Baobab leaves: growing in spring

Glencoe Baobab, Leaves

Glencoe Baobab, Leaves

The days are getting longer and my baobabs enjoy the sunshine on their windowsill in the living room. More daylight and the warmth bring out fresh green baobab leaves. Little tips appear at the ends of the branches. However, it can take a while until the leaves unfold fully.

Baobab sprouting new leaves

Baobab sprouting new leaves

Why do some baobabs in pots keep their leaves in winter?

This year most of my trees kept their leaves from the previous year. Usually they shed them on the onset of their resting phase in autumn. But with baobabs you never know – they seem to have a mind of their own when it comes to how things should be done. Currently I do not have a cooler space where I can keep my baobabs during winter. Therefore they are in a warm place all year round and I still need to water them regularly but with less frequency during winter. That is one of the reasons why they still carry their leaves.

5-digit Baobab leave, Heike Pander

5-digit Baobab leave, Heike Pander

Where do baobabs get new leaves?

In the meantime new leaves on the branches join the old ones. The shoots of last year are still green but not yet completely “woody”. Tiny reddish or greenish hairy spikes indicate where new leaves will appear. At these spots the trees either get new leaves or new branches.

Tip with sprouting baobab leaf, Heike Pander

Tip with sprouting baobab leaf, Heike Pander

Shape of baobab leaves

The leaf shape of the baobabs in pots is quite interesting. Usually, the first round that shows is single leaves which I consider normal. Even the big old trees behave like that. Only the second generation of leaves in one season consists of two, three or even more leaf parts. The five-part variant has prompted researchers to name baobabs Adansonia digitata. The five “limbs” of the leaves to them resembled the fingers of a human hand. The five-finger leaf style is similar to that of chestnut trees and appears mostly on older baobabs. On the other hand, I have seen most interesting variations appear with my baobabs in pots. Only last year did I come across simple leaves, five-part and even seven-part leaves on the same tree at the same time. The latter are rather rare.

Colour of baobab leaves

In healthy trees, the color of the leaves is a strong green, in some even dark green. Freshly emerging leaves are light green, but darken over time. If leaves take on a yellowish tinge they might suffer from different causes.

Different stages of wilting baobab leaves, Heike Pander

Different stages of wilting baobab leaves, Heike Pander

Slow down of baobab metabolism

Normally, baobabs slow down their metabolism in autumn which makes the leaves turn paler. Usually this process starts with yellow while the leave veins stay green longer. The more wilted the leaves become, the more they turn ocher or light brown. During this process they get drier and shrink. At the end of a life cycle, a leaf is dry, thin and breaks into pieces to the touch.

“Sick” tree, “sick” leaves

It might not be easy to tell if the tree follows the seasons once it sheds leaves or whether it suffers from disease or pests. If the latter is the case, one could detect signs of something feeding on the leaves. Collecting those insects from the leaves manually is easily done. Taking care of pests sucking the plant’s saps can be a bit more difficult to deal with – for example spider mites or lice. Spider mites cause little holes in leaves and leave fine threads everywhere. The tiny insects usually sit on the bottom side of the leaves and one can identify them as moving whitish or gray spots. Affected leaves turn yellowish in a more advanced stage of infestation.

Treatment of infected trees needed

In the case of heavy infestation, the leaves curl up and turn brown. This can damage the whole plant severely and may lead to its death if no steps are taken to cure it. Since spider mites do not like moisture and spread mainly in the dry and hot season (either in hot summers or with trees on the windowsill in rooms with central heating), showering the trees repeatedly with water often helps. After a shower of this kind the pot needs to dry well as baobabs are prone to root rot.

Baobab leaves indicating root rot, Heike Pander

Baobab leaves indicating root rot, Heike Pander

Root rot can be seen on baobab leaves

At a later stage the results of root rot can be seen on the leaves, too. Unlike the regular coloration of leaves in autumn, they get spots of a darker brown, may shrink and fall off. Sometimes only the leaf tips get dark brown and dry. If one of the baobabs has caught root rot it needs to be isolated from the other trees and taken out of the pot. Either replant the baobab in a new pot or clean the old pot thoroughly and replant in new soil. But before replanting the baobab, make sure to remove affected parts completely.

Baobab tap root, a few months old, Heike Pander

Baobab tap root, a few months old, Heike Pander

After a treatment like this the tree stands a chance to survive. Small baobabs have more problems to survive root rot as they do not have much root to cut yet. In any case it is best if root rot does not occur at all. Make sure that the soil has good water drainage and water baobabs reasonably. The best choice of soil is either a mixture of soil and river sand or ready-made cactus soil.

Little Baobab, germinated from seed in the wild

Little Baobab, germinated from seed in the wild

Watering baobabs properly

Rainwater is the best option for watering baobabs because it is often less calcareous than tap water. The amount of water needed is an estimation. Usually, I pour about 300 to 400 milliliters in a pot of approximately 24 centimeters in diameter. If water collects in the drip tray below I pour it out. As a matter of fact I do not water again before the soil in the pot is dry. An easy method to check this is by poking a finger into the ground. If the soil feels dry around the roots the tree needs water.

Baobab Seedlings 2016

Baobab Seedlings 2016

Growing baobab leaves faster

If you feel that the leaves take too long to come out in February / March, you can apply a simple trick. If your baobab has spent the winter months in a cool place take it to a warm spot and let the soil in the pot dry. Then pour a good load of water into the pot, let it drain properly and put the pot in a sunny spot. Baobabs love windows on the southern side of a room. Water and warmth in spring serve as impulse – like in nature – that the “rainy season” and with it the season of growth has arrived.

