Collection


This unusual plant is a perennial, but is mostly grown as an annual. It is very easy to grow from seed if sown in February to March. It will already flower in May or June of that same year and will continue flowering till September or October, producing many seed berries which contain 50-100 seeds each. This large seed production (and the risk of it becoming a weed) is also known in another plant, Talinum paniculata. When ripe, the berries turn brown and open on the bottom to release the seed, unlike Talinums which explode, scattering the seed over wide areas.

Lopezia can grow in poor soils where it will remain a reasonably small plant. In richer soils, it will grow much larger, up to a meter high. It is native to Mexico, Salvador and Guatemala and belongs to the family Onagraceae. There are seven species known in these countries, all fairly similar in growth and requirements. L. racemosa is commonly known as the mosquito flower because the flowers resemble a mosquito flying at you.

Lopezia racemosa

Lopezia racemosa

Lopezia racemosa 2

Dregeas come from Asia and are evergreen in the wild, but if you keep them in your greenhouse with low winter temperatures, they will lose most of their leaves. They are also known under their synonym Wattakaka sinensis.
It is a climbing plant that will flower every spring with white flowers that have a splash of pink in the centre. They are highly scented, which usually means in these type of plants that they are moth-pollinated. The flowers last for up to a week and resemble hoya flowers. Not surprising as Hoyas and Dregeas are related. Another asclepiad species that has highly scented moth-pollinated flowers is Araujia sericifera, although the flowers on that plants do not resemble Dregea flowers.

Dregea sinensis

Dregea sinensis

As with Hoyas, Dregeas rarely set seed in the greenhouse, but when they do, they form twin-seed horns which will burst open when ripe and can contain up to 50 seeds. The seeds remain viable for up to a year, but it is better to sow them as soon as possible. If you sow them straight away, you will get almost 100% success; if you leave it till 3-6 months, you will get 25-50%; and after a year, you may only get one or two to germinate.
The leaves are heart-shaped and fairly large. It is possible to propagate this plant by cuttings, preferably in the spring. I use cuttings with two nodes, one for the roots and one for the new growth, just as you would do with Hoyas. They can be grown in shade or full sun and will grow outside in the summer. They can have a bit of frost (-2 or 3°C), but it is better to give them some protection.

Before 1994, few Hoya species from Sulawesi were in collections, but in that year a group of Hoya enthousiasts spent three weeks collecting Hoya material on the island. About seventy numbers were collected, but as they were not in flower, some species were collected several times. The plants were brought back to Holland, grown on and brought into flower. One of the species collected was at the time given the number 114, later changed to 8864, and only determined as Hoya pallilimba by Ruurd van Donkelaar and David Kleijn in 2001 (‘Taxonomy and ecology of the Genus Hoya’ in Blumea, 46/3, pp. 457-483). The pallilimba was found by the Ranu River in the Morowali reserve and is a species that grows in association with ants. The ants (genus Tetramorium) take the seed into holes in branches to store as a food supply; the seeds that are not eaten will germinate and grow from the hole. The plant is not solely dependent on the ants; seeds that drop into leaf litter in the fork of branches will also germinate.
Pallilimba is a hanging species that is not very free-flowering. It also has to be reasonably large before it will flower. The plant itself when not in flower is very similar to two other species on the island, Hoya brevialata and Hoya myrmecopa. It is a lot easier to tell them apart, when the plants are in flower. Brevialata has much larger flowers and can be red or white. Myrmecopa has flowers that hang down as buds but which will stand upright when open. Pallilimba flowers are smaller and always reddish in colour.
The plant is reasonably easy in cultivation and can reach a length of 1.50 mtr. It is best grown in a hanging pot to give the stems enough room. It is easily propagated from cuttings; in the summer they will root in about 10-12 weeks. The plant requires higher temperatures than many of the other hoyas, around 20°C minimum.

Hoya pallilimba GPS8864

Hoya pallilimba GPS8864

This very rare Asclepiad and one of only two endemic species from the Dhofar region of Oman, the other being a Dhofaria macleishii (of the Capparaceae family). It is extremely drought tolerant and slow growing. It is an ideal plant for a small collection as it grows very slowly. I have had mine for about 3-4 years now and it has only grown by 4 centimeters in that period. Not suprisingly, it does appreciate warm temperatures, at least 20°C. Despite the fact that it grows in the full sun in the wild, my experience with this plant has shown that it can be grown in the shade without any problem.

