The large, heart-shaped leaves of the African linden (Sparrmannia africans) give it its name, which is similar to that of the deciduous Tilia tree.
After a few years in obscurity, this woody plant is once again becoming a better-known houseplant.
Origin
The botanical name of the species, Sparrmannia africana, already gives it away: the plant originally comes from the African continent.
The Swedish physician and botanist Anders Sparrmann discovered the plant as early as the 18th century and then introduced to Europe. His name remains immortalized in the botanical name of the plant.
Later it was Carl von Linné junior, the son of the famous Swedish botanist and naturalist of the same name, who described and established the genus.
As a plant of the African south, the African linden, also known as African hemp, is adapted to light, moderately humid, and comparatively cool habitats.
Unlike many other houseplants that originated in Africa, its original environment is not a tropical one. Thus, year-round indoor cultivation is possible with no problems at all.
Origin in short:
- African linden originates from South Africa
- Its habitat of origin is rather cool, medium humid and bright
- Anders Sparrmann discovered the plant and introduced it to Europe
- Carl von Linné jr. first described the plant
Growth
The habitus of the African linden, which belongs to the mallow (Malvaceae) family, is a shrub- to tree-like. With its widely branching shoots, it forms a very expansive crown above a more or less distinct trunk.
In its native country, the African linden can grow up to 23 ft (7 m) high. But in the local indoor cultivation, it is rather content with a maximum of 10 ft (3 m), due to the lower light availability and the repeatedly necessary pruning.
Growth characteristics at a glance:
- Shrubby to tree-like habit
- Forms a widely branched, spreading crown
- Can grow up to 23 ft (7 m) high in its native habitat, here rather only 10 ft (3 m) high
Leaves
The leaves of the Sparrmannia africana are the main reason for its trivial name African linden. This is because, with their large, heart-shaped appearance and their light green color, they are indeed clearly reminiscent of the leaves of real lime trees.
However, if you look closely, you will notice a few differences. First of all, the leaf contour is characterized by angular bulges on the leading edge at an advanced age. No linden species has such a shape.
Moreover, due to their somewhat raised veining, African linden leaves have a wavier, not so fine, and smooth surface texture as linden leaves. However, they still have a delicate consistency, and they are also setose.
The leaf margins are cove-dentate. Overall, the leaves can reach a stately length and width of up to 8 inches (20 cm). The stems also grow to about this length.
Leaf characteristics in brief:
- Heart-shaped, large-surface form reminiscent of linden leaves
- With pointed, frontal bulges at a higher age
- Light green color
- Slightly wavy surface texture, densely setose
- Up to 8 inches (20 cm) long and wide
Flowers
Provided that you generally cultivate the African linden in a cool place and do not cut it back in the spring, you can enjoy very pretty flowers throughout the winter and spring months.
The flowers show up with delicate, white petals and a large, yolk-yellow, and rust-brown bush of many, long stamens. The individual flowers, which are erect when they open, stand together in large umbels.
Flower characteristics at a glance:
- Show up prolifically when grown in cool conditions and moderately pruned back
- Large, handsome appearance with white petals and yolk-yellow-brown stamen cluster
- The flowers stand together in large umbels
When is Flowering Time for African Linden?
The individual flowers of the African linden have a relatively short retention period, but the entire flowering period is all the longer.
At least from November until May, new flowers can open on the umbels again and again. By consistently cutting them off after flowering, you can stimulate their regeneration.
If cultivated in permanently cool conditions, the African linden can also bloom all year round.
To remember:
- The flowering period of individual flowers is only short
- The flowering period as a whole is from November to May or even all year round
Fruit
If you maintain frequent exchange of air between indoors and outdoors in your home, and accordingly enough insects can pay your African linden a visit, the chance of pollination of the flowers is higher.
However, aiming for fruit formation is especially useful if you plan to propagate from your own seeds.
The fruits have a capsule-like shape and are enclosed in a prickly sheath, which actually serves to strip and further transport by animals.
Which Location is Suitable for African Linden?
According to its home on the South African coast, the Sparrmannia africana prefers a comparatively cool and airy location for houseplants.
It prefers a temperature of 59 to 65 °F (15 to 18 °C). If you always like it warm at home, you may be in a bit of a predicament.
However, in order not to have to do without the impressive foliage ornamental plant, in this case, you could also consider a location in the stairwell.
The African linden wants a lot of light, but not direct sunlight. So shade it on an east or west-facing windowsill with other plants or a light fabric if possible.
In summer, you can also put the African linden outside.
The humidity should be relatively high, though.
Location requirements at a glance:
- Bright, but without direct sunlight
- Rather cool temperatures of 59-65 °F (15-18 °C)
- Fairly high humidity
What Soil Does African Linden Need?
The nutrient requirements of the African linden are medium. It is best to place it in a mixture of normal potting soil and a small amount of mature compost and/or a handful of horn shavings. A little loosening with sand is also recommended.
It is also possible to keep them in hydroponics with a soilless substrate of expanded clay and a permanent water-nutrient root bath. This variant can be a solution especially for offices or for people who are at home irregularly.
Watering African Linden
In terms of watering, the African linden needs a relatively large amount of attention. So, if you do not want to water constantly, hydroponics is a good choice.
Especially during the main vegetation phase over the spring and summer months, you need to provide it with plenty of water.
Nevertheless, you should avoid waterlogging. So make sure that the substrate ball always dried well before each watering and that no water remains permanently in the saucer.
The humidity-loving African linden is not averse to an occasional shower from the water disperser.
In winter, reduce watering a little.
