Houttuynia palustris, or marsh ottonia, is a lively water-based carpeting plant native to Japan and China. It is also called a water broom. It forms dense tufts of reddish stems covered with heart-shaped, bluish-green leaves; in late spring or early summer it produces long inflorescences consisting of large white bracts with an ear of white flowers in the center; it has rapid and vigorous development, spreading by means of fleshy stolons. In autumn the aerial part of the leaf dries completely, and then reappears in summer. It reaches a height of 25-30 centimeters. H. cordata Variegata has large leaves with cream variegation; H. cordata Camaleon has cream, light green and red variegations; these two varieties have slower growth and more compact growth than the species.
Houttuynia palustris develops well both in the sun and in partial shade; in the sun, the leaves of the water broom take on a more decorative color, especially those of the variegated species, while sheltered from the direct rays of the sun the marsh brass plant has a more vigorous growth.
These aquatic plants particularly love the shores of lakes and streams, they must be buried where the water reaches 7-10 centimeters in depth. The temperature of the water in which the plants of this variety are grown should not exceed 25 ° C to prevent the specimens from showing signs of suffering.
Naturally, being an aquatic variety, it does not tolerate even brief periods of drought since the land in which it is cultivated must always be rich in water.
The Houttuynia palustris needs rich, loose, well-drained soil; to prepare the ideal substrate, use universal soil mixed with sand and perlite.
Swamp ottonia plants can also be grown in pots, taking care, of course, to check that the soil can maintain the right humidity and does not dry out. The water in the container must be changed at least every 15 days.
If it is noted that the water broom specimens have a stunted and not very vigorous growth it could be that the water in which they are placed present in its interior little nourishment and mineral salts; in these cases it is possible to add liquid nutrients to the water, which will help plant growth.
The multiplication of this genus of plants to obtain new specimens takes place by cuttings, to be rooted in a mixture of sand and peat in equal parts so that the new shoots have time to develop and acquire the necessary strength that will allow them to grow in a luxuriant way; in spring it is possible to divide the most voluminous tufts, immediately placing them in the place where they intend to cultivate new plants.
Marsh Ottonia, Water Broom - Houttuynia palustris: Pests and diseases
This plant turns out to be rather rustic and vigorous; for this reason, it is almost never attacked by pests and diseases. It is therefore not necessary to proceed with preventive interventions based on insecticide products, given that these plants can provide for their protection independently.