Identification: Serrula - Tibetan Birch Bark - small white singles, green leaves, mid-season

Discussion in 'Ornamental Cherries' started by wcutler, Apr 23, 2007.

  1. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

    Messages:
    8,601
    Likes Received:
    967
    Location:
    Vancouver, BC Canada
    This is not a question, but comments and corrections are very welcome.

    The one specimen I've seen of this tree, on private property on Comox St in Vancouver's West End, looked totally dead for most of the cherry blooming season and hardly fits the description usually given for these trees: "magnificent bark", "spectacular all year", "attractive on any score". This is actually one ugly tree, mostly because of its heavy, clunky, heavily pruned looking limbs and spindly branches. And the bark's not all that shiny either.

    Still, it was easily recognizable by the peeling bark. The teeny white single flowers have more stamens than you would think could fit on one little flower, and they're long stamens, showing out below the drooping and never quite opened petals. The green leaves open with or before the flowers. It's supposed to bloom mid-season, but it didn't bloom this year until late season (though I did miss its peak bloom in these photos).
     

    Attached Files:

    Last edited: Aug 22, 2020
  2. Douglas Justice

    Douglas Justice Active Member UBC Botanical Garden Forums Administrator Forums Moderator VCBF Cherry Scout Maple Society 10 Years

    Messages:
    990
    Likes Received:
    36
    Location:
    Vancouver, Canada
    Re: Serrula - Tibetan Paper Bark - small white singles, green leaves, mid-season

    Like other Prunus species, P. serrula (also known as birch bark cherry) is susceptible to bacterial canker and blight (same disease, different tisues affected) in this climate. The bacterium responsible (Pseudomonas syringae) is a highly infective organism--technically, there are numerous strains of this bacterial species, some of which are highly virulent on cherries--easily spread by rain or running water and introduced into susceptible tissues, such as flowers, frost cracks and pruning wounds.

    Bacteria overwinter on plant surfaces, particularly in crevices and on infected tissues, as well as systemically, in seemingly healthy tissues. Infection usually occurs in spring, and is facilitated by cool, wet weather (no shortage here) and an opening, which can be natural or otherwise.

    Siting has a great influence on the degree of infection. For example, drips from trees, wires or buildings overhead can help spread bacteria (as well as disease causing fungus spores), and limited air circulation can provide the high humidity that promotes infection. In tight nursery rows, wind-whipped foliage is a significant vector of the disease, and physical rubbing, such as happens on street plantings by passing vehicles can be a serious problem with some cherries.

    Susceptibility to bacterial diseases caused by Pseudomonas varies from species to species, but one of the most susceptible plants is our old friend P. avium (mazzard or sweet cherry). Grafted cherries are therefore under an even greater threat, as a diseased understock may be the source of a systemic infection by Pseudomonas. It is a matter of debate, however, whether sloppy pruning or grafting on mazzard understocks is the greater culprit. To be sure, pruning an infected plant will help to spread the disease, not to mention ruin the natural line and beauty of the tree.

    The plant shown above appears to be grafted (at a weird height, no less) on P. avium. I am not surprised that it looks as poorly as it does. A better strategy for this species might be to grow it from seed (or cuttings--although such tissues might already be infected) and plant it in an open situation. The bark will remain shiny (it can be spectacular) if people are allowed to rub the bark with their hands. This is a picture of a tree (grown from seed) in the UBC collection, taken a few years ago by Daniel Mosquin, our bioinformatics and web manager. The tree is now over-shaded and not nearly as clean and healthy as it once was.
     

    Attached Files:

    Last edited by a moderator: Aug 22, 2020
  3. Ron B

    Ron B Paragon of Plants 10 Years

    Messages:
    20,350
    Likes Received:
    386
    Location:
    WA USA (Z8)
    Re: Serrula - Tibetan Paper Bark -small white singles, green leaves, mid-season

    As a group cherries are short-lived trees of open, sunny sites in the wild, often appearing after a disturbance. Locally native bitter cherry probably pretty representative, popping up with alders and other seral species in clearings, only to develop conspicuous gummosis and die out rather young. (Specimens east of Cascades, while mostly shrubbier look generally more thrifty and fruitful than over here).
     
    Last edited by a moderator: Aug 22, 2020
  4. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

    Messages:
    8,601
    Likes Received:
    967
    Location:
    Vancouver, BC Canada
    Re: Serrula - Tibetan Paper Bark – small white singles, green leaves, mid-season

    I was probably unfair to the poor old thing. Here are two other photos from the same tree.
     

    Attached Files:

    Last edited: Aug 22, 2020
  5. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

    Messages:
    8,601
    Likes Received:
    967
    Location:
    Vancouver, BC Canada
    Re: Serrula - Tibetan Paper Bark – small white singles, green leaves, mid-season

    The poor Comox St tree has been removed. I feel bad about speaking so unkindly about it. It didn't look all that bad once the flowers and leaves appeared.
     
    Last edited: Aug 22, 2020
  6. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

    Messages:
    8,601
    Likes Received:
    967
    Location:
    Vancouver, BC Canada
    There are not many identifying photos here, so I'll add some. This is one of two trees that Douglas Justice declared pathetic-looking, in Stanley Park on the divided bike and walking path east of Lost Lagoon. I think it looks not too bad once the (very skinny) leaves come out. Serrula are the last ornamental here to bloom, even later than 'Shirofugen'. You can't really tell they're in bloom (tree in first photo is in bloom), and the blossoms last about a week. When you consider that all there really is that's ornamental is the bark, since the bark is shaggy but not shiny on these two, they don't have that much to recommend them. I've seen two really nice ones in Seattle
    20100425_StanleyPk_Serrula_Cutler_P1010341.jpg 20100425_StanleyPk_Serrula_Cutler_P1010345.jpg 20100425_StanleyPk_Serrula_Cutler_P1010349.jpg 20100425_StanleyPk_Serrula_Cutler_P1010354.jpg

    These two photos are from May 5, 2008; the first four are from April 25, 2010.
    20080505_StanleyPk_Serrula_Cutler_5574r.jpg 20080505_StanleyPk_Serrula_Cutler_5579r.jpg

    This tree in Seattle demonstrates more of what people get excited about.
    20100221_22ndAveNE63rdStNE_Serrula_Cutler 005.jpg 20100221_22ndAveNE63rdStNE_Serrula_Cutler 006.jpg 20100221_22ndAveNE63rdStNE_Serrula_Cutler 007.jpg
     
    Last edited: Apr 25, 2010
  7. Dingren

    Dingren Active Member VCBF Cherry Scout Maple Society

    Messages:
    219
    Likes Received:
    0
    Location:
    Richmond, BC
    Re: Richmond

    Birch Bark Cherry

    Here i took 6 photos of birch bark cherry blooming in three locations: the first two were taken in Stanley Park on May 4, the second (1st row left) in Vandusen Park on May 6 and the last two (2nd row) in General Currie in Richmond.
     

Share This Page