts in spring.

Epimedium grandiflorum 'Lilafee' leaves October

Epimedium grandiflorum 'Lilafee' leaves October

The Epimedium grandiflorum ‘Lilafee’ (lilac fairy barrenwort) has lots of green leaves, and they are just slightly twisted from the long frost.

Helleborus 'Ivory Prince' leaves October

Helleborus 'Ivory Prince' leaves October

Helleborus ‘Ivory Prince’ looks exactly the same as it did in early spring. This perennial has kept these leathery textured leaves in perfect shape for many months. They’re glossy, patterned, have a lovely form, and they have been since they appeared from under the spring snow. Yes, I have checked to make sure I didn’t plant plastic ones by mistake. They’re real and growing. This plant gets the award for best looking foliage regardless of the frost.

Dianthus caryophyllus leaves October

Dianthus caryophyllus leaves October

Dianthus caryophyllus (carnation) is another perennial that keeps great looking foliage from when the snow melts in spring to after the frost. The slender bluish gray leaves rise above the fallen tree leaves. Although I planted these purely for the pink flowers and wonderful scent in summer, I’ve enjoyed the foliage longer in fall and spring.

Geranium 'Rozanne' leaves October

Geranium 'Rozanne' leaves October

The Geranium ‘Rozanne’ have unmarred leaves and a few flowers still too. The patch of Johnson’s Blue geraniums next to them have shrivelled leaves, and no flowers, so these appear very fresh in comparison. The Johnson’s Blue got a head start in spring, but the Rozanne geranium has been the strong finisher, and much longer bloomer.

Dryopteris expansa fronds October

Dryopteris expansa fronds October

Dryopteris expansa (spiny wood fern) has the most evergreen fronds of all my ferns. The spiny wood fern usually keeps a few fronds under the snow, so it is easy to spot in spring. All of my other garden ferns have shrivelled, but these are still showing perfect pinna. The Onoclea sensibilis (sensitive fern) were the first ferns to collapse, even before the frost, when it was only 4° C (40° F).”It’s too chilly. I surrender,” they gasped as they disintegrated. It makes sense that lacy ferns with so much exposed surface area are the first to desiccate when the cold comes, so I wonder how the Dryopteris can maintain their appearance.

Pulmonaria 'samourai' (lungwort) leaves October

Pulmonaria 'samourai' (lungwort) leaves October

The Pulmonaria ‘Samourai’ leaves  still have their silver colour, and intact foliage. These long silver leaves are especially showy against the piles of brown fall leaves.

When the temperatures didn’t rise above freezing for a couple of weeks, and combined with bitter winds, we got down to about -15° C (5°  F) with the windchill. I’m always surprised that some hardy perennials manage to keep their leaves under these conditions. I’ve been adding more of these perennials to the garden, since they maintain a fresh appearance through the cold. In a short growing season, the garden can look bare when the frost hits, and temperatures don’t climb above freezing. Being able to see green leaves, or fall colour, instead of withered foliage, gives me an incentive to wander the garden in the crisper temperatures. These plants also give a quick start in spring, with an early shot of green for a northern garden.

Which plants in your garden keep their leaves the longest after you get extended freezing temperatures?

13 Responses to “What Leaves Look Good After the Frost” »

  1. Helen at Toronto Gardens :
    October 19, 2009 at 9:52 am

    Here, the Geranium macrorrhyzum is semi-evergreen all winter, something that always surprises me, as are the Arabis and Helleborus. The Heucheras also tend to stand up to winter weather underneath all the snow, but they do look tattered and have a tendency to heave out of the ground.

  2. Rebecca @ In The Garden :
    October 19, 2009 at 10:14 am

    Wow Northern, You have so many cold hardy plants. Your asarum & heuchera look perfect. Amazing, aren’t they? Especially when you see how bad some others look after the snow and cold. You’re lucky to still have bellflowers, mine stopped blooming some time ago. Terrific Post. :)

  3. Anna :
    October 19, 2009 at 2:03 pm

    Still to have our first frost and fingers crossed that it does not arrive for a while. Pulmonaria ‘Samourai’ is now on my wish list :)

  4. Joanne :
    October 19, 2009 at 3:12 pm

    I am surprised there is so much green with temperatures down below freezing for the last two weeks.

  5. Northern Shade :
    October 19, 2009 at 4:57 pm

    Helen, I didn’t know that Geranium macrorrhizum was semi-evergreen, thanks. I would like to add more plants that keep their greenery as long as possible, so I will have to check these ones out. I found I had to remove a few Heuchera leaves in spring, but most of them came out of the snow with blazing colour. Our consistent snow cover all winter and the tree leaf cover might have helped. I became enamored of Helleborus last spring, when they were the first green in the spring garden.

    Rebecca, most of the ferns gave up, and of course the iris collapse early too, so I’m glad that there are some hardy perennials to keep the green flag flying. Most of my dwarf bellflowers have kept the odd flower, with the C. poscharskyana and C. rotundifolia having the most. It wouldn’t be considered a splashy show in the summer, but after the prolonged cold, even a few are very cheery.

    Anna, the Pulmonaria ‘Samourai’ really stand out in the garden. They reflect a lot of light, so they are easily seen from across the garden, or when viewed from a window. I like them a bit better than my P. ‘Majeste’, since the leaves are longer.

    Joanne, I have been adding more perennials over the last few years that keep some green, since I don’t like to see the garden disappear so quickly in fall. Without these, the garden season seems even shorter. Plus in spring, I eagerly look for the semi-evergreen leaves as the snow melts, which is usually in April here.

