Sparmannia africana is a fast-growing plant that would normally grow into a small tree or large shrub in the wild. It features some amazing flowers, as they move whenever touched.
Sparmannia africana is also known as African hemp, African linden, house lime, or Cape stock rose. Originally from South Africa, Sparmannia africana grows in damp places on forest margins, hill slopes, in ravines, on rocky hillsides, and along streams near the southern coast of Africa.
A Sparmannia africana houseplant is a challenging specimen to grow, but it’s well worth the effort considering how well it responds to good care. It grows vigorously, produces fragrant flowers, and adds interest to any garden or indoor plant collection.
Sparmannia africana Attributes
Sparmannia africana is an easy-to-grow large shrub for a shady area in tropical landscapes. It has lush, soft, heart-shaped leaves and pretty white flowers that have a puff of gold and red stamens during spring and summer. It is tree-like, quickly growing several feet high when planted outdoors. The flowers appear in long–stalked clusters.
It grows quickly and tends to spread out gracefully, reaching a height of 6 to 10 feet in the wild. You can keep it pruned smaller in the garden, and when pruned more frequently, it makes a beautiful container plant.
The leaves are large and heart shaped with toothed edges, and fuzzy in texture. These leaves alternate along the stems, spiraling up to the growth tips. The leaf color varies from light to deep green.
African hemp produces clusters of small and delicate white flowers that hang from the ends of the branches. The blooms are slightly translucent and consist of five petals, forming a cup, and are usually elliptical in shape. These fragrant blooms are popular with pollinators.
The stamens are dual-colored, a combination of red and yellow. These stamens spread out from the center like a powder puff. The most fascinating thing about this unique houseplant is that these stamens move when touched.
This effect improves pollination by reacting to the touch of a bee or butterfly. The stamens puff out to ensure that they deposit pollen on the body of any visiting insect, a process known as “hyponasty.”
African linden has a long blooming season, flowering from spring throughout the summer when given the care it requires.
Once the flowers are pollinated, the plant produces a hard, rounded fruit, about 3/4-inch in size. Once ripe, the seed pod splits open to release its three seeds, each covered in a wrinkled shell.
Sparmannia africana grows quickly and may need repotting every year. You can keep excess growth in check and increase the density of the foliage by pinching out the stem tips of young plants.
Sparmannia blooms in early spring if it has been kept in direct sunlight during winter.
Sparmannia africana – Growing Guide
Growing Sparmannia africana is rewarding and enjoyable. Although it seems like the perfect landscape plant, it can thrive in a container environment with proper care.
With its spreading growth habit and attractive foliage, it makes an excellent choice for adding greenery and natural beauty to balconies, patios, or indoor spaces.
Growing Sparmannia indoors can mean a bit more commitment than other houseplants. However, many plant lovers find it worth the effort. It is a thirsty and hungry plant, but the speed of growth and fascinating flowers make it a popular choice for containers.
In this guide, we’ll explore the key considerations for successful Sparmannia africana care, including selecting the right container or outdoor location, providing the ideal growing conditions, and ensuring proper care to promote healthy growth.
Sparmannia does well in pots and can be grown indoors. It needs a well-ventilated location in the home, plus a generously sized pot. While it may tower up to 10 feet tall in the garden, you can rest assured that it won’t get over 6 feet tall in a container.
So, make sure you chose a container that provides enough room for it to grow as tall as you desire it to be.
However, make note that it won’t flower until it’s about 2 feet tall, so you’ll want to choose a pot that will accommodate at least that height.
Sparmannia africana is only hardy in zones 10 to 13 in the U.S. and may even need to be covered during cold spells in Zone 10.
If you choose to grow this plant directly in the ground, find a shady spot that only gets intermittent daylight. You’ll also want to make sure it has plenty of room to grow, so allow for several feet in diameter to provide enough space and adequate airflow.
If possible, find a location that remains protected from strong winds.
African hemp is a plant that likes loose, fertile soil that is well-draining. When growing in containers, choose a rich potting mix with plenty of organic matter and add a granular slow-release fertilizer to provide nutrients to support its fast-growing habit.
Sparmannia africana needs bright indirect light. When growing indoors in containers, you’ll want to be sure it gets enough sunlight. Place it in front of a south-facing window. Alternatively, you can add a grow light to ensure blooming.
