Hoya pallilimba

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

 

Dendrosicyos socotrana

Most people know of the tomato tree, but there is also a plant called the cucumber tree, which is endemic on the island of Socotra which belongs to Yemen, but lies closer to Somalia than to the Arabian Peninsula. It was discovered by Sir Isaac Bayley Balfour in 1882. It is extremely rare in cultivation with very few nurseries offering it for sale. It is a monotypic genus in the family of Cucurbitaceae and the only tree in the family, the rest being climbers. The temperature on the island is always more than 20°C, also at night, therefore this plant requires a high temperature in the greenhouse to grow. It can survive at lower temperatures, 15°C minimum, but it won’t grow well. It also prefers bright light, but will tolerate some shade. It can take a lot more water in the growing season, but be careful not to overwater it in the winter. If you keep the winter temperatures high enough (20°C or more), the plant will keep its green leaves, but will drop most of them them when kept cool (15°C). It can grow to a height of six metres, producing a whitish bark which contrast with the green leaves.
The flowers are produced after about five years from seed; the flowers are yellow as with most Cucurbitaceae and unisexual and monoecious (growing on the same plant). The fruit is orange, but fairly small and mainly eaten by the sheep and goats on the island. Traditionally, it is also used for medicine.
Propagation is mainly from seed, but a few exeperiments that I have done prove that it is possible to propagate the plant from cuttings. One needs tip-cuttings put it a high humidity propagation unit, so that the cuttings will not dry out. I do not yet know, however, if the plants will form a caudex if grown from cuttings. Experiments are ongoing.

For a more complete description of this interesting plant, see here.

Dendrosicyos socotrana

 

 

Anredera cordifolia

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 raceme

 

Anredera cordifolia tubercle

 

Hoya sp. Sulawesi GPS 8860

This Sulawesian species was collected in 1994 between Tentena and Kolonodale. It is very similar to H. paulshirleyi GPS 8845 and to GPS 8865 and GPS 8870, but the flowers are much lighter. It was growing high up in a fairly large tree which made it very difficult to collect. The only way we could get at it, was to try and knock off a few pieces with a branch. It was one of the first plants we collected that flowered in cultivation and it flowers freely and at a young age. Without flowers, this species and GPS 8845 are impossible to tell apart.
It is a very easy plant to propagate by cuttings, unlike the GPS 8845, and will root in about 6-8 weeks. The plant can take a reasonable amount of sun and the leaves will turn reddish if kept in the sun giving a nice effect; they will stay green if kept in the shade. It is a sort that requires warmth to do well, 20°C and over. It can also take a lot of dryness before it dies. So far, I have not seen any seedpods on this species, despite the fact that there are lots of moths in the greenhouse that should have done the trick.

 

Hoya sp. Sulawesi GPS 8860

 

 

Hoya lacunosa

This is a very popular plant in cultivation, because it is very easy to grow and flowers regularly throughout the year with cream-coloured flowers. The flowers are highly scented to attract moths for pollination. It is a suitable plant for hanging baskets where it will grow to 1-2 metres. It can also be grown on a trellis, but it has to be fastened up. It can best be grown in half shade, but it will tolerate some sun. Lacunosa has many variations in leaves and flowers and hence a lot of cultivar names are used for the same species.
The plant originally comes from Java, Malaysia and Thailand and therefore likes a lot of warmth (at least 20°C) to do well. It does well in the ordinary living room as long as you keep it well-watered. It is very easy to propagate from cuttings and also by seed as long as moths have access to the plant.

Hoya lacunosa

 

Impatiens niamniamensis

Impatiens niamniamensisis is a tropical species from the Democratic Republic of Congo and is a very easy plant to grow. It can reach a height of about 2 metres and will spread outwards if you let it. It is easy to propagate by tip-cuttings; it will root in about 4-6 weeks by a temperature of about 20°C. The flowerbuds do not need to be removed from the cuttings, because this has no effect on the rooting.

It likes a minimum temperature of 10°C and will carry on flowering throughout the winter. The red and yellow flowers are mainly produced in the top of the plant, but also along the leafless stem. It is not fussy as regards soil, but prefers a moist soil that does not dry out too quickly.
Another common sort is the type with pink and green flowers which has the same growth habits and requires similar conditions. They are relatively pest-free, but watch out for scale and spint.

