For an overlapping screen or windbreak, plant the trees close enough to overlap after several growing seasons.
Overview. Hybrid poplars are fast-growing trees that can potentially shade a one-story house in three years. Plant your tree as soon as possible after purchasing it. If you can't plant it right away, store it in a cool place such as a garage and water the roots in the meantime.  Overview. Poplar trees can survive winter temperatures that fall down to minus 35 degrees F. These deciduous trees grow 40 to 60 feet tall and spread 35 to 50 feet wide. Poplar trees can grow up to 10 feet a year and are one of the fastest growing shade tree varieties. These trees can survive in clay or sandy soil, and prefer full sun to partial shade exposure. Step 6. Fill the hole halfway with soil and gently firm the soil around the roots of the poplar tree. Check to see if you have the tree standing straight. Finish filling the hole with soil and press the soil down with your feet. Flood the area with water, let it sink in and then water again. The other reason to plant a tree close to your house is to help keep it cool in the summer. This can help you save on your air conditioning costs. Some guidelines for planting trees for energy savings include: 1  Plant large deciduous shade trees on the east, west and southwest sides of the home to shade your house.  Poplar trees make for a great privacy tree or shade tree with its tall dense foliage and ability to be planted reasonably close together. Poplars are also highly sought after commercially for their wood which is often used in furniture and construction. Place the Poplar tree inside and cover with soil. Cover with mulch and allow up to 20 feet between planting – this is if you want a thick foliage. Spread them out further accordingly. Watering: Rainwater should be enough but in times of drought, or heat you may want to add a little extra watering to your usual routine. Lombardy poplars have dense growth that can be sheared in a hedgelike manner. Lombardy poplar (Populus nigra) is a fast-growing tree, often planted in rows for a windbreak. Capable of growing up to 6 feet in one year, Lombardy poplar grows best in well-drained loam, clay or sandy soil with a pH level of 4.5 to 8.5. Spacing. Lombardy poplar (Populus nigra Italica) spreads to a width of 10 to 15 feet. For an overlapping screen or windbreak, plant the trees close enough to overlap after several growing seasons. For a quick screen, plant Lombardy poplars 5 to 8 feet apart. Take into consideration overhead power lines and underground water and sewer lines when planting Lombardy poplar Planting Instructions: Dig a hole twice as wide as the root ball. Place the Poplar tree inside and cover with soil. Cover with mulch and allow up to 20 feet between planting – this is if you want a thick foliage. Spread them out further accordingly. Watering: Rainwater should be enough but in times of drought, or heat you may want to add a little extra watering to your usual routine. Most home foundations are built to withstand encroaching tree roots and won't be damaged by them directly. However, by removing moisture from the soil, some trees can cause severe subsidence (movement of the ground) that can damage your foundation and underground services. Always ensure that you are planting your trees far enough away from your house or other buildings. Tree roots can be destructive to foundations, especially in clay-rich soils. Branches can also pose a hazard if they happen to break from the tree.  Poplar Tree Care. Whether you are planting hybrid poplar trees or one of the popular varieties, you’ll find that poplar tree care is easy in the proper location. Poplars need fertile soil, acidic or neutral, as well as direct sun and sufficient water to keep their roots moist. 
http://www.gardenguides.com/68314-plant-hybrid-poplar.html http://www.gardenguides.com/106334-plant-poplar-tree.html http://www.yourgardensanctuary.com/tree-to-house/ http://www.plantingdirections.com/poplar-tree-planting-directions/ http://homeguides.sfgate.com/planting-spacing-lombardy-poplar-trees-25496.html http://www.plantingdirections.com/poplar-tree-planting-directions/ http://treetime.ca/article.php?artid=29&artcatid=5 http://www.gardeningknowhow.com/ornamental/trees/poplar/growing-poplar-trees.htm
how close can you plant poplar trees