To remember:
- African linden is relatively thirsty
- It needs regular, abundant watering
- Nevertheless, avoid waterlogging
- Spraying is good for it
- Water less in winter
Fertilizing African Linden Properly
Due to its considerable nutrient requirements, it does no harm to fertilize the African linden regularly during the growth phase. Simply use a universal liquid fertilizer, which you add to the water every two weeks.
When potting, you want to enrich the substrate with organic permanent fertilizer in the form of compost and horn shavings.
During the winter break, reduce the additional fertilizer application to no more than once every three weeks or discontinue it altogether.
Fertilizer recommendations in a nutshell:
- Regular fertilization of the African linden makes sense due to its relatively high nutrient requirements
- In summer and autumn, apply a liquid fertilizer every 2 weeks
- Permanent nutrient supply through compost/horn shavings in the substrate
- In winter, fertilize at most every 3 weeks or not at all
Pruning African Linden Properly
The sprawling African linden needs regular pruning if it is not to take over the room completely in the long run.
However, it is not overly tolerant of pruning. For this reason alone, it is advisable to wait until the plant has reached an overly lush size and width before trimming it regularly.
Also, because it blooms much more abundantly when you don’t constantly disturbed it by pruning, you should refrain from shortening the shoots every year.
So the ideal pruning rule is: radical pruning, if it needs to be for space reasons, otherwise cut off only faded flowers. Radical pruning should be done in winter.
Wintering African Linden
The African linden can basically stand in the same location all year round, as long as the conditions are as species-appropriate as possible.
This means a rather cool, rather below living level temperature, preferably bright without direct sun and good humidity.
The winter months require rather a few changes in care. Thus, you should noticeably reduce both watering and fertilizing.
Propagating African Linden
The easiest way to propagate African linden is by cuttings. But sowing is also possible.
Cuttings
With this method, cut head cuttings of about 6 inches (15 cm) in length from the upper crown area. The lower part should be generously freed from leaves.
Root the cuttings simply in water or in a growing medium made of peat and sand, which you have to keep moist regularly.
You should place the cuttings in a warm, bright place, protected from direct sunlight.
Seed Cultivation
Alternatively, you can also grow African linden from seeds. If its mother plant has formed fruits, you can use your own seeds, but some are also available in specialized stores.
First, soak the seeds in water for at least 6 hours before placing them in planters with growing soil and covering them with some sand. It is best to cover the planters with foil to ensure an evenly moist and protected microclimate.
For germination, the seeds need a lot of light and warmth, about 77 °F (25 °C) is ideal.
After about two weeks, the seedlings should start to show. Then, lift the foil to give the seedlings air and grow them to a size of about 2 inches (5 cm). They can then be pricked out.
Diseases
Diseases and pests, fortunately, do not often afflict the African linden. Rather, care errors are responsible for any weaknesses, such as a too dark location or waterlogging.
In the latter case, root rot or mold can form, which the plant indicates with yellow and falling leaves. In this case, you should clean out the root ball thoroughly and place it in a fresh substrate.
Pests
The African linden does not want to be too warm and dry. Of course, this can happen in a heated room.
In that case, it becomes more susceptible to known heat- and drought-loving pests such as whiteflies, scale insects, or mealybugs.
The best way to deal with a whitefly infestation is to use sticky traps. The best way to fight scale insects and mealybugs is first to wipe them off mechanically and then to spray them with a mixture of spirit and soap and water.
Good to know
Because of its sprawling growth, it is advisable to place the African linden in a large clay planter. This way you will ensure sufficient stability. Also, you will not need to repot as often.
Beautiful Varieties
A few cultivars have emerged from Sparrmannia africana, which are quite different from each other in their appearance.
So you have a selection that, while not overly abundant in number, is quite diverse. The best-known varieties are the Sparrmannia africana Variegata, the Sparrmannia africana Flore Pleno and the Sparrmannia africana Nana.
Sparrmannia Africana Variegata
The distinctive feature of this variety is the whitish variegation of the leaves. It appears in a rather irregular structure on the distinctly veined foliage, which will certainly please symmetry lovers less.
Fans of unusual leaf decoration phenomena will like it all the more. The leaves have at least a triple, if not a quintuple, pointed heart shape. In the latter case, their contour almost resembles that of maple, rather than linden leaves.
Depending on the coolness of the site, the variety can show its white flowers with a yellow-reddish-brown center all year round.
Overall, the Sparrmannia africana Variegata grows up to about 11.5 ft (3.5 m) tall and grows out very bushy.
Sparrmannia Africana Flore Pleno
The name of this cultivar gives away what is so special about it.
The flowers are double and appear mostly in the spring and summer months in large, delicately structured, fiddly hemispheres with numerous white petals that change to yolk yellow and old pink in the center.
This certainly makes it the most magnificent of the African linden varieties.
Its foliage leaves the stage to the lush blooms and is a simple, light matte green with a multiple-pointed outline.
Their veining is somewhat more delicate than that of Sparrmannia africana Variegata, and at an advanced age and when they reach a certain size, they can easily overhang the stem.
Sparrmannia africana Flore Pleno, in contrast to its cultivars, prefers a sunny location. In height, the fast-growing plant can reach 10 to 13 ft (3 to 4 m), in width 6.5 to 13 ft (2 to 4 m).
Sparrmannia Africana Nana
The Sparrmannia africana Nana is a dwarf variety. It is therefore particularly suitable for fans of African linden trees who do not want to carry out radical pruning.
It is very possible to keep the plant permanently indoors without pruning. The unfilled flowers are white and can appear all year round.