I pushed the willow cutting into the soft, dark soil in the low back corner of the yard, where the lawn dips down to meet the seasonal drainage ditch. Water sat in my boot prints. The house was a good hundred feet behind me, the septic field even further. That damp, open patch is the best place weeping willow roots can find. It is wet, it is sunny, and it is far from anything the tree could wreck.
Your tree wants a large, open, sunny site near water and far from any building. Smart weeping willow placement comes down to two things. The tree needs steady moisture, and it needs room. Give it both and it thrives for decades. Skimp on either and you fight it the whole way. So your first job is to find a spot that has the space to spare.
The room part is not a guess you can fudge. Willow roots spread out about three times the distance from the trunk to the edge of the canopy. Your tree matures at 30 to 50 ft (9 to 15 m) tall and nearly as wide, so it pushes roots far past its branches. Those roots chase water, and they will find your pipes if you let them get close.
So leave a clear circle of at least 50 ft (15 m) between the trunk and anything you care about. That means pipes, septic lines, foundations, sidewalks, and your neighbor's fence too. Willow roots are shallow and aggressive. They crack concrete and clog drains when a tree sits too close to a structure.
The good news is your tree is easy to please on soil and light. It takes full sun to partial shade, though full sun gives you the fullest canopy and the heaviest curtain of branches. It handles clay, loam, and sand with no fuss. It also copes with a wide pH range from acidic to slightly alkaline, so you rarely need to amend the ground first. Few large trees are this forgiving about what you plant them in.
This is why planting near water suits a willow so well. The banks of a pond, lake, or stream keep the roots wet without you ever lifting a hose. On a big property, a willow draped over the water is the picture most people have in mind when they buy one. The setting feeds your tree and shows it off at the same time. If you have water on your land, plant beside it.
A small suburban yard is the wrong place, full stop. There is no honest way to fit a 50 ft (15 m) root buffer into a quarter-acre lot. People plant one anyway, and five years later their roots are in the sewer line and the canopy is scraping the roof. The tree gets the blame for what was really a siting mistake. Do not put yourself in that spot.
If you love the weeping shape but lack the land, plant the dwarf Salix integra Pendula instead. It tops out around 6 to 8 ft (1.8 to 2.4 m) and works in a large pot or a tight bed near your patio. You get the same cascading look with none of the root drama under your foundation. Pick the tree that fits your space, not the one that fights it. Match the willow to your yard and you both come out ahead.
Read the full article: Weeping Willow Tree: A Complete Guide
