Biophytum sensitivum comes from Africa and India and grows to about 20cm high in a rosette which gives the impression of a small palm tree. As with other similar plants, such as the Maranta, the leaves shut at night. It does not require special soil, but keep it moist at all times. Most people know the plant Mimosa pudica, the sensitive plant, but another plant, less well-known, is the Biophytum sensitivum which also has similar properties of being able to close up its leaves for protection. However, in this case, the leaves are folded downwards whereas on the Mimosa they are folded upwards. The only pests that may attack the plant are fungus gnats whose larvae gnaw away at the base of the stem. In the wild, other plant-eating insects will try to feed on this plant, but to combat this, the plant folds its leaves and the insect falls off. As the leaves also contain the poison oxalate, it is not clear why the plant has this additional leaf-folding protection.

The Biophytum was first described in 1753 as Oxalis sensitivum, possibly because Oxalis and Biophytum shoot out their seeds in similar ways. This is a sure way of reproducing itself as at least some of seeds fall onto good soil and will germinate quite quickly. Watch out for this phenomenon in your greenhouse, as you may end up with Biophytums all over the place. This only happens if you keep the temperatures above 16° C. at all times, as they do not like cold. It is an ideal plant for terrariums with their high humidity and low light, because that imitates their natural conditions. It is an annual, but it will live for more than one year. Make certain to save some seed while it is available, because the plant may suddenly die and you would be left with nothing. The flowers do not have to be cross-polinated, so one plant is enough to produce seed. When the seedpod is ripe, it will open up into a star-like structure in which you can clearly see the seeds. It opens up in the morning and by the afternoon, all the seeds have sprung, so make sure to collect them in time.

Biophytum sensitivum

Biophytum sensitivum


Biophytum sensitivum seed pod

Biophytum sensitivum seed pod

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This unusual plant is a climbing species of the Acanthaceae family. You are probably more familiar with its cousin, Black-eyed Susan, Thunbergia alata. The mysorensis is a tropical species that comes from southern India where it is used as hedging. It can grow very large, 10-15 metres is quite normal. The plant is very striking with its red and yellow slipper-like flowers which are about 5cm in length. They hang from long pendants with up to ten flowers. The individual flower can last up to a week.
The species is occasionally seen in cultivation and requires a reasonable amount of room. It is propagated by seed and by cuttings. Cuttings need a high temperature to root, ±22-25°C and a high humidity. I have never had seed on my plant, so I do not know what conditions it needs to germinate, but as it is a tropical species, a high temperature is likely. Most cuttings will root in about a month, but some take longer. If possible, plant it out in the greenhouse or conservatory, rather than keeping it in a pot, as it will do much better then. I grow it in a shaded greenhouse, but whether it needs more sun to flower, I do not know yet.

Thunbergia mysorensis

Thunbergia mysorensis

This rare epiphytic species comes from India (Tamil Nadu and Kerala) and is very easy to grow. It can stand a lot of drought and starts to regrow when the monsoon rains occur. It flowers in the autumn in western Europe, but may do so at other times in other parts of the world. If kept watered, it will stay in leaf all the year round, but will not flower all the year round. The flowers are very similar to Impatiens niamniamensis and Impatiens keillii.

It roots very easily from cuttings and can be grown either in a pot or on, for instance, a coco peat block. Keep a minimum of 10°C in the winter and reduce watering to avoid rot.

 

Impatiens parasitica

Impatiens parasitica

This perennial species comes from Sri Lanka and India, specifically from the western Ghats of Tamil Nadu, and is one of the late flowering sorts. It is flowering in my greenhouse at the moment and the flowers are white with splashes of red and between 5 and 7 cm in size. It requires warmth (15-20°C) to do well; it can be kept at 10°C but will not grow or flower so well in cooler conditions. When the temperatures are right and it is kept in a shady place, it can grow into a real bush of up to one or one and a half metres in height. It needs to be cross-pollinated to obtain seed which I have been doing this year and to catch the seed I have used empty teabags which works very well. Perhaps I will get enough seed to be able to offer it on the webshop next year.

 

Impatiens grandis

Impatiens grandis

This species comes from Tamil Nadu in India. It is a low-growing species with bright green leaves and the flowers are fairly large. It is still rare in cultivation, but is an easy species to grow and will flower after a year from cuttings. Conditions: minimum temperature 10° C., shade, moist.

Impatiens cordata