Dark Knight Blue Mist Spirea with brown spots #460658 - Ask Extension

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Dark Knight Blue Mist Spirea with brown spots #460658

Asked June 08, 2018, 10:12 AM EDT

Full name: Caryopteris clandonensis Dark Knight Blue Mist Spirea

The plant was very healthy when I bought it.  I planted only two weeks ago, in an area with sun from the morning to about 2 pm.  The soil is quite alkaline, a soil test shows pH is in the range of 8.0  (please see attached picture).    Water it regularly, once a day.   

This morning I noticed there are brown spots on the leaves (please see attached picture).  Please advice what the problem is, and how I may protect my plant.  

Frederick County Maryland

Expert Response

These spots are made by the feeding of a four-lined plant bug, a common occurrence this time of year.  Because there is only one generation of this insect a year, it is not around long and its damage is minimal, no treatment is necessary.  New growth covers the spots.  

Here is more info: http://extension.umd.edu/hgic/plant-bugs-flowers

ECN

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