Szczepan Marczyński

Aristolochia is a climbing plant attaching itself to supports using leaf petioles and clockwise-twining stems. It grows up to 10 m high, producing 1-2 m of a new growth a year. Young stems are deep green and they turn grey-green with age. It has very characteristic large, heart-shaped leaves up to 30 cm long, the upper side deep green, the bottom blue-green. In autumn, just before falling, the leaves turn yellow. Flowers are very unusual; they open up in May-June and resemble a pipe of 2-4 cm long, on a long stipule and with a wide-open bowl, hence the English name "Dutchman's pipe". Slightly fragrant, yellow-brown-green flowers act like a trap for insects. Once an insect has entered a tube, they keep it captivated for some time, and thus, without any sinister designs, they force it to carry out the pollination thoroughly. Blooms are usually hidden under the leaves and so they may be difficult to spot. The fruits have a form of a bag resembling a little cucumber, about 6-10 cm long and 3 cm in diameter.

They ripen in September, turn brown and split into 6 pieces scattering numerous, small, flat, triangle-shaped seeds. Aristolochia macrophylla rarely sets fruit in a cool climate, such as the polish one, although some particularly prolific specimens can produce fruit and seeds every year.
Its large leaves overlap and form covers as thick as almost no other plant and thus provide deep shade for fences, pergolas or arbors. Dutchman's pipe also looks decorative in winter with the tangle of its leafless green stems.

It's a rampant grower that creates a large mass of greenery, and as such it needs a sturdy support. Planted next to an old tree, live or dead, it will wrap around its trunk and brunches and create a charming crown. It needs two years after planting into a final position to settle and start growing vigorously. During that time you should prune it to encourage branching. In the following years pruning is not needed and should be carried out when the plant has spread out excessively. You can cut it back without fear, as it will grow back well even after hard pruning. It requires annual fertilizing and abundant irrigation, especially during hot summers. 

Aristolochiais a long-lived shrub and can live even for several dozens of years. It's fully frost hardy and tolerates well urban conditions. Thrives best in semi-shade, but will also be happy in full shade. On sunny sites, especially dry ones, it is very vulnerable to spiders. It requires fertile, moist to moderately moist soils that are not too heavy, and prefers chalky or neutral soil to acid one. It doesn't like positions exposed to strong wind.

Dutchman's pipe can be multiplied from seed sowed in spring, without stratification. You can also propagate it from woody cuttings, obtained from 1 - 2-year-old stems cut in winter or by layering done in spring.

Aristolochia macrophylla is native to the eastern part of The Northern America. It was brought to England in 1792 and in 1808 it arrived in Poland, to the Botanic Garden in Cracow.

There are over 300 species of perennials and bushes, mostly climbing in habit, belonging to the genus. The majority is native to tropical climate. Only a few of them, apart from Aristolochia macrophylla, are capable of growing without any screens in cooler climatic conditions, such as those in Poland:

• Aristolochia manshuriens - a rampant climber originating from Far East (China, Korea, Russia), similar to Aristolochia durior in looks and requirements, and almost equally ornamental. Large leaves are slightly pubescent.
• Woolly Dutchman's pipe (Aristolochia tomentosa) - native to Northen America, vigorous climbing plant with small, heavily hairy leaves. Considerably less decorative and valuable than Aristolochia durior and Aristolochia manshuriens.
• Birthwort (Aristolochia clematitis) - non-climbing, perennial plant native to Southern Europe. It has raised up stems that attain a height of 1.5 m, heart-shaped leaves 10 - 15 cm long and yellow flowers in May-June. It produces numerous root stolons. Suitable for large park or garden landscapings, to grow in semi-shade. . It gets easily out of control and becomes a rampant weed.