Warning
Purple Loosestrife (Lythrum Salicaria Rosy Gem) This staggering flower is considered a invasive plant in the USA and make sure it isn't in your country. If not contained and properly cared for these flowers will invade wetlands and outcompete native species, which takes away food and habitat for insects and animals. It can also hinder a wetlands ability to properly filter water. 

Description
Purple Loosestrife (Lythrum Salicaria Rosy Gem) - This attractive perennial produces a showy display of carmine-colored flower spikes throughout much of the summer. It was introduced to the United States and Canada as an ornamental for wetlands in the 1800s. The Purple Loosestrife flower inhabits reed swamps, margins of lakes and slow-flowing rivers, ditches and marshes. It is an aggressive flower and has spread westward and can be found in all states except for Florida. Please check with your state to make sure Purple Loosestrife is ok to plant in your state. There are many states that prohibit planting Purple Loosestrife. It is still promoted by some horticulturists for its beauty as a landscape plant, and by beekeepers for its nectar-producing capability.

Sowing:
Season: Perennial
Sowing: May - June
Height: 80–120cm ()
Blooms Season: July - September
Environment: Full sun, Partial shade
Germination Time: 15-30 days
Temperature: 18-22°C (65-70°F)
Plant Watering: Medium Well-drained

Sowing seeds in the seed-bed. Transplant to the permanent place in August – September on approx. 40-50 cm apart. Easily grown in organically rich, fertile and moist soils.