Linden Tree Propagation Methods
The linden tree is a large deciduous tree, known in Britain as the lime tree. It is also known in North America as the Basswood tree. It is popular due to its rather attractive dark green leaves, which are later accompanied by yellow flowers. It typically grows to about 40 feet tall, although there are a large number of variations on this size due to the linden tree’s tendency to hybridize very quickly.
Growing a Linden Tree from Seed
Seeds are accepted as the best way to grow a linden tree, although they can be very frustrating due to their low germination rates. For a large number of seeds, there is only a small percentage which actually grows into seedlings. This means that gardeners buying linden tree seeds have to spend a lot of money in order to ensure that a few viable candidates survive.
In order to ensure germination of seeds, they should be planted as soon after ripening as is possible. Older seeds can develop a harder coat, and require manual ‘grazing’ of the seed. Experts sometimes soak older seeds in sulfuric acid, while amateurs prefer the traditional methods of scoring the seeds with a knife or trowel edge.
Once the seeds have been scored or dipped in acid, it is a good idea to keep them in a moist environment until spring. Peat moss or damp sponges/cloths are ideal for this. They can be stratified after 4 months, until germination in the springtime.
Grafting a Linden Tree
An alternative to growing the difficult seeds is to perform a ‘grafting’ of a cutting. Linden tree cuttings have to be grafted onto a root in order for the plant to remain alive long enough for the cutting to develop its own roots. This practice is known as nurse root grafting. A root is cut horizontally, and a split cut across, around 3 inches in depth. The cutting is them eased into this split, so that the deepest parts of the two plants are together. The two portions of the graft are tied together, and the cut covered in grafting wax so that the plant is actually attached to the root and able to draw water from it. This is then planted under the soil, until the nursling self-roots. At this point, the original root can be removed by the gardener, or left to die off.
An alternative to this nurse root grafting is known as ‘bud grafting.' A small piece of cutting, containing only a solitary bud, is used. Peeling back some bark on the root being grafted, the cutting is then squeezed into this gap and the entire thing tied tightly together. The bud and cutting should then grow and develop roots of their own. Care should be taken when using this technique in order to ensure that neither bud nor cutting is damaged during handling.
Once the cutting has grown to a significant height, it can be removed from the soil where it was originally placed and moved to its intended home.