Populus is a genus of deciduous flowering plant. They are native to most of the Northern Hemisphere. A “hybrid” plant is produced when pollen of one species is used to fertilize flowers of another species. Therefore, a Hybrid Poplar is a Populus tree resulting from the combining, either naturally or artificially, of various Poplar species. Hybrid Poplars are among the fastest-growing trees in North America. Hybrid Poplars are not usually desirable in many landscapes but can be of major importance under certain forestry conditions. Logs from the Populus are a common environment for Shiitake mushrooms to reside and were once used in Italy as a popular art medium; the most famous example of which is the canvas used to paint the Mona Lisa.
Seasonal information: Be sure to plant your Hybrid Poplar tree at least six weeks before your first frost. This will give the tree a chance to adjust to its new environment. If you are experiencing extreme heat, place your potted tree in a well-shaded area, such as a garage, or plant it in a well-shaded area in your lawn. Once older, your tree will be able to handle these temperatures. Typically, the Hybrid Poplar do not experience much growth during times of extreme temperatures.
Location: Hybrid Poplars grow well in various soils. They grow much better in more fertile soils than in poor soils. Areas of high pH will reduce their growth and may kill them. A soil test is cheap insurance. A pH over 8.0 is dangerous. Hybrid Poplars achieve best growth in deep, fertile, alluvial soils that have adequate moisture with capacity to hold it. Agricultural lands not currently suited or used for cultivated crops, such as in grass for hay or pasture, are fine. Quality cropland also can be used.
Planting instructions: Your planting site should be made of loose, quality soil. Dig your hole two times the width and depth of the root system of the plant you are working with. This will give the roots plenty of room to grow. When refilling the hole with soil, be sure to completely cover your roots with soil so that there are no air pockets underground. If pockets of air come in contact with your roots, they will dry out quickly.
Watering: Hybrid Poplars should be planted in moist soil and be irrigated properly, especially in the first year of planting, to help the development of a good root system. Sites that maintain good moisture throughout the year are fine to minimize the need for further irrigation beyond year one. They can handle short-term flooding if the water keeps moving and the water table drops below the soil surface before the trees leaf out in the spring. Best would be if the water table is 1.5 to 3 feet below soil surface. For ample and continued growth, soil moisture should be monitored, and Hybrid Poplars should not be stressed.
Fertilization: In fertile soils, including some old pastures, the nitrogen released from organic matter within the soil can be sufficient to carry the trees for several years without the need for added fertilizer. A rate of 50 to 150 lbs of nitrogen per acre per year is the general rate applied if needed. This again can be found out when you take your initial soil test to see if the land is suitable. Treat the Hybrid Poplars as you would a regular crop for best results.
Weed Control: If weeds and grasses are not adequately controlled, they will cause Hybrid Poplars to grow slowly and may kill them. This is especially true in the first year or two of growth. Herbicides can be used before planting and after. Check with your local supplier. They can also be cultivated in areas accessible to eliminate or minimize herbicide use. Depth should be kept to a minimum of 3 to 4 inches to protect root growth. As trees get older and shading occurs, weed growth is less.
Pests and Disease: The best defense is a healthy tree. Hybrid Poplar trees are very hardy. Good soil, proper feeding, and keeping the tree from getting too much water are key to its prosperity. If worms bite holes in the leaves you can sprinkle Seven Dust on them. These little bites do not affect the tree since it is growing at such a fast rate and is putting on so many new leaves.
Pruning: Prune the trees during the dormant season, which is winter, because the leaves have fallen off and you can best see the shape of the tree. In addition, new sprouts have not surfaced, so you are causing less damage than if you prune during the growing season. Look for diseased, dead, or damaged limbs as the tree matures. Make a small cut into them with the pruning shears, and if there is no green flesh inside, remove them. Cut at the point where they meet healthy limbs. Make sure all branches are facing the sky, so they are open to sunlight and air. Prune any Hybrid Poplar branches that are facing down toward the ground.