Summer flowering trees and shrubs in colder climates

Discussion in 'Woody Plants' started by Milan, Aug 17, 2008.

  1. Milan

    Milan Member

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    I live in zone 6 in the heart of Europe. Having read so many posts in so many web-forums on the internet over the past 6 or so years I would like to share my experience with those who ever came across the same issue: living in a place where winter temperature can easily swing below -20°C some boring gardeners say we are destined to grow rhodes and azaleas, and a few magnolia varieties. I was never happy about this statement so I spent a lot of time selecting and testing trees and shrubs that not only survive or winters but grow happily or even thrive in our climate and flower freely in summer months when most of us want to enjoy the portion of warmth and sun given for a limited time only.

    I know that the hardiness zone does not say it all so here is what we live in: Jan+Feb = usually very cold, often without snow, average lowest -20°C, ultimate lowest -27°C. Mar+Apr can get quite nice and warm with warm spells up to +17 and evening/morning frosts -7°C. May + June get quite hot, sometimes hotter than July/Aug; i.e. 20-27°C but in mid May we have to count on the last frosts of about -3°C in early morning. Our summers are dry when it is sunny, and when it rains it can rain for a week in a row. We get the first frosts and snow in late October. So for us this is the typical continental climate.

    Under these conditions I have tried several plants that were said to be tender plus a few reliable ones making a stunning view of a garden that does not stop blooming from June until September. This is the list of those we grow and which proved to survive our winters:

    - albizia julibrissin Ernest Wilson
    - albizia julibrissin Ombrella (-20°C so far)
    - campsis radicans (various cultivars) in tree forms
    - campsis x tagliabuana Indian Summer and Madame Galen in tree forms and as shrubs
    - campsis grandiflora (-20°C so far)
    - hibiscus syriacus (various cultivars) tree forms and shrubs
    - hibiscus moscheutos (various cultivars)
    - magnolia grandiflora Bracken´s Brown Beauty, Victoria, Edith Bogue, Exmouth, Goliath (Praecox)
    - hydrangea paniculata Limelight, Pinky Winky
    - hydrangea quercifolia
    - hydrangea macrophylla Endless Summer
    - hypericum Hidcote
    - abelia x grandiflora
    - abelia Edward Goucher
    - abelia engleriana
    - stewartia pseudocamellia
    - magnolia May-to-Frost
    - agapanthus Blue Giant (with cover)
    - ceanothus impressus Victoria (though loses leaves if insolate in severe frosts)
    - x chitalpa tashkentensis Summer Bells and Morning Cloud
    - caryopteris x clandonensis Grand Bleu
    - catalpa bignonioides Aurea
    - catalpa erubescens Purpurea
    - wisteria sinensis - tree forms and climbing
    - kalmia latifolia - several late varieties including myrtifolia
    - yucca filamentosa

    If you have your own experience from a similar climate I will be more than happy to read about it. Here are afew photos of what it looks like here in summer.

    The plants in the pictures below (in order of appearance):

    1. Magnolia grandiflora "Bracken´s Brown Beauty"
    2. Kalmia latifolia "Silver Dollar"
    3. Campsis x tagliabuana "Madame Galen"
    4. Campsis radicans
    5. Ceanothus impressus "Victoria"
    6. Hypericum "Hidcote"
    7. x Chitalpa tashkentensis "Summer Bells"
    8. Abelia "Edward Goucher"
    9. Abelia x grandiflora
    10. Hydrangea quercifolia
    11. Campsis x tagliabuana "Indian Summer"
    12. Albizia julibrissin "Ernest Wilson"
    13. Hibiscus syriacus "Duc de Brabant" + "Ardens" + "Lady Stanley"
    14. Wisteria sinensis
     

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    Last edited: Aug 19, 2008
  2. Ron B

    Ron B Paragon of Plants 10 Years

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    It would be nice if you would identify the plants in your pictures.
     