Baobab, Kruger Nursery, Kruger NP, South Africa

Baobab, Kruger Nursery, Kruger NP, South Africa

Baobab leaves in the wild

The best spot to observe baobab behavior is in the wild. The trees sprout their leaves before the rainy season arrives. Sometimes days or even weeks beforehand. They tab into the stored water in their trunks, roots and branches to support the new leaves. Leaves are important for the baobabs during the rainy season as they help the trees to survive heavy downpours and collecting water around the stems/roots. In addition, it allows the trees to refill their storage and to absorb as much water as possible. As a nice side effect: the trees do not have to remain in water for too long which prevents them from catching root rot.

Baobab South of Satara, Kruger NP, South Africa

Baobab South of Satara, Kruger NP, South Africa

Why do baobabs drop their leaves?

After the rainy season, baobabs drop their leaves. Not a drop of the vital water should be lost and leaves need lots of water. On average, baobabs bear their leaves for around three to four months. Most of the year they are seen “without” in the savannas and their bare branches point high into the sky. The bizarre view has earned them the name “Upside Down Tree” as the branches look like roots sticking out in different angles. It goes without saying that numerous myths surround the baobab. The most beautiful one is an explanation about why the baobab looks the way it does.

Baobab Fruit

Baobab Fruit

Baobabs extract water from fruit

The baobab does not only drop leaves to safe water. It has a mechanism that withdraws water from the fruit during the ripening process. The water is returned to its own water cycle. In the end, the fruits leave the tree when they are ripe. Again, not a drop should be wasted. As a result the fruits do not have juicy flesh like apples or oranges but dry fruit powder. After harvesting of the fruit the powder is sieved and thus separated from the seeds. It is packed into bags and sold as baobab fruit powder.

Baobab Fruit, Planet Baobab

Baobab Fruit, Planet Baobab

A baobab does not rest

During the dry season, the baobab reduces its metabolism, it does not “shut down” completely like beech or oak trees in Europe. Its survival of the dry phase depends on the stored water in special cells of the trunk, branches and roots. Not only baobabs benefit from that. Humans and animals alike use them as a living water source in some regions of Africa. However, storing water brings a disadvantage, too: baobabs cannot tolerate frost. They freeze to death like succulents would. That is why the frost line is limiting the natural distribution of the baobabs.

Baobab flower buds

Baobab flower buds

Baobabs in their annual life cycle

To me the fact that my baobabs behave like all deciduous trees in Europe is fascinating. As soon as the days get longer and the temperatures rise, they sprout their leaves. I find it a little “crazy” that my baobabs adapt to the European annual cycle, even though they come from the southern hemisphere. During our spring time their natural habitat is ready for fall and the trees should actually drop their leaves. I assume that the more intense daylight, the longer brightness and the rising temperatures motivate the trees to adjust their behavior.

Baobab Leaves, Window Sill

Baobab Leaves, Window Sill

Is your baobab well & happy?

A sure sign that the little baobab is doing well is a light green-gray shimmer on the trunk and the branches. Light green can always be seen on fresh shoots under the top cell layer. But even if the bark gets a little thicker, a light green-gray shimmer is visible. The green layer is made of chlorophyll. These are cells that help the tree produce its food. The tree can survive without the leaves. But they help it to absorb as much water as possible during the rainy season.

Baobab Flower

Baobab Flower

When do baobabs flower?

In addition, reproduction of baobabs falls into the rainy season. The trees produce flowers and start to bloom about four weeks after the leaves appear. With the flowers fully open pollination can take place. Once the rainy season is over the trees drop their leaves. Meanwhile the fruit grow on the tree. They are ready for harvesting at the height of the dry season. If you grow baobabs in pots it might take them a very long time to flower – and maybe they never will. So far, I have only seen baobabs in flower in the wild.

Baobab, Sagole Big Tree

Baobab, Sagole Big Tree

Baobab resting phase

From autumn in Europe, when the days get shorter, baobabs should be kept in bright and cool places at around 16 ° C. A winter garden is very suitable for this. Under no circumstances should they be kept in unheated greenhouses or on a terrace during winter. They do not tolerate frost. During their resting phase, baobabs reduce their metabolism and can live without leaves. During this phase they need less water. But not everyone has options to keep baobabs in a cooler place. They can make it on the windowsill all year long – but need less water during winter anyhow.

Clay Cone for watering

How to water your baobab during vacation

Baobabs are frugal contemporaries who need little nutrients and relatively little water. Only in very hot summers do I have to water them about every three to four days. But what happens if I can’t water them at all for example when I am off travelling? I take cones with small hosees from a garden center or specialized store. First I put the clay cones in cold water until they are soaked. Then I fill them with water, put the cap with the hose on each of the cones. For normal-sized pots I use one clay cone and stick it into the earth near the roots. Then I put the other end of the little hose into a container or bucket that I have filled with water.

Baobabs, watering system in place

Avoid flooding

The container should, if possible, be at the same height or better below the roots of the baobab. Otherwise the tree pulls too much water and can cause flooding. This method works for several weeks and guarantees that the plant survives my absence. The bucket has to be big enough tough. I have used the clay cones for many years successfully with my baobabs.

Can one eat baobab leaves?

Yes – and they taste lovely raw in a salad or cooked. In some of their areas of origin, people prepare a kind of spinach from young fresh leaves. When cooked, the leaves tend to draw threads which people like best. The older leaves are a little too hard and therefore do not make a good ingredient for spinach or salad. Traditional medicine uses baobab leaves, too. Science has confirmed that they have an antipyretic effect. Therefore traditional health pracititioners use them in combination with other herbs to treat malaria.

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