However, it can get sunscald, so when growing outdoors — whether in a container or in the ground — it will need shade during the middle of the day when the sun is at its most intense.
When planting outdoors in the ground, locate your African hemp in dappled sunlight. It thrives beneath the canopy of taller trees. Sparmannia can also tolerate some direct sun early in the morning or late in the day near sunset.
Sparmannia africana likes moderate temperatures. It is not frost tolerant at all and should be brought indoors or covered when temperatures drop below 45 degrees Fahrenheit.
It thrives best at temperatures between 60 and 70 degrees.
Sparmannia africana is a thirsty plant, so keep the soil moist at all times. It’s especially to provide moisture when the plant is young or when it is grown in a container. You’ll likely need to water it daily in the summer.
When grown in the ground, you’ll need to water it very frequently during the first season and thereafter pretty regularly during the growing season.
During the winter, plant growth slows down, and your African hemp can be watered less frequently.
Because African hemp is such a fast-growing plant, it needs a lot of feeding to really thrive and reach its full potential. During the growing period, spring through summer, provide a fertilizer for flowering plants.
When grown in a container, feed your Sparmannia weekly.
You can feed Sparmannia grown in the ground every two to three weeks.
It’s a good idea to mulch your outdoor African linden every spring. Add several inches of compost and top with wood chips to ensure good soil fertility and improve moisture retention.
Sparmannia needs higher humidity levels at high temperatures. If you keep your African hemp outdoors in the summer, it may also require a boost of moist air to make the transition to the indoors more comfortable when brought inside in the autumn.
You can grow Sparmannia africana easily from cuttings or seeds.
To propagate from stem cuttings, use the shoots that develop at the base of the plant after pruning. Stick your cuttings into clean, wet sand or coconut coir. Provide a humidity dome or tent to keep the ambient humidity high around the cuttings.
You can also use semi-hardwood or hardwood cuttings in the spring. Choose a semi-rigid stem of about 6 inches long. Remove all but the last two to three leaves at the end of the growth tip.
Dipping your cuttings into rooting hormone can improve your strike rate from cuttings. For best results, bury your cuttings with at least two nodes in the rooting medium.
Maintain a temperature of 72 degrees Fahrenheit until new leaf growth appears. At that point, you can check for root development and add water if required.
Once roots are sufficiently developed enough to sustain the top growth, you can transplant them into pots with good quality potting soil.
Use a light seed sowing mix that has been well hydrated to start Sparmannia africana seeds. Cover the seeds with a light sprinkling of potting soil. Use a humidity dome or tent to keep the soil moist at all times.
Keep the seed cells at a temperature of 75 to 83 degrees Fahrenheit during the day, using a heat mat if necessary. Lower temperatures at night, down to 68 degrees Fahrenheit, is perfectly fine.
Remove the dome occasionally to prevent mold and mildew from overtaking your seedling. Once true leaves appear, you can remove the cover entirely. However, make sure you keep the soil moist at all times.
If you’re growing it outdoors, plant out African linden in the spring when nighttime temperatures have stabilized above 50 degrees Fahrenheit. Be prepared to cover in the case of late cold snaps.
Indoor Sparmannia will quickly deplete its potting soil, even with frequent feeding. So, in the spring, prune back your plant as necessary to retain the shape and size up prefer. Then repot with fresh potting soil as required to maintain good health. You may even need to prune the roots back a little to return it to the same pot.
If you’d like it to grow a little bigger than before, you can choose a slightly larger pot for your Sparmannia. We recommend increasing pot size by no more than 2 inches at a time.
When grown outdoors, prune your Sparmannia back hard to ensure it grows strong, dense, and bushy. They can become leggy if left to grow wild without regular trimming.
Indoors, prune Sparmannia back as required in the spring and as required throughout the growing season to keep it in check.
In both cases, it’s a good idea to prune back any stems with flowers to encourage longer flowering.
Common Problems and Solutions
Stress from lack of water presents as yellowing of leaves on Sparmannia, so be sure to keep this plant moist during the growing season.
One thing to note is that, although the plant isn’t toxic, the hairy leaves can irritate the skin. They may be mildly poisonous, and the effect only lasts a few minutes. However, it may cause contact dermatitis in some, so it’s a good idea to wear gloves when handling your African linden.
Excess moisture on the leaves can cause them to rot off and leave them prone to fungal diseases. So, it’s important to provide African linden with good ventilation.
Indoors, Sparmannia can get