Persicarias are one of those overlooked plants that, should they be grown, tend to be used as fillers or ground cover. Once called polygonums, I want to put the case for using them simply for their quiet proud beauty, the usefulness as foil, the whole length of the flowering period and for their gracefullness.
All persicarias (or bistorts) produce long, thin spikes of tiny round flowers in profusion. Whether you choose the short, carpeting types or the larger mounding ones the weed excluding mound of foliage that is covered for many months with a sea of upright flower stems. The flowers, especially the longer stemmed ones, can be cut for using in a vase and look wonderful placed with more blousy garden flowers such as phloxes. This is also true of them when placed in a border. I love them with Phloxes, especially the pink and purple ones such as Phlox paniculata ‘Uspeck’ and Asters like Aster x frikartii ‘Monch’. The larger varieties are ideal for placing at the back of a border, or under shrubs providing the soil is not too dry.
They are so easy to grow, great for shadier spots in the garden as well as sun, but they do need a soil that does not dry out during the summer months.
Tall Persicaria amplexicaulis varieties
All the tall persicarias are variants of Persicaria amplexicaulis, a plant that grows wild from the Himalayans right into China. They produce a dense mound of large, dock-shaped oval leaves from which spring long stems that end in slender spikes of tiny flowers. They start to flower during mid July and go on well into late autumn. They all grow from 75cm to 120cm
Persicaria amplexicaulis ‘Atrosanguinea’ is the original red flowered variety with deepest crimson flowers. Grows up to around 120cm
Persicaria amplexicaulis ‘Firetail’ has bright red flowers
Persicaria amplexicaulis ‘Taurus’ tends to be shorter than the ones above and has slightly fatter spikes of dark red flowers. Grows to around 90cm
Persicaria amplexicaulis ‘Rosea’ produces slender spikes of pale pink flowers – very pretty
Persicaria amplexicaulis ‘Jo And Guido’ is an excellent variety with glowing rich pink flowers
Persicaria amplexicaulis ‘Alba' is the only white flowered variety I know. The flower stemsa are bronzy, which brings an added dimension to this lovely plant
The shorter persicarias are very useful for the front of the border. Three varieties are generally, but they look all the same to me. The one we sell is Persicaria affinis ‘Superba’ which produces a dense carpet of small, rabbit ear shaped, deep green leaves that is more or less evergreen. From this springs lots of reasonably long, fat flower stems of tiny white flowers that become deep pink with age, giving it a two-tone effect.
What goes well with persicarias
I think the best companions for persicarias are bold plants, such as Aconitums with tall upright stems of bright blue flowers; Asters such as Aster x frikartii 'Monch' which flowers from the middle of August well into autumn; Geranium 'Rozanne is nice as a front of border plant with the bigger persicarias. Short Persicaria affinis 'Superba' goes well with any low growing plant, but as it is vigorous is better with other strong growing plants such as Stachys byzantina.
by Claire Austin
Posted on 08/10/2011