Friday, April 4, 2014

Consider Caryopteris

Today was a bit drizzly with overcast skies and a temperature around 40 degrees F.  We spent the day with a variety of important indoor activities including office work, painting and more Holiday Lights Show (HLS) processing.  We had a small but talented crew today.  Big John and Pat worked on processing HLS items and really opening up some space in the Horticulture Center which is still suffering from "winter congestion."  We've been doing so much carpentry, painting and other projects that it was a good day to tidy up and prepare for a busy spring.  Janice worked on the Thomas Jefferson Collection labels among other projects and I'm still finalizing orders and event details (including me!).  Our Compost Sale starts tomorrow (8 am - 12 noon) at the Horticulture Center where bags (1.5 cubic ft., 45 lbs) of blended mushroom compost are on sale for $6 each (plus tax).  RBG Members get a 10% discount!  Nancy N. and Dr. Gredler were in for obelisk painting and we also saw Bev. W, Ron W., Maury and some others.

I'm featuring a plant that was a very successful component in our Pollinator's Paradise theme in the Nancy Yahr Memorial Children's Garden in 2013.  Frequently called blue mist spirea or bluebeard, Caryopteris sp. is a late summer blooming plant that I consider a "sub shrub" in our climate.  The stem growth is woody and may overwinter and re-foliate depending on snow cover and the severity of winter.  There is frequently some stem die back but spring growth lower on the plant or at ground level will fill out quickly with flowers starting typically in late July and extending until frost.  On occasion, these plants will die and are hardy to zone 5.  They are worth growing though and are quite low maintenance.  If you are wary of bees for any reason, don't plant these as they are a magnet for bees, butterflies and other pollinators.  The variety above and directly below is 'Dark Knight' which is one of my favorites. 

Native to Southern and Eastern Asia, this plant has 16 species although the most popular bluebeard "in the trade" is Caryopteris x clandonensis which is a cross between two species (incana x mongholica).  There are many select varieties of this hybrid with most getting 3'-4' tall by mid-summer.  Preferring full sun and well-drained soils, this plant is drought tolerant and is a very strong bloomer for 2-3 months.  I'm partial to the variegated varieties like 'Summer Sorbet' seen below.  There are some good golden foliage selections too although hot, dry summers might create some leaf browning.  'Worcester Gold' has been around for many years although 'Sunshine Blue' (see further below) is the new standard with foliage that rarely burns and a solid contribution of flowers.  I'm also a big fan of the variegated bluebeard 'Snow Fairy' (Caryopteris divaricata) which can get quite large but offers wonderful variegation and an "almost white" appearance.  Small blue flowers emerge very late in September although the foliage is a contributor from May until hard frost.  The large specimens photographed below are at Olbrich Botanical Gardens in Madison, WI where maturity contributes to these 4' tall and 4' wide "spheres of color."  Consider Caryopteris in your full sun garden and come see our specimens at RBG with a strong focus in the "Pollinator's Paradise."

'Summer Sorbet'
'Summer Sorbet'
'Sunshine Blue' (photo from Song Sparrow Nursery)
foliage of 'Sunshine Blue'
'Snow Fairy' (mature specimen at RBG)
'Snow Fairy' (young specimen at Olbrich Botanical Garden - OBG)
'Snow Fairy' at OBG
'Snow Fairy' at OBG
misc. Caryopteris in full bloom in late summer

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