Late Summer Blues: by Tom Butzler

I was walking through my landscape and the Penn State Trial Garden last week enjoying the sights and sounds. Plants seem to be in pretty good shape, compared to last month, with the onset of cooler temperatures and frequent rains. One thing that stood out to me as I walked about was the color blue. Of the primary colors in the landscape, blue and violet are considered cool compared to the warm colors of red, orange and yellow. Cool colors are considered relaxing and soothing.



Pollinators loves visiting the
light blue flowers of the blue
mist shrub.  Click on photo
to enlarge

 The small shrub that stands out in my front yard is bluebeard or as some others call it, blue-mist shrub (Caryopteris x clandonensis). It is only about two feet high with bright blue flowers borne on upright branches. My place gets full sun all day long so this plant is situated well; less sun or shade results in fewer blossoms. Although it is woody plant, a gardener should treat it as a perennial. Flowering occurs on new growth only, so it is important to cut back in the late winter.

Chaste tree (Vitex agnus-castus) takes about a bit more space compared to bluebeard. This originated in the Mediterranean which is a bit warmer in the winter than central Pennsylvania. Further down south (Georgia, Florida), this is grown as a 10-25 foot tree. We will never see that height in our landscapes as most of the plant dies back to the ground.

Vitex.  Click on photo to enlarge.

Occasionally a branch or two may make it through the winter. I usually wait until late-spring to see what portion of the plant died and what made it through. Any branch that might not make it through the winter is pruned out once the bush has broken dormancy which can be quite late in spring. The appearance in my landscape is a rounded mound that is 6 feet high and the same spread. The flowers are bright blue and somewhat fragrant and are borne on a panicle that is around 8 inches long.

A favorite that had been used heavily in the landscape industry is Russian sage (Perovskia atriplicifoli). I think this has been mostly a result of being named the 1995 Perennial Plant of the Year. This plant comes out of the Afghanistan/Tibetan region, a hot dry region.



Russian sage in the forefront
with a mass planting of
Karl Foerster's feather reed grass,
(Calamagrostis x acutiflora 'Karl Foerster')
in the background.  Click on
photo to enlarge

 Russian sage reaches a height of 4-5 feet with a similar spread. Its light blue flowers are borne on 15-18 inch spikes and flowers well into the fall. Even before it flowers, it stands out a bit with its silvery green foliage. I suggest you prune this back in the spring, otherwise the plant can take on a floppy appearance over the years. Although this works well as a specimen plant (only one plant), I think it is most effective when planted in groupings.

My house gets full sun all day long as a result; I need plants that can take the heat. These three late flowering shrubs not only add color as the summer winds down but add a calming effect to the garden.