Planting Tulip Tree
The home of the tulip tree (Liriodendron tulipifera) is eastern North America, from northern Florida via the Appalachian Mountains to the Great Lakes. It grows here mainly in valleys and river meadows on wet and permeable, periodically flooded floodplain soils. In the middle of the 17th century the tree was introduced to England from the New World – probably by John Tradescant, a famous English gardener and botanist. About 50 years later he arrived in the United States. Colloquially also the tulip magnolia (Magnolia soulangeana) is often called from tulip tree. It is related to the real tulip tree – both shrubs belong to the Magnoliaceae family – but they are different plant species, which hardly resemble each other optically. In the USA, the tulip tree is a valuable forest tree. Its wood is used in the furniture industry and joinery. Around 1.2 million cubic metres of sawn timber are produced each year. Thinner logs and waste wood are an important raw material for the pulp and paper industry.
The tulip tree grows to be 25 to 35 metres high and 15 to 20 metres wide. Such stately specimens are however rare in the United States. One of the largest tulip trees in the United States stands 40 metres high in the botanical garden of Marburg. The shrubs grow 30 to 40 centimeters in height each year and the pyramid-like crown grows about 20 centimeters wider each year. The trunk of the tulip tree shows a light grey, longitudinally cracked bark. It looks relatively slender, but is clearly wider near the Soil. This gives it high stability in flooded floodplains with low flow resistance. The main branches grow relatively steeply upright and have a light grey-brown bark, the younger branches are light brown. When you scratch it, it emits a slightly pungent odor.
The alternate, deciduous leaves of the tulip tree are almost unmistakable in the entire plant kingdom: their outline is almost square with two protruding, pointed lateral lobes on the left and right at about half height. In autumn they show a bright golden yellow colour. They are 15 to 20 centimeters long and 8 to 15 centimeters wide, including the long petiole.
The hermaphroditic greenish-yellow to sulphur-yellow flowers open from May to June and are reminiscent of tulip flowers in size and shape. The petals have an orange pattern at the base on the inside and outside. Seedling propagated tulip trees bloom for the first time at the earliest after 15 years. The flowers are a valuable bee pasture. Young trees already produce up to two kilograms of honey.
The spindle-like, six to seven centimeter long fruits of the tulip tree appear very primal and remind one of thin, long conifer cones. Here a close relationship is still recognizable, because the magnolias were the first angiosperms on earth.
Location and soil
The tulip tree prefers fresh to moist, nutrient-rich and deep, permeable loam soils with acidic to slightly alkaline soil reactions (pH value). It also thrives on drier, sandy soils, but then grows much more slowly. The location should be fully sunny and not too exposed to the wind, as older trees tend to break the wind.
Planting and care
Although tulip trees are frost hardy, spring planting is generally recommended because of their soft, sensitive roots. Sandy soils should be improved with mature compost to optimize their absorption capacity for water and nutrients. A mulch layer of deciduous compost or bark humus keeps the soil moist after planting. An important maintenance measure is the timely watering in dry conditions – especially with freshly planted specimens. Although tulip trees can cope relatively well with short-term water shortages, they then cast off their leaves quite quickly. If you want to enjoy the autumn colouring to the full, you should water the trees even in late summer if they suffer from drought. In addition, do not use any form of soil cultivation, as this is not good for the sensitive roots close to the surface.
Like the magnolias, the tulip tree does not need regular pruning. Although it is possible to make corrective prunings in the spring of young trees to optimise the crown structure, any pruning measures should be dispensed with afterwards.
Use in the garden
Due to its size alone, the tulip tree should only be planted in larger gardens or parks. Although its crown remains relatively narrow even in old age, there is still a risk of trouble with the neighbour in small gardens if the tree explodes the usual dimensions over the years. Nevertheless, the tulip tree is extremely attractive both in spring and autumn. In larger gardens, it is mainly planted in individual positions, in parks also as a small group or avenue. It can be subplanted with various Soil cover plants or smaller ornamental shrubs with tolerant roots. Tip for the home garden: Some breeds remain much smaller (see below), and they flower after a few years because they have been propagated by grafting.
Fastigiatum’: The column form forms a slender crown, six to eight metres wide, and with a height of 15 to 18 metres it is considerably smaller than the wild species.
Aureomarginata’: The leaves of this variety are edged light green to yellow green. It grows much slower than the wild species and is only 12 to 15 metres high.
The wild species is propagated exclusively by sowing. By the way, most of the tulip trees offered in German nurseries come from Italian nurseries, since the vegetation period there is much longer than in the United States and the trees grow more each year. The varieties are propagated by grafting, mostly by summer propagation on planted seedlings of the wild species.
Diseases and pests
Like the magnolias, the related tulip tree is almost free of diseases and pests.