Hedges: Arborvitae thinning out. Prune?

Discussion in 'Gymnosperms (incl. Conifers)' started by IrishAirWolf, Apr 10, 2005.

  1. IrishAirWolf

    IrishAirWolf Member

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    I have a 100 + foot hedge of arborvitae across the back of my yard, a privacy hedge. The plants are about 20 years old and 15 feet high. I have noticed that the lower sections are starting to get male pattern baldness of a sort, they are getting thin. I need the botanical equivalent of a comb-over. Will they bush out in the lower sections if I top them? I had them pruned once where the person hedge trimmed the front of the lower section and it took some time for it to recover and did not improve them.
     
  2. Newt

    Newt Well-Known Member 10 Years

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    Hi Irish,

    Topping them won't get them to fill in. You will need to hand prune to green growth to get them to fill in. Shearing or cutting back to old wood with no greenery will only make them stay that way. From this site:
    http://www.emmitsburg.net/gardens/articles/frederick/2003/prune_evergreen.htm

    "For those of us with plants that need some reining in, there is a basic rule of thumb for ever-greens: Sun-loving conifers, those whose needles all need sun, can be pruned annually, but only gently within the living green foliage. This type of ever-green does not have green needles in the interior of the plant. Most do not even have growing buds on interior branches. As a result, if you prune that plant hard, into old wood, once it has become extremely over-grown, you will end up with an ugly brown bare spot in your tree or shrub. Most junipers and arborvitae fall into this category."

    "The arborvitae will probably never make a great topiary if it is already over-grown. If it is still small enough you may try pruning, but remember, cut only into the green areas of the shrub."

    Newt
     
  3. Ron B

    Ron B Paragon of Plants 10 Years

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    As with male pattern baldness, scalping will not result in more hair. Try to find a similarly aged specimen or hedge on another property and see if it looks denser. If so, then that suggests that yours may require a cultural improvement, such as mulching or irrigation to look more attractive. Arborvitaes are much more open and thin on poor sites than good ones.
     
  4. Newt

    Newt Well-Known Member 10 Years

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    Ron, so Irish shouldn't prune at all?

    Newt
     
  5. Ron B

    Ron B Paragon of Plants 10 Years

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    Hard to say without looking at them, knowing other details like if they are exceeding the space.
     
  6. IrishAirWolf

    IrishAirWolf Member

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    Picture of the arborvitae hedge in question.

    This is not the greatest picture but you can see the hedge pretty good. The thinner spots are not in this photo, as it is several years ago. The shrubs were planted the same time as 3 individuals that are not in the hedge but are planted separately in the garden which are probably 3 times the size around. I presume the ones for the "hedge" were planted too closely together but we bought the house with the hedge already started. (It was about 4 feet high at that time.) We spray for spider mites and water when the weather is really dry and fertilize. Someone else suggested planting a new small shrub in front of the bare spots but it is difficult to dig in the root system these things put out.
     

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  7. Ron B

    Ron B Paragon of Plants 10 Years

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    As expected, they need something - and pruning isn't it. They might need mulching, they might need irrigation, or there could be a pest or pathogen making the lower parts gaunt. There are fungal blights that afflict arborvitaes, as well as root rots tht may cause the top to deteriorate in sections, plus sucking pests that cause sections to deteriorate. We aren't nearly close enough in this view to have any specific idea. Try taking samples to a local source of help for suggestions. Down here that would be an Extension office, Master Gardener Clinic or good independent nursery, for example.

    After you tackle this problem do consider not pruning all the branches off of your fruit trees.
     

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