Pink Knotweed Uses: Where Can You Grow Pinkhead Knotweed
By: Teo Spengler
Pinkhead knotweed plants (Polygonum capitatum or Persicaria capitata) are considered excellent low-growing groundcover by some gardeners. They are also called invasive pests by others. If you read up on pink knotweed information, you’ll find that the plant is banned in England and considered invasive in California. This is because of its tendency to spread where it wasn’t invited. So can you grow pinkhead knotweed, or should you? Read on for more pink knotweed information.
Pink Knotweed Information
What is pink knotweed? It’s a tough plant that stays under 6 inches (15 cm.) tall but spreads horizontally to up to 5 feet (1.5 m.). It thrives in almost any soil, including dry and sandy soil, and grows in both sun and partial shade in U.S. Department of Agriculture plant hardiness zones 8 through 11.
The lance-shaped leaves of the pinkhead knotweed plants are between 2 and 11 inches (5-28 cm.) long, edged with dark red, and marked with burgundy chevrons. The leaves grow on prostrate red stems that root at the nodes. In mild regions, the leaves are evergreen, staying on the plant all year long.
The pink pompom flowers, each about 2 inches (5 cm.) long, bloom from spring through the first freeze. They cluster in globe-shaped flower spikes above the foliage.
Another way to answer the question “What is pink knotwood?” is to call it a cousin of Japanese knotweed. It lacks the exotic beauty of Japanese knotwood, but still looks appealing growing in the backyard as groundcover.
Where Can You Grow Pink Knotweed?
Groundcover is only one of the many potential pink knotweed uses for those choosing to grow the plant. You can also use pink knotweed in potted arrangements, grow them in baskets, or use them as edging in a border. The plant looks especially lovely in raised beds or containers where it can spill over the edges (and control its spread).
Pinkhead knotweed plants are easy to grow in your garden or backyard. If you live in a region with a long growing season, start the seeds outdoors in weed-free soil once the risk of frost is passed. In areas with short growing seasons, start them indoors.
Fill small pots with good seed-starting soil. Moisten the soil and press in the seeds. Keep the soil moist until you see the seeds sprout. If you start them inside, harden off the young plants for at least 10 days before you transplant them outdoors.
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Persicaria Species, Japanese Knotweed, Pink Bubble Persicaria, Pink Knotweed, Pinkhead Smartweed
|Genus:||Persicaria (per-sih-KAR-ee-uh) (Info)|
|Species:||capitata (kap-ih-TAY-tuh) (Info)|
Average Water Needs Water regularly do not overwater
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
USDA Zone 10a: to -1.1 °C (30 °F)
USDA Zone 10b: to 1.7 °C (35 °F)
USDA Zone 11: above 4.5 °C (40 °F)
Where to Grow:
Grow outdoors year-round in hardiness zone
Suitable for growing in containers
May be a noxious weed or invasive
Soil pH requirements:
From herbaceous stem cuttings
This plant is said to grow outdoors in the following regions:
Manhattan Beach, California
Rancho Palos Verdes, California
Hawaii National Park, Hawaii
Yellowknife, Northwest Territories
On Oct 15, 2018, JennysGarden_TN from Collierville, TN wrote:
Persicaria capitata is now in full bloom in my zone 7b garden. Love the abundant small round pink flowers!
On May 21, 2013, bariolio from Houston, TX (Zone 9a) wrote:
I got a cutting of this cute little plant from another DG member. Having read the prior reviews, I thought I'd be smart and plant in a pot. It really thrived here in Houston and bloomed loads of little pink balls, with the stems trailing over the side of the pot. THEN, I noticed TONS of tiny new plants coming up everywhere! I'm writing this just to add another caution. If you have a large space that needs filling, this is a pretty plant to do the job. If you don't want it to grow EVERYWHERE in your garden, you might not want to plant it!
On Nov 3, 2012, henryetta69 from Wichita, KS wrote:
I am thrilled with this plant. It is not invasive here in Central Ks. It is like an annual. Starts growing in spring and at the first frost its gone.
On Jan 9, 2010, herbymom from Long Beach, CA wrote:
I garden in Long Beach, California and saw this plant growing on a neighbor's parkway. It was beautiful the way it trailed over the curb. I found it at the local nursery under the simple name of pink clover. I've also seen it as polygonum-pink clover. I planted it on the corners of my parkway last June. the center of the strip is planted with thymes and sedums with some small bellflowers here and there. It's beautiful! Here it is January and that pink clover is still perky as ever. Yes it spreads and seeds but not nearly as quickly as some plants. It's very easy to yank out of areas where you don't want it. I'd much rather spend my time pulling out extra plants rather than coaxing finicky plants.
