Identification: Crab Apples - red buds, white blossoms, green leaves, late cherry season

Discussion in 'Ornamental Cherries' started by wcutler, Apr 21, 2007.

  1. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    This is not a question, but comments and corrections are very welcome.

    I remember a newspaper article a few years ago that said that most people think the crab apples are cherries (I just met one of those people today), so I’m including them here for information. There seem to be hundreds of these trees in the Vancouver West End.

    The crab apples are mostly small (the one's I've seen), round-shaped densely branched trees with green leaves fully out about a month before the buds are clearly visible. The bark does not have the cherry tree horizontal stripes. The dense clusters of bright red buds that stand out against the green leaves make the tree look like some sort of Christmas ornament. The smallish single white blossoms are an anti-climax, though the trees still look interesting with both buds and open blossoms. There are some varieties that open to much more exciting deep pink single blossoms.
     

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  2. Douglas Justice

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

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    These are lovely trees when the conditions suit them. Like so many spring flowering plants, this year seems to be extraordinary with respect to floriferousness and freedom from pests and diseases.

    Good spring flowering depends on bud set. A number of factors are required for this, including adequate wood ripening, a period of winter dormancy and adequate chilling. Tissues have to be physiologically mature to form flower buds, and they need the correct combination of heat, light, moisture and nutrition to do this. In this climate, which is characteristically cool and wet except for a short period in the summer, many plants (including crabapples) fail to flower as well as they do in more continental climates.

    Poor flowering is common with such plants if they receive inadequate sunshine and/or too much or too little moisture the previous summer. Summer is when flower buds are formed. If we have dull, rainy weather in July and August (which can occasionally happen), flowering is even lousier than normal the following year. Exceptionally mild winters, which are generally the norm here, also have an effect on how plants both enter and emerge from dormancy. If the weather is too warm and wet in the autumn, some plants just don't properly shut down for the winter. This can be a serious problem if we then have a sudden drop in temperature (as we did last November). In other words, plants need to be adequately "hardened off" to survive the rigors of winter.

    Further, most temperate flowering plants have a specific "chilling requirement" (the amount of cold a plant needs before it can resume normal growth in the spring). This may not be adequately met in the Vancouver area for some plants adapted to cold winter climates. I liken it to sleep requirement in people: Some can do with less sleep than others; however, if the alarm goes off early, those who need a lot of sleep are able to function, but may not be at their best.

    The early freeze in November, which was followed by cold temperatures in December, January and February (for once, it actually felt like winter here) probably killed off a variety of caterpillars (e.g., bruce spanworm, winter moth), and undoubtedly satisfied the chilling requirements of many plants that normally perform poorly here. With cherries, whose chilling requirements are not so great, their good showing was probably more due to good bud set last year and an absence of disease this spring. I'm surprised that brown rot and bacterial blight haven't taken a toll, given the horrendously wet weather we had in March; however, it may be that the temperature was just not high enough during the wet weather for those organisms to infect tissue.

    Unfortunately, scab and powdery mildew (among other diseases) are rampant, and will badly disfigure and defoliate crabapples (and hawthorns) before the season is out (unless it doesn't rain). This is the reason they're not more widely cultivated here.
     
  3. Ron B

    Ron B Paragon of Plants 10 Years

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    Resistant cultivars are available.
     
  4. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    I'm posting here the Pacific Crab Apple, Malus fusca, which managed to confuse me twice last week while I was looking for Prunus emarginata, as this native tree looked a lot different to me than the ornamentals on so many of our streets.

    Jill Taylor, steward of the
    Stanley Park Ecology Society Native Plant Demonstration Garden, sent me this description from Pojar and MacKinnon's Plants of Coastal British Columbia: "M. fusca are described as having '[leaves] alternate, deciduous, lance- to egg-shaped, to 10 cm long, pointed at the end, toothed, with irregular lobes; turn red or yellow-orange in fall', with flowers 'White to pink, showy, fragrant apple blossoms, about 2 cm across; 5-12 in flat-topped clusters on spur shoots.'"

    The first photo is Jill's, of the tree in the Demonstration Garden, taken May 9, 2009. It was planted in 2003, and this is its first year to flower. The other photos are mine of the same tree taken on May 15. The leaves at the bottom of the trunk are from something else.
    20090509_StnlyPkDEmoGdn_Crab_Taylor_003.jpg
    20090515_StnlyPkDemoGdn_MalusFusca_Cutler_DSC03515.jpg 20090515_StnlyPkDemoGdn_MalusFusca_Cutler_DSC03518.jpg 20090515_StnlyPkDemoGdn_MalusFusca_Cutler_DSC03523.jpg 20090515_StnlyPkDemoGdn_MalusFusca_Cutler_DSC03525.jpg

    These 2cm blossoms are about twice the size of P. emarginata blossoms, the leaf edges are a lot more toothed and irregular, and the blossoms are not in such tight pompom balls.

    On some ornamental Crab apples this year, I've seen some blossoms that were about 5cm in diameter.
     
    Last edited: May 17, 2009

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