Useful plants of the world

Pepper, tea, coffee, cocoa, rooibos tea, capers, sugar cane, bananas, pineapple, peanuts, allspice, cinnamon and many other exotic crops from around the world can be found in our greenhouses and outdoors. It is one of the largest collections in Germany.


The queen of spices, vanilla (Vanilla planifolia) is the second most expensive spice after saffron. It is the only orchid that is not cultivated for its beautiful yellowish-green flower. It is native to Mexico and Central America.

Today it is mainly grown in Madagascar. It has to be pollinated by hand there - as in our greenhouses - because natural pollinators do not occur in Madagascar. This is what makes vanilla so expensive. The fruits, which can be up to 30 cm long, are traded after fermentation.

Vanilla (Vanilla planifolia) © T. Niemz

Macadamia nut

Blooming Macadamia integrifolia with ripe and burst fruit © W. Lobin / Universität Bonn

And the next queen: the macadamia nut (Macadamia integrifolia). Macadamia nuts are very tasty. The cultivation is difficult and the processing is costly, no wonder they are very expensive. For this reason the macadamia nut is also called the "queen of nuts". It is native to the Australian rainforests. The Aborigines have loved these nuts from time immemorial. Our macadamia trees are outside in the summer.


Pomegrenate (Punica granatum) © I. Fuchs

The pomegranate (Punica granatum) has been cultivated for over three thousand years. It is already mentioned in the Old Testament and in the Koran. Its name derives from Latin and means "provided with many seeds". It is native to the area of Iran, Afghanistan and the Near East. Nowadays it grows in our Garden of Useful Plants too. For several years now, a pomegranate tree has been growing here in the open and bearing fruits.

Eine Wissenschaftlerin und ein Wissenschaftler arbeiten hinter einer Glasfassade und mischen Chemikalien mit Großgeräten.
Calamansi (Citrus x microcarpa) © C. Löhne / Universität Bonn

Citrus fruits

Citrus fruits (Citrus spp.) are native to Southeast Asia, one species is found in northern China and one in eastern Australia. They grow as shrubs or trees, the latter reaching up to 25 m high. The blooms are white and many smell intensely aromatic. Especially the fruits contain many essential oils.

Due to the essential oils people started cultivating various species very early on. As early as 2000 BC, Chinese sources mention kumquats and mandarins. Around 300 AD, the Romans knew of citron lemons, bitter oranges and lemons. Today, most species are in cultivation. Hundreds of varieties have been bred.

In the Garden of Useful Plants we currently cultivate more than 40 species and varieties of tangerines, oranges, grapefruits, limes, lemons and citrons.


Citron "Buddha's Hand" (Citrus medica cv. 'Digitata') © W. Lobin / Universität Bonn

The citron "Buddha's Hand" (Citrus medica cv. digitata) is native to Southeast Asia. It usually has more than five fingers, and no two fruits are alike. It has been used since time immemorial in China and Japan as an air freshener or perfume. It is also very good for marmelades, liqueurs and syrups.


Lemon (Citrus limon) © W. Lobin / Universität Bonn

The lemon (Citrus limon) is a cross between bitter orange (Citrus × aurantium) and citron (Citrus medica). It is said that lemons were already cultivated around 1000 AD in the Mediterranean region and in China. In the Baroque period, lemons were considered a symbol of immortality. The beautiful orangeries were built for the lemon plants.

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