carob tree // st john's bread

order: fabales
family: fabaceae
genus: ceratonia
species: siliqua (is there any possibility that it's a C. oreothauma?)
cultivar: from seeds obtained from a wild parent tree


When a friend of mine returned from the trip to South Africa earlier this year, he gave me different seeds he collected during expeditions in the wilderness including a seed pod collected from a carob tree. I have seen carob seed pods sold in supermarkets as food, but I don't know if there are still viable seeds in them. I have my seeds, so I probably don't ever have to find out.

On one fine day in July, I opened up the very hard pod and strained a lot of energy doing it. Since I didn't want to do damage to the seeds, I didn't want to use a knife. Instead I cracked it to bits with my bare hands. Seeds could then be knocked out from the pod. Next, I soaked the seeds in water for over 24 hours until they swelled. After that the seeds were sown in a pot of a standard potting compost. They sprouted in a couple of days, all of them. Since it belongs to the pea family or the legumes (fabaceae) -- a popular family of plants including acacia, mimosa and wisteria -- you can expect pinnate leaves on the plant. So far there are only two leaflets on each leaf. Young shoots are bronze in colour and turn dark green afterwards. The stems of the new shoots are thinly winged. The foliage is rather stiff and shiny. If you want to have any fruit at all, keep at least one male and one female plants. Yes, they are dioecious. I read that the flowers are initially bisexual or hermaphrodite. One sex will be suppressed in later development. So it's a good idea to keep several seedlings until the sexes have been determined.

As always I do things at the wrong time of year. Only two months after germination those sunny summer days are all over. Now we are already getting into autumn. Average temperature dropped down to 10°C in my area. So I brought the seedlings into my studies so they can continue to grow a bit more before the days get too short.

Carob trees grow best in calcareous soils. They should be kept above freezing temperature at all time. Water moderately and let dry out almost completely in between. It's unclear whether carob tree is able to fix nitrogen from the atmosphere. However it seems like they do not have the nitrogen fixing nodules present on some other leguminous plants. Assuming that its ability to fix nitrogen is weak, I believe it will be beneficial to give potted plants some weak balanced fertiliser occasionally. This should give the plant sufficient nitrogen and thus eliminate the need to use mycorrhizal fungi, which probably drains more energy from the tree than the tree can produce in low light condition in the winter, especially if the overwinter temperature is high enough for the fungi to stay active. As a rule I'd only use mycorrhizal fungi on plants that stay outdoors year round.

elephant bush

order: caryophyllales
family: didiereaceae
genus: portulacaria
species: afra

Elephant bush is a succulent shrub from the southern part of the African continent. It is very often mistaken for a jade (Crassula ovata), which is not even remotely related. I've got this plant in November 2011, as they were selling it at 3.50 euro -- a really good bargain I thought. It comes with a blue ceramic pot and a water retaining saucer. Elephant bush uses its glossy green leaves and dark brown-barked stems to store water. During water shortage, wrinkles appear on leaves. Bark is tender and is subject to peel, especially when wet, which can be quite harmful to plant. So care has to be taken not to injure any part of the trunk.

The plant grows very fast in the summer. In order to keep it in shape, new growth needs to be pinched regularly. With the stem cuttings you can create new plants. I've created many of them this year. I had so many that I had to give them away to friends. The cuttings root readily when inserted into moist soil. They will need some water only after new growth appears.

At any time keep the elephant bush above 10°C. In a heated room with bright light, it grows all year round. Let the soil dry out between watering. Fertilise with a cactus fertiliser, half-strength, as the higher content of potassium (kalium) encourages the formation of wooden bark, which makes the stem sturdier. It is important to dilute the recommended concentration by half because this plant cannot handle the concentration of salt that is meant for a cactus. Concentrated salt will draw water from the plant and cause its thick leaves to shrivel. If this happens, water the plant plentifully and let the water drip out from the bottom hole.

hearts on a string

order: gentianales
family: apocynaceae
genus: ceropegia
species: linearis subsp. woodii

One of the first summer days outdoor.

This is another plant from my dogbane family (Apocynaceae) collection, belonging to the subfamily Asclepiadoidea, earlier a separate family. Heart-shaped leaves hang on the thin pendent stem in pairs. They have grey-green marble marking above and are purple beneath. Bulbils form at leaf axils. Lantern-like flowers are likewise borne in pairs (one earlier than the other) at leaf axils and are spent when pollinated. This can happen in a few days to a few months.

It's an undemanding succulent, that can be kept indoor all year round as long as it gets a bit of sunlight each day. I grow it in a small clay pot with a standard potting soil which dries up rather quickly. Once completely dried, the soil doesn't absorb much water. I find it very practical this way, because I can just go ahead and water the plant freely everyday without having to worry about rootrot which very often causes the death of succulent plants. Although it can tolerate temperature down to 10°C, I'd keep it above 15°C.

I find pendent plants as troublesome as climbers. What I do now is, I let the plant hang down from the pot. When the bulbils grow bigger I'll move some of the them onto the pot so that they can root. Old bulbils will eventually die. How long they live, I don't know. But before they die, there will be enough offspring.

Blooming in August 2012.