  3. Milan

    Milan Member

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    Of course, so sorry - I am new here and I did not realize it would not take the file names as titles. Names added :-)
     
  4. Ron B

    Ron B Paragon of Plants 10 Years

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    If you could type out a list and post it that would be most straightforward. Note also the ceanothus is not a C. impressus cultivar, which it does not even resemble. Fross/Wilken, Ceanothus (Timber Press) give C. thyrsiflorus 'Victoria' a passing mention under C. 'Skylark', noting that many consider the two to be the same. I have planted specimens received as both here for comparison, so far there is no obvious difference but they are still small and new. Lookalike separate introductions of garden plants do occur.

    Are there different cultivars of Chitalpa tashkentensis in commerce there? Here we have 'Pink Dawn' and 'Morning Cloud'. On the page belwo the Summer Bells name is presented as a registered trademark, for the 'Pink Dawn' cultivar perhaps?

    http://www.havlis.cz/karta_en.php?kytkaid=24

    The oakleaf hydrangea looks like the small-growing yellow-leaved cultivar we also have over here.
     
  5. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Great post, thank you for your effort and time.
     
  6. Milan

    Milan Member

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    Ron, thanks for the post. The thing with ceanothus is a getting a bit confusing. When I first got "Victoria" some 4 years ago it was even called thyrsifolius by the nursery guy :-). I looked it up and correcetd it to thyrsiflorus and uploaded this stunning on my website as c.thyrsiflorus "Victoria". Since then I have received several comments about it being impressus rather than thyrsiflorus. I tried to find something on the internet but it looked quite chaotic. And as my producer in Germany insists it belongs to c.impressus I consulted the RHS Encyclopedia and but was yet no wiser. They say that impressus has leaves only upto 1 cm long (mine are bigger) but the shrub grows only 1.5 x 2.5 m (so does mine). And that thyrsiflorus has upto 4 cm long leaves (so does mine) but grows 6x6 m and is upright (mine is low but arching and very spreading). So to get out of this mess I checked the internet for the Skylark variety which you mentioned. And I must say you are right. Everything fits just perfectly - plant size, leaf size, flower colour and suspectibility to winter sunburn. So the bottomline is that Skylark could be a sport of Victoria from which it only differs by its habit - not so erect and rather arching (spreading) and very compact. But still a bit too tender for zone 6 but surviving with good protection (mine survived -27°C under cover!!).

    RE chitalpa. This is my favourite plant. There are 3 varieties of chitalpa on the market here: Summer Bells® which is registered, Morning Cloud is not protected here (is it in America?), and Pink Dawn which is not registered. Pink Dawn was the first available one, gorgeous but it only flowers once - June-July. Unlike Summer Bells® which starts at the same time but either does not finish until September or starts again in mid August. Morning Calm flowers twice, too, and is not pink but has more prominent burgundy red veins in the throat, and the petals are larger with less frilled margins.
     
  7. Milan

    Milan Member

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    My pleasure, it is always great for me to share my findings and ethusiasm with someone of the same interest. You have done a great job putting this all together!
     
  8. Milan

    Milan Member

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    And Ron, the hydrangea is not a yellow-leaved variety. It was sold to me quite a few years ago without a variety name and the light colour of the leaves is caused by too wet a site with not too good soil. Owing to which on the other hand the leaves turn interesting autumn colours very early.

    Such as a liquidambar I have in the summer garden - it virtually sits in water. When I planted it I did not know how much water there is in the soil but it got established well and thrives. The only thing is that already now - in mid August it sarts making autumn-coloured leaves. It is an awsome display of rich carmine red. Mind you, I do not know the exact species or variety, could you tell by the leaves please?
     

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  9. Ron B

    Ron B Paragon of Plants 10 Years

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    C. impressus has smaller parts of different coloring and construction, producing a different aspect than C. thyrsiflorus derivatives like 'Skylark' etc.

    Santa Barbara ceanothus is an upright, spreading, evergreen shrub 4-6 feet tall with a similar width. The dense, arching stems hold wrinkled, dark green leaves 1/4-1/2 inch long. Abundant cobalt-blue flowers form in 1-inch-long clusters, contrasting vividly with the dark green-black foliage in early spring. Russet-red seedpods follow the flowers in late spring and offer a brief ornamental quality before shattering

    --Fross/Wilken

    It looks like a stormcloud in flower.
     
  10. kaspian

    kaspian Active Member 10 Years

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    Milan, thank you so much for the effort you put into this excellent, rather inspiring post.

