Hemlocks are among the most cherished of conifers for their graceful growth habit and fine-textured, evergreen foliage. Worldwide, there are only 10 species of hemlock, according to Michigan State University. One cultivar, Tsuga canadensis sargentii, or Sargent's weeping hemlock, is particularly striking, with pendulous, weeping branches covered with delicate foliage like gray-green mist. Caring for a weeping hemlock means planting and staking it properly and watching for problems common to this plant.
Select a planting site for weeping hemlock that has shelter from other trees. It will not do well in open, exposed areas. Soil should be moist, free of rocks and debris, deep and well-drained.
Dig a hole with a shovel twice the width of the weeping hemlock's root ball but no deeper. Set the tree in the hole and check to see that the root crown is an inch or two above the soil line. Backfill with soil, pressing it firmly around the roots to close air spaces. Pour a bucket of water over the root zone after planting to reduce transplant shock.
Stake the weeping hemlock to support its pendulous branches when the tree is young. Pound a tree stake 6 inches into firm ground and secure it to the trunk with plant ties. Leave enough slack in the line and the loop around the trunk to allow the tree to flex a little with the wind, and for its trunk to expand. Remove the stakes after a year or two, or when the trunk's diameter can properly support the canopy.
Spread a 3- to 4-inch layer of mulch in a ring over the root zone of weeping hemlock, beginning 6 inches from the trunk. Mulch will suppress weeds, hold moisture and help regulate soil temperature. Rake out and replace mulch annually to prevent it from piling up.
Prune only dead, diseased or storm damaged wood from weeping hemlock. It looks best when its shape is not controlled but allowed to flow freely. Too much pruning increases the chances of disease or insect infestation through pruning wounds.