On Apr 22, 2009, ejanelli from San Francisco, CA wrote:
In a benign climate like ours, this plant is so invasive it will choke out almost anything, and it will not respect any form of boundary because the tiny seeds spread everywhere. I suppose if your purpose were to cover an old asphalt roadway that you didn't want to tear up you could plant a few seeds in the cracks and let this take care of it. It is not easy to get rid of because of the profuse seeding. BEWARE!
P.S.The plant is also identified as Polygonum capitatum by the USDA.
On Jul 4, 2007, macybee from Deer Park, TX (Zone 9a) wrote:
In Deer Park, Tx
This is a perennial groundcover. My girlfriend in same neighborhood has it all over her yard. I'm having a hard time even rooting it. (It's going to work this time)
I think it is very pretty.
On May 16, 2006, jcangemi from Atascadero, CA (Zone 8a) wrote:
I always thought it was pretty, when in other people's landscape. Though uninvited, it self-seeded from flower beds some100 yards or so away and it has now taken over 3 of my large flower beds and I'm AGGRESSIVELY removing it. It has choked out all other plants including Stachys byzantina or Lamb's Ear, a once beautiful creeping wooly thyme, many beautiful clumps of Cerastium tomentosum 'Snow in Summer', a gorgeous sedum ground cover and my annuals are unable to reseed, i.e. lobelia, which readily self-sows. I still think it is pretty and in the right place, a good filler, but I don't have that kind of spot. Be careful w/this one.
On Apr 16, 2006, Joy from Kalama, WA (Zone 8b) wrote:
One of my plant books also gives this the common name of 'Pink bubbles' I've also heard it called 'Pink buttons'.
It makes a nice and interesting ground cover. The more sun it gets the deeper the color on both the foliage and the small button like flowers. And it's pretty drought tolerant.
Here in my zone 8b garden in the Pacific Northwest it dies back completely in the winter and comes back each spring. I'm not having the the same problem with it being so invasive as others are having. Maybe the fact that it goes completely dormant here keeps it from being too aggressive?
On Aug 8, 2003, jkom51 from Oakland, CA (Zone 9b) wrote:
This plant competes on equal footing with oxalis as being aggressive to the point of invasive. In a frost-free zone I would be very careful where this plant is sited. It will literally travel hundreds of feet and pop up where it is least expected, which is not necessarily a virtue! It is very pretty in flower, however, and pulls up fairly easily. Apparently pest-free as well.
On Sep 5, 2002, Weezingreens from Seward, AK (Zone 3b) wrote:
Pink Knotweed self seeds readily where climate permits (zones 8-9). Native to China and the Himalayas, this plant is a member of the buckwheat or dock family. Its foliage is evergreen in milder climates.
On Apr 20, 2001, Zanymuse from Scotia, CA (Zone 9b) wrote:
Very vigorous vining ground cover. Can be invasive. Leaves are deep green with burgandy chevrons. Stems are reddish and the flowers are tiny pink balls.
Persicaria capitata is a prostrate herb.  The leaves are 1–6 cm long, 0.7–3 cm wide with pink to red bands or blotches and short scattered hairs.  The spikes are 5–10 mm long and 5–7 mm in diameter. 
Persicaria capitata has a strong urine-scented odour. [ citation needed ] 
Persicaria capitata is a native of Asia. It has naturalised in parts of Australia  and North America.  Between 2008 and 2013 it has been recorded as an invasive plant in Ireland from the Counties Fermanagh, Kilkenny, Wexford and Mayo. 
Persicaria capitata has been widely used in China in the treatment of various urologic disorders including urinary calculi and urinary tract infections. 
- ^The Plant List, Persicaria capitata (Buch.-Ham. ex D.Don) H.Gross
- ^BSBI List 2007 (xls) . Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26 . Retrieved 2014-10-17 .
- ^ ab
- "Polygonum capitatum". Natural Resources Conservation Service PLANTS Database. USDA . Retrieved 31 January 2016 .
- ^ abFlora of China, Polygonum capitatum Buchanan-Hamilton ex D. Don, 1825. 头花蓼 tou hua liao
- ^Biota of North America Program 2014 county distribution map, Persicaria capitata
- ^ abcd
- "Persicaria capitata". New South Wales Flora Online . Retrieved 2009-07-25 .
- ^Flora of North America, Persicaria capitata
- "T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network - Persicaria capitata (Pink Knotweed)". www.terrain.net.nz . Retrieved 2018-05-23 .
- ^ Devlin, Z. 2017 A new record for the introduced plant Persicaria capitata (Pink-headed Persicaria), from Newport, Co. Mayo (H27).Irish Naturalists' Journal35:116
- ^ Liao SG, Zhang LJ, Sun F, Zhang JJ, Chen AY, Lan YY, Li YJ, Wang AM, He X, Xiong Y, Dong L, Chen XJ, Li YT, Zuo L, Wang YL, "Antibacterial and anti-inflammatory effects of extracts and fractions from Polygonum capitatum." J Ethnopharmacol. 2011 Feb 3 Authors:
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