Sorbus alnifolia (Korean Mountain Ash)–PLANT FIX

Sorbus alnifolia gets its name from having leaves shaped like those on an alder. This is one of the species of mountain ash that don’t have pinnate leaves.

Our mountain ash tree has never been happier and neither have the cedar waxwings that call our neighborhood home.  Covered in berries inching toward ripeness, the mountain ash will soon host a grand bird feast.  All the Sorbus are well known for bounteous, colorful berries.  Gardeners appreciate this trait both for brightening the late summer and fall landscape, but also for luring cedar waxwings and other birds.

Until we planted our Sorbus alnifolia in the mid-nineties, we hadn’t seen any waxwings.  It was uncanny how quickly they located the tree which was first planted near our pond and spaced 20 feet from a row of new Douglas firs.  It thrived and bloomed it’s second spring in the ground with plentiful corymbs of white flowers which were lightly scented.  That year the berries were stripped so quickly I missed the whole event.

This year, I’ve been watching the berries ripen so that I don’t miss the activity and the joy of seeing the waxwings gorge themselves on one of their favored foods.  We are blessed with so many choice bird watching opportunities with our pond attracting many species.  The waxwings are delightful to watch since they flit from tree to tree in small flocks and snap up insects in mid-air.  The clicking of their short but sharp beaks can be heard as they fly.  Another mosquito gone.  Go waxwings, go!

Korean Mountain Ash still lopsided from years of poor light

This summer has been good to the waxwings with plentiful elderberries and red huckleberries and soon, a bumper harvest of mountain ash fruits, oval and rosy pink.  I knew this fall’s crop would be intense as this spring was the tree’s best flowering in many a year.  In the late fall of 2009 we had hired an ISA certified arborist to move the tree, which was by then at least 12′ tall.  The mountain ash had been outcompeted in it’s original location by the Douglas firs, whose growth rate outpaced the Korean mountain ash, known to be a slow grower.  In time, the east side of the tree was bare from shading and I knew that if it wasn’t transplanted, it would not survive.

This required an air spade, a state of the art tool that uses air to blow compacted soil away from the roots without damaging them.  This technique makes it easier to move and replant large, heavy trees without lugging all the soil in addition to the roots.  It was planted in native soil in the new location and given a thick layer of compost for mulch.  Despite this tender care, the transplant shock was severe and we weren’t sure if it would survive, even as we watered it deeply and regularly the two summers after the move.

Mountain ash backlit by morning sun

Thankfully, the tree has settled in it’s new spot, with much better sun and air circulation.  This spring’s heavy bloom was testament, we believe, to the sunnier exposure and lack of root competition.  As the berries deepen in color, we hope to witness the waxwings’ blissful feast.  Then it won’t be long until the leaves turn their signature russet orange and come spiraling down in a blustery gust.  Gratitude.

See a picture of and learn about Cedar Waxwings at Seattle Audubon Society’s Bird Web at

© Colleen Miko, 2012

About Colleen Miko

Colleen Miko is a certified professional horticulturist with 20 years experience in landscape design who has designed award winning gardens for the NW Flower & Garden Show as well as HGTV’s “Landscaper’s Challenge”. Colleen is freelance garden writer and speaker.
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