Rampant fantasy – with update
Some plants strike fear in the hearts of gardeners. Vinca, lamium and ivy are all plants some people would not consider planting in their gardens. Close behind comes the polygonum clan which includes lots of weedy species, thugs like Japanese knotweed and some really good garden plants. One useful feature of some of them is that the plants are often either male or female so individual specimens cannot set seed – a great relief when it comes to plants such as Japanese knotweed which would otherwise take over the world. Most are herbaceous and have fleshy stems with alternate leaves up the stem, usually with clasping bracts at the base that sheath the stem. Most have lance-shaped or heart-shaped leaves in mid green and reddish stems and tiny flowers in clusters or spires that are either white, pink or red. Most of the garden-worthy forms are good, solid garden plants rather than garden stars. Most prefer rich, moist soils and sun or part shade and some have red or brown ‘V’ marks on the leaves. Tovara virginiana is a useful plant with insignificant flowers and reddish ‘V’s on the leaves but the splashily variegated ‘Painter’s Palette’ is the form you are most likely to find. Although it is undeniably bright and showy I am not a fan – it looks as though someone has thrown up on it to me. Another reason why people shy away from this group of plants is that botanists keep on changing their names so you can’t be sure if the plant you want is a fallopia, persicaria, polygonum or reynoutria, among others.
The testosterone-filled but well behaved P. polymorpha looking beautiful in July
Since I have been in Ireland I have discovered the amazing Persicaria polymorpha (which I will feature later) but last year I also added the interesting Persicaria ‘Purple Fantasy’ to the garden. Because I have a lot of space to fill in a short time and the soil in most areas is on the heavy side and usually moist, persicarias are useful to me. Polygonatun campanulatum is thriving in a shady border and P. bistorta and P. amplexicaule are filling other voids. ‘Purple Fantasy’ is a newish form of P. microcephala (meaning ‘small head’). The wild plant seems to be native to Asia although that is a bit vague! The most popular form is ‘Red Dragon’ which has attractive reddish – purple leaves marked with grey. It apparently originated at Crystal Palace Perennials in Indianna (USA) and was introduced by the company’s President, the late Greg Speichert who described the blooms as ‘white popcorny flowers’. ‘Red Dragon’ comes through the ground a bit late sometimes but quickly builds into a dome of rich, beetroot-coloured foliage. Sometimes the colour ages a bit to coppery and it can get a bit lose in habit by late summer but by then it is spotted in the small clusters of tiny white flowers. No one will get very excited about these but they are useful for bees, butterflies and flies that want some autumn nutrition. I would put it in part shade for best colour and results but it really is pretty hard to kill. In my experience this does not run or set seed, despite what you may read elsewhere and when a part of the garden got overrun by weeds it survived being swamped by a vicious team of brambles, ivy and goosegrass but did not move from its allotted spot.
The remarkable foliage of ‘Purple Fantasy’
New to me is ‘Purple Fantasy’. I do not know where this came from but it appears to be European in origin rather than American. I am not sure what fantasy the raiser was having when he (or she) named it but purple it ain’t! It is difficult to describe the leaves because they are a confusing confection of grey, green, claret and red (ish). Some reports also say that the stems do not last well in water but I have found it does take up water and it makes a good foliage for cutting.
Just one year after planting a clump is almost 1m across
It makes a big clump of leaves. My plants have been in the ground less than a year and are getting huge. They are now almost 1m across and I will have to divide them next spring. That won’t be a problem because it means I will have lots of plants to spread around the garden to keep down weeds and bring lots of colour to dull areas. This may not be the best plant for a small garden but where you have space it is a useful filler.
Update: April 2015
Well, how my opinion of this little thug has changed! I have just dug the two clumps out of the border. Not only have the clumps themselves expanded hugely but there are small plants, from suckers or creeping stems, coming up at least 60cm away from the main plant. This is too much of a good thing! So it is all coming out (I hope) and going in some wilder areas of the garden where it can fight it out with nettles and ground elder! You can’t say you have not been warned!
Update September 2015
And more info! Although the plant is hardy a late frost killed all the new foliage down to the ground, but it sprouted again. Although I thought I had dug it all out there were lots of creeping stems that I had left behind so the clumps are as big as last year. After more research I think this plant may be P. runcinata. Whatever it is I am learning to hate it.
The Biking Gardener 
Just bought this because I loved the leaves. I planted it yesterday but think I’ll stick it in a pot now (I’ll try treating it like mint). Thanks for the warning!
I would be very cautious with it! Glad to have helped!
Thanks so much for sharing your experience! I was about to plant it in a newly cleaned out shady spot (it took 4years to dig out invasive acanthus). I will find a pot for it instead.
You are a star.
this may sound odd but I have found that most “spreaders” are still viable in the garden as individual plants and controlable if planted in the exact oppostie conditions to what they require . That is to say if a plant requires full sun , plant it in shade and vice versa. This seem to slow plants down that are so very aggressive in my gardens.