Fallopia japonica Variegata

The Fallopia japonica Variegata is a superb representative of the perennial polygonum tribe, known for their vigor, sometimes uncontrollable exuberance, and extremely easy cultivation. This variety, less invasive than the type, stands out for its red stems adorned with wonderfully and randomly variegated leaves in different shades of green and cream-white, sometimes bordered by a purple filament. Its second asset is its slender clusters of sweetly scented white flowers that bloom throughout the summer. Anchored by wandering and particularly resistant rhizomes, this plant quickly forms a vigorous clump, remarkably ornamental in slightly shaded areas of the garden or in a large planter that it will happily take over on the terrace or balcony.

Japanese knotweed is a perennial plant with trailing and woody rhizomes from the polygonaceae family. It is native to the damp undergrowth of eastern Asia, particularly China, Korea, Japan, and Siberia. Classified in France as an invasive plant, it has abundantly naturalized in Europe, in wet environments near swamps and watercourses. Its rhizomes can reach depths of up to 2m (7ft) in search of moisture and remain dormant for several years before finding favorable conditions for above-ground vegetation development. Invasive in wet soil, it is easier to contain in drier soils.

The 'Variegata' cultivar, like many variegated foliage plants, has a more modest growth and less vigour. This variety forms a large spreading and bushy clump within 3 or 4 years, reaching a height of about 1.20m (4ft). Its lateral growth allows it to cover a minimum of 90cm (35in) on the ground. Coral-coloured shoots, variegated with cream-white, emerge from the ground in spring. They quickly elongate into hollow, reddish stems that resemble thin bamboo canes. Once the maximum height is reached, these stems branch out. They are adorned with broadly ovate-triangular leaves, reaching 10 to 15cm (4 to 6in) in length, arranged alternately on the branches. Their variegation is superb, each leaf is different, combining different shades of green with cream-white. Some are almost entirely white, others heavily speckled with spring green, marbled with almond green, streaked with green and cream etc. The plant continuously produces new leaves until summer. The above-ground stems and leaves of Fallopia japonica 'Variegata' die in winter, with only buds persisting underground and at ground level.

The flowering occurs from June to October if faded inflorescences are removed. It appears at the axils of the leaves, in the form of long branched panicles adorned with numerous tiny 5-petaled white flowers. Highly fragrant, they are a good source of nectar for bees. In France, the seeds of Fallopia japonica are rarely fertile: the plant mainly spreads through its rhizomes, as a tiny fragment is capable of regenerating an entire plant.

Hardy in zone 4 (down to -30°C (-22°F)), loving humid and cool atmospheres, and beautiful near water features, Polygonum japonicum Variegatum withstands dry periods in summer once well established. Almost indestructible, it simply goes dormant, waiting for better days and becomes less invasive. It has its place in light woodland, alongside Solomon's seals, hedge honeysuckle (Lonicera xylosteum), or easy-to-grow ferns like lady fern (Athyrium filix-femina). But it also integrates well into a large border, accompanied by botanical roses, Diervillea splendens, or Physocarpus. It is an easy, beautiful perennial that requires some monitoring when planted in the ground. On the terrace or balcony, provide it with a large planter and avoid neighboring plants that it would quickly smother.