  6. Mary Delle :
    October 19, 2009 at 7:12 pm

    Here in the South we look for what goes dormant and what stays fresh, as we don’t have freezes. But the cool temps make a lot of things disappear or have no new growth. I love the different perspective of your garden with some staying fresh, others limp from frost.

  7. Northern Shade :
    October 19, 2009 at 8:04 pm

    Mary Delle, last year we got a milder fall, and many perennials kept their leaves until closer to December, which was unusual. This year, the susceptible ones are already gone, so I’m thankful for the tougher perennials that recklessly keep their leaves, when most sensible plants realize that the growing season is over.

  8. The Garden Ms. S :
    October 19, 2009 at 8:30 pm

    Your Helleborus ‘Ivory Prince’ is really proving itself to be a keeper with three seasons of green.

    My Vinca minor ‘Alba’, the Heuchera ‘Plum Royale’ and assorted thymes, particularly the Woolly thyme, all came through most impressively. My Adiantum pedatum hung in there for days before finally succumbing – much longer than the Athyrium Otophorum. As this is my first year with these plants it will be interesting to see how they get through the winter. I am always hopeful :)

  9. Northern Shade :
    October 19, 2009 at 11:13 pm

    The Garden Ms. S, the Helleborus has kept some fine foliage, and it is especially noticeable in spring and fall. when contrasted with other plants. Aren’t Heuchera great for maintaining their leaves? It’s interesting to hear that the thyme kept it’s leaves. I really like the look of thyme between paving stones, but don’t have any.

  10. Dave :
    October 24, 2009 at 1:54 pm

    Hi Northern Shade,

    As usual, your wonderful pictures outshine what I can see in my garden and make me wish I were less of a plant collector and more of a gardener. In any case, after reading your post this morning (I was in Winnipeg most of the last week – they got caught by the deep freeze too), I wandered around in the cold drizzle and 60 km gusts to see what bits of cheer were still on offer. As you note the Campanula and Heuchera are still looking good, including the very modest Heuchera sanguinea that I put in this last spring. The Pulmonaria saccharata ‘Roy Davidson’ looks a little limp, but still entertaining, and is densely surrounded by still green forget-me-nots and green-turing-red bunchberry. My Helleborus ‘Red Lady’ would be a tawdry escort for your Ivory Prince, but this was its first summer: maybe next year it will put on a better show.

    Only one fern is left, the semi-evergreen deer fern (Blechnum spicant), which has prospered since 2004 and usually has a few fronds still alive after the snow melts (although these died back this last nasty spring). This is a West Coast species (California to Alaska – but inland to Idaho) and supposedly only hardy to Zone 5. Could be a lucky microclimate – the nearby cowslips are still green – but I’ve lost a few hardier plants from this bed. The Hepatica nobilis still looks good – a mound of light green liver-lobed leaves. The Pink Panda (Fragaria ‘Frel’) run here and there, pleasant even without the flowers. Nepal Cinquefoil (Potentilla fulgens) still has ladders of silvery green pinnately compound leaves. The Bergenia cordifolia ‘Winterglut’ are a spectacular mix of red, green, and red-green leaves (the species bergenia, however, look ragged) and the Wintergreen (Pyrola asarifolia) are living up to their name.

    The Garden Ms. S mentions her thymes are doing well and to me one surprise of this morning’s ramble was how may herbs are looking more than presentable. The only thyme I’ve ever had any success overwintering, Thymus x citrodorus ‘Aureus’, is almost always attractive. More or less evergreen, usually more red than golden-green in the spring, and always with a strong lemon-thyme scent. This Zone 4 woody subshrub usually looks marginal in the spring, but has survived since 2006. At the moment, the rosemarie, garden sage, parsley, tarragon, and hyssop all add a range of green shades and forms to the mostly buggered potager garden. I suppose I should take advantage of them and the last of the garden veggies and start cooking.

    PS – My Geranium macrorrhizum can be more or less semi-evergreen, at least in a sheltered location along the west wall of the house (where it is – believe it or not – shading out and out-competing lily-of-the-valley). In exposed areas it looks pretty sad even now, but for most of the year it is an attractive groundcover and effective weed suppressor.

  11. Northern Shade :
    October 24, 2009 at 4:50 pm

    Dave, it sounds like you have lots still green in your garden. I saw some hybrid Helleborus left at a greenhouse this week, and I debated about trying to plant some this late. They were mixed though, and I like to know the colour of blooms.

    The Blechnum spicant sounds like it is worth trying here, especially for the prolonged greenery. I knew that the sensitive fern would die back when the frost came, but I didn’t know it would succumb when it was only sweater weather. I don’t think I’d plant more than one in such a short growing season, since it was gone at the very beginning of September.

    Thanks for the information on other perennials that keep their leaves. As the dried leaves are being blown away by the strong winds today, I appreciate the ones that have hung around even more.

  12. Town Mouse :
    October 24, 2009 at 7:24 pm

    interesting! in my garden, asarum caudatum an various heuchera have the interesting leaves as well, though our climate is so different. fun post! can’t quite imagine frost yet, though it will come soon enough. a bit, that is.

  13. Northern Shade :
    October 24, 2009 at 9:56 pm

    Town Mouse, Asarum are great looking foliage plants, with such lovely leaf shapes. I will have to check out A. caudatum. Heuchera sure pull their weight in the garden, until the snow covers them.

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