The color blue brings peace and tranquility to a garden. Clematis is one of the few flowers which incorporates so many shades of blue. With almost a thousand different blue clematis described on Clematis on the Web it may be difficult to make a choice. Clematis 'Vistula' has been outstanding in my garden. The strong clear blue has a bewitching allure which draws me to it as I meander through the garden.
The 2.5 to 3 meter (8 to 10 ft) vine is covered in textured flowers with prominent mid ribs along the elliptical tepals which have wavy margins and end in sharp points. This gives the illusion of celestial stars floating on my trellis. In my hot climate of Atlanta, Georgia, it starts to bloom in May but in more moderate climates it is considered a late large flowering clematis which peaks later in the summer. C. 'Vistula' is classified as a group 3 pruning which adds to its usefulness so you can prune it back at the end of the season as it will bloom on new growth. In some climates the blue may appear as more purple blue than clear blue. Either shade of blue is enhanced by the bright yellow anthers on creamy filaments.
C. 'Vistula' was introduced in 2009 by renowned horticulturist Szczepan Marczyński. In 1994 he made several controlled crossings as well as collecting a mix of seeds (open pollinated) from C. 'Mrs. Cholmondeley', C. 'William Kennett', C. 'Jan Paweł II', and C. 'Kardynał Wyszyński'. He then sowed the seeds in the spring of 1995 leading to many seedlings in 1996. The seedling numbered 1969-95 first flowered in 1997 and Szczepan noticed its nice blue flowers. With many blue seedlings, he was uncertain if it was worth naming and introducing but he continued to observe it as thousands of others did not prove to be worthy. After 10 years of observations in several places, Szczepan reports that he was seduced by the clear blue color and long flowering at the beginning of August when there are no abundantly flowering clematis in the Polish climate. It was also healthy and strong growing.
In 2009 he named it C. 'Vistula' after the picturesque main river in Poland which flows through Warsaw. In 2010 this special clematis was awarded the Bronze Medal at the Planetarium Trade Show in Boskoop, Holland. The following year it was introduced to the market. With Szczepan's fine eye for combinations, he grows C. 'Vistula' over Chamaecyparis filifera 'Aurea'. The frilly blue flowers are a perfect contrast to the chartreuse foliage of the Chamaecyparis.
We are fortunate to have dedicated clematarians who have devoted their lives to the genus Clematis. Szczepan Marczynski is a Past President of the International Clematis Society and founder of Clematis Container Nursery in Pruszkow, Poland. He has introduced over 40 new clematis during his career. It took over 15 years of observation to ensure C. 'Vistula' is a clematis worthy to be planted in your garden.