It will also flower well, producing up to ten flowers successively in October-November. The flowers are about half a centimeter in diameter and stay open for two or three days. On my plant, they are produced on the new growth at the end of the stem, but in older plants with more growth, they grow in the leaf axils. You can see a picture of a dried specimen here. The few leaves the plant produces at the end of the stem, drop off before the flowers appear. The leaves you see growing in the picture are from a different plant, a Dorstenia foetida.

The plant was named Cibirhiza dhofarensis by Peter Bruyns, but is also known as Cibirhiza dhofarica. Cibirhizas are closely related to Fockea, a well-known species of that genus being Fockea edulis. The tuber of the Cibirhiza is supposed to be edible, but I have not tried it, because I only have one plant and it would be a shame to destroy it.

Cibirhiza dhofarensis

Cibirhiza dhofarensis


Cibirhiza dhofarensis

Cibirhiza dhofarensis

This perennial climber comes originally from South-America, but has now spread over most of the the warmer parts of the world. It is also known as Madeira or Potato vine. Growers in Europe have this as a collector’s plant in their greenhouse, whereas in the warmer parts of the world, they are trying to get rid of it. In some countries is has even become an invasive weed that is difficult to eradicate, because it is almost impossible to get rid of all the small tubercles. When you dig up the plant, the small tubercles that have formed on the stems fall off very easily.
Cutting the stems and leaving the branches lying around does not help to kill the plant, because there is enough energy left in the stems to produce the small tubers. If you really want to get rid off the plant, you need to burn the stems (make sure you gather up all the tubercles that have fallen off) or poison the plant with Glyphosate. You need to do the latter by scraping the bark and putting the poison on the wound so it will be taken into the plant. A bit harsh, but it is the only way unless you happen to live in a country where the temperatures fall below zero, because they cannot take any frost.
Anredera can grow to up to 9 metres long and has bright green heart-shaped leaves. In the autumn, it produces large numbers of small fragrant flowers in racemes. It can grow in semi-shade or full sun and can take a lot of drought. It is propagated mostly by tubercles, rarely by seed. Because it is such a rampant grower, it can be cut back almost to the tuber and it will come back and flower the following year – an ideal beginners plant.

Anredera cordifolia

Anredera cordifolia


 
Anredera cordifolia raceme

Anredera cordifolia raceme


 
Anredera cordifolia tubercle

Anredera cordifolia tubercle

A good plant for cactus collectors, because in the winter it can take low temperatures (even a bit of frost) if kept dry. It comes from the Eastern Cape in South Africa and the tuber can grow to a height of 25-30 cm. The branches that grow on top of the tuber can, if they get too large, be cut back. The flowers develop all over the branches, so you do not lose them if you cut the top bits of the branches off. The flowers are similar in shape to those of Adenium obesum, but smaller. The pollinator is probably a moth as the depth of the flower excludes other pollinating insects. When pollinated successfully, twin seed horns will appear which grow to a length of about 5 cm, containing up to 30-40 seeds. The seed has a parachute on the end enabling it to be carried away to a new area to grow. You can tell the difference between an Adenium seed and a Pachypodium seed, because the latter has just one parachute, while Adeniums have two. It is important to remember that the seed from both these species must be sown fairly quickly after collection, because they have a short ‘shelf-life’. It can be kept for a maximum of one year, but the germination will only be about 10%, if you’re lucky. The fresher the seed, the better the germination, possibly up to 100% if sown the first few days after collection.
Pachypodium bispinosum is virtually identical to Pachypodium succulentum when not in flower. To tell them apart, you need to see the flowers; the ones from the succulentum are flatter. In the wild, their localities overlap a little bit, but there is hardly any cross-pollination, probably because the pollination needs different insects.

Pachypodium bispinosum caudex

Pachypodium bispinosum caudex


Pachypodium bispinosum flower

Pachypodium bispinosum flower

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

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