 

Impatiens niamniamensis

Impatiens niamniamensis pink and green

 

Jatropha podagrica

Jatropha podagrica is native in South-America where it can grow into a large flowering shrub. It is now found in Africa and Asia as well, because this plant is propagated in nurseries and due to the springing of the seed when ripe the plant has escaped from the nurseries into the wild where it can establish itself. Due to the poisonous nature of the sap, there are few creatures that will attack it. Jatrophas belong to the Euphorbiaceae which can be seen by the seedpod that is divided into three sections, each containing one seed.
It is a plant that requires warmth; it will die if the temperature drops to 5°C for a prolonged period. The ideal temperature is at least 15°C. The plant is very easy to cultivate as long as the temperature is high enough, not requiring a specific type of soil; it can be grown in the full sun or above the central heating with little water. It can remain in this position all the year round, not requiring a colder period in winter. There is now a yellow form available besides the more usual orange. The yellow one will now come back true from seed which it did not do until a few years ago. If you cross the yellow with the orange, however, the orange will dominate and you could lose the yellow altogether.

Jatropha podagrica orange

Jatropha podagrica yellow

 

Plectranthus ernstii

Plectranthus is a member of the Coleus family; a few have a caudex, such as Plectranthus ernstii which comes from South-Africa and was discovered in 1982 by Ernst van Jaarsveld. There are about 350 species of Plectranthus coming from Madagacar, South-Africa, Indonesia and India, so roughly the countries around the Indian Ocean. They are very easy plants to grow and can take a wide varieties of temperatures; some are even hardy. The ernestii, however, is not, but can take low temperatures as long as they do not drop below 0°C.
The ernestii is very easy to propagate by cuttings. It does produces seed, one seed per flower, but as it is so easy to propagate by cuttings, I have not tried to sow them. Cuttings will always produce a tuber which will, with age, thicken up. Depending on the conditions the plant is grown in, the leaves will either be large or small. Cooler temperatures will result in a more compact plant with smaller leaves. It can be grown in full sun or shade.

Plectranthus ernstii

 

Rhipsalis elliptica

This species comes from Brazil and it is classed as a tropical/subtropical plant, but it can take low temperatures, down to 5°C, which has surprised me. It is also a plant that will flower in the winter; the pictures below were taken early February. It produces masses of white flowers with a red centre and they last a few days. Unlike some rhipsalis, it produces few berries. Perhaps it needs to be hand-pollinated as perhaps there are not enough insects in the greenhouse in the winter.
It is very easy to propagate by cuttings which need to be left for about a week to dry before being put in the soil or rooting medium. As you can see from the picture, it will grow into a fairly large plant, so give it some space. I grow it in shade and it does very well there; maybe it can take more sun, but I have not tried that yet.

Rhipsalis elliptica

Rhipsalis elliptica detail

 

Dischidia nummularia

There are two variations of Dischidia nummularia; one a plain green one, the other with variegated leaves. The green form flowers a lot easier with small white flowers. Dischidias are very closely related to Hoyas, so much so, that a number of species cannot be told apart until they flower. Dischidia nummularia variegata is a good example; it was a few year before it flowered and I could work out what it was. And for one or two species of Dischidia, even when they flower, the experts cannot determine – or do not agree – whether they belong to the dischidias or to the hoyas.
Dischidia nummularia comes from South-East Asia and is an epiphyte, growing on the tree trunks. Because the flowers are small and often appear well above head height, they are difficult to spot. It likes plenty of light to grow well and if you are lucky you will get flowers, but it may take a while. It is an untidy grower and likes plenty of space. The plants can be grown in either a compost mixture or on a piece of bark or similar medium. Generally speaking, dischidias prefer a higher temperature than hoyas, but these two grow quite well in the same temperatures as hoyas. Both are very easy to propagate by cuttings and will, in summer, root in about six weeks.

 

Dischidia nummularia variegata GPS 10249

Dischidia nummularia GPS 10245