The Best of 2010: Part 1: Knowing the Knotweeds

I'm becoming very fond of many selections of Persicaria that are out there. Their bold and often dramatically marked foliage are so eye-catching and the spikes of bright red are fun and add a nice surprised come summer. I find in kind of unfortunate that they're related and often mistaken for their close relatives Polygonum cuspidatum (Japanese Knotweed). The ornamental Persicaria (the most common being selections of P. amplexicaulis and P. virginiana), though known to also be quite aggressive and vigorous, are manageable and easy to maintain.


Here's Persicaria amplexicaulis 'Taurus'. A fine border plant for full sun that forms dense, almost woody clumps of lush foliage and abundant spires of red flowers that form in early summer and after that first flush which ends in mid-summer, the plants are sheared back to the ground for a second round of fresh foliage and then MORE flowers that often last until frost! Mature plants can spread 4-6ft. wide and the flowering spikes rise up to about 2.5ft. They're wonderful fillers in flower arrangements!



A brand new and exciting selection (at least to me!) I've acquired this year is one that seems a bit tidier and a smaller version of the above, but with glowing chartreuse foliage. This one was dubbed 'Golden Arrow'. I purchased a division from my friends at Far Reaches Farm in Port Townsend, WA and I've been very pleased with it's habit. Now, it's only the first year and it's not really in the richest or moistest spot in the garden, but I see this as being a very attractive and useful plant in part to full shade, although it gets its best golden foliage in full sun.



P. 'Red Dragon' is a selection of P. microcephala and TALK ABOUT FOLIAR APPEAL! As gorgeous as these leaves are, it is kind of a rambunctious plant, but the great foliage color and weaving habit and small clusters of white flowers late in the season make it a fun and welcomed addition in the garden. Should it get out of bounds, just whack it back to the ground and prepare for a nice flush of new foliage!




Here's one that we don't see too often, but it is quite striking. This one is referred to as 'Compton's Form'. The flowers on this aren't really that spectacular, but for foliage, it's quite dramatic. This photo shows off the early season color in full sun, but grown in shade, the leaves are bigger and you get this effect:



And finally, one I'm quite fond of, but not many local nurseries here carry it is this selection called 'Brushstrokes'. It's not as busy or overly dramatic in terms of color, but the painted "chevrons" and HUGE leaves are so bold and attractive.



There's way more out there that's available, but these are just some of my favorites in the garden this year!


R