    It is especially interesting to learn the details of your growing situation. As you aptly note, hardiness zone doesn't say it all.

    I've always loved the global nature of this forum. It is heartening, somehow, to know that people all over the world share this fascination with growing plants, and that the plants outside my own window are also growing in conditions that seem quite exotic to me. If only everything in global affairs was so amicable.
     
  11. Milan

    Milan Member

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    Kaspian, thanks for that. If this thread gets attention I will be more than pleased to continue posting and showing all garden enthusiasts here what is possible in a climate with harsh winters. I am posting a fresh picture from today - summer part of the garden with the pool and gazebo.
    And as joke the same part of the garden from January 2008 :-)
     

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  12. O'Grodnick

    O'Grodnick Member

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    I sure do. Of the tenderish shrubs/trees you might try Clerodendrum bungei and C. trichotomum var. fargesii (the latter currently flowering in my garden near Warsaw, Poland), Choysia ternata, Gardenia jasminoides 'Kleim's Hardy', or some Lagerstroemia cultivars (I plan to test a few - the first I've managed to obtain is 'Raspberry Sundae') or species (introducing L. fauriei to Central Europe would be cool as hell).

    Heptacodium miconioides on the other hand is considered to be very hardy, but you should be delighted with it non the less. A bit similar is obscure and delightful (to my eye at least) Poliothyrsis sinensis (haven't seen it in flower, but it grows well in our local BG).

    Have you tried Cornus angustata in your location? I'm inclined to grow it some day here in Poland.

    It might never bloom for me, but I will be the first (?) person in my country to ever grow Emmenopterys henryi. Getting Oxydendrum arboreum to flower is not such a problem here.

    There are many wonderful species of Clethra you can grow (I grow a few, but am wondering, if it is possible to grow C. delavayi in our part of the world, and should soon try it). Are you interested in the genus Daphne? In my garden there are a handful of those, including Daphne (or Wikstroemia) gemmata, which will be put to the first test this very winter. What about Cistus? You should be able to grow at least C. laurifolius. Don't forget Sinocalycanthus and its hybrids with Calycanthus (I grow 'Venus' and my friend nearby both 'Venus' and 'Hartlage Wine').

    Some folks in the south of my country (near the Polish-Czech border) are experimenting with the likes of Hovenia dulcis, some Ehretia sp., and Tetradium daniellii, but I don't now if you'd find them ornamental enough.

    You are not alone, as you can see :)
     
  13. Milan

    Milan Member

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    Well, that is an interesting list with items worth trying for sure. I searched for gardenia Kleim´s Hardy a few years ago. Got some contact in the USA but they cannot send containerized plants, just bare-roots. And that sounds too risky to me. Do you have one and tried it under your conditions?


    Heptacodium - a friend of mine has one in north of our country and it does well there. It is also one of my targets.

    Cornus angustata is a beautiful shrub and it would be great to be able to grow it here. I saw pictures froma friend in Ireland, huge shrub, very decorative and profusion of berries (fruit).

    I never heard of Oxydendrum arboreum but it looks amazing in the pictures, just the sort of habit which is missing here.

    Daphne - would be nice, never tried.

    Calycanthus - one of our biggest best-sellers. In my garden I have a large specimen of sinocalycanthus. Beautiful but prone to fungi diseases - when it starts flowering in a rainy season it turns ugly with greeny-black films of some illness. Nevertheless, it is a lovely plant.
     
  14. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Oxydendrum is very difficult to grow, unless you have acidic soil that is also moist but well-drained.
     
  15. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Interesting. We've the same issue with it here at UBC.
     
  16. Milan

    Milan Member

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    But otherwise it is a gorgeous plant :-) I will treat it in early summer next year to prevent most fungi diseases and will see how it responds.
     

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  17. Ron B

    Ron B Paragon of Plants 10 Years

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    I've thought blackening of Calycanthus sinensi I've seen here might be lilac blight. However, it seems it may be associated with full sun exposure, well-shaded plants perhaps not apt to be affected. The wild habitat is said to be notorious for wet, dull weather.
     
  18. Milan

    Milan Member

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    I see, thanks for the thought Ron, will see how it responds to a general fungicide next year.
     

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