Caryopteris – Blue Spirea Not!

Unfortunately, some unimaginative nurseryman coined the common name “blue spirea” for this very excellent small shrub. In so doing he unwittingly did the plant a disservice for the name immediately identified it with the ubiquitous Spiraea Vanhouttei which is, perhaps, the most common shrub to be found in the garden and landscape plantings of America.

“Blue spirea” is not a spirea at all. It does not even belong to that family of plants, but rather to the verbena tribe. “Shrubby verbena” would have been a much happier choice of names for this garden ornamental. Therefore, let us ignore the misnomer “blue spirea” and call it by its proper name, caryopteris (pronounced carry-op’-ter-is).

Caryopteria - The Blue Spirea commonly called in flower

Made to Oder

Here is a shrub made to order for the soils and climate of the Great Plains. It takes the cold, drought, heat and everlasting wind that buffets our gardens, in stride. It is quick to grow and produce its long sprays of blue flowers. Plant it in the spring and you can be sure that late July and August will bring willowy sprays of soft blue flowers to brighten the garden and provide material for cutting. These sprays are an arranger’s dream. Even the fruiting stems after the flowers have faded are good arrangement material. Also important is the fact that caryopteris is happy in high lime soils where true spireas turn sick and yellow with iron deficiency.

One of the most well known caryopteris is ‘Blue Mist.’ This variety name is a good choice. ‘Blue Mist’ grows to a height of four feet and makes a bush up to six feet across. It is never leggy or straggling. During late July and August it is literally covered with lacy blue flowers in sprays 12 to 20 inches long.

In addition to ‘Blue Mist’ there is a newer one called ‘Dark Knight.’ It is a seedling of ‘Blue Mist’ but is even hardier. The plant is smaller than its parent, the flowers a little deeper blue, and the foliage is darker green. ‘ADark Knight’ is perhaps the better plant for the low lines of the modern home. Both varieties are good plants for any garden and particularly for difficult locations where they thrive despite wind, drought and poor soil.


Planting and Culture

Plant caryopteris in full sun if possible, although the plants will tolerate shade part of the day. The plants should be cut back to six or eight inches each spring to insure a maximum of the long sprays that are their chief attraction. The shrub is short lived compared to lilac and others of that class but it is so easily propagated that anyone can increase it. Three-inch cuttings of new wood taken in early June will root in days and if given forceful culture will bloom in September. Such cuttings are best started in sand or perlite but even those stuck in soil and kept shaded and moist will root in appreciable numbers. Incidentally, the caryopteris is easy from seed. Seedlings by thousands will come up each spring around the mother plants and are as easily transplanted as cabbage. Seedlings do vary, but most of them are pretty good.

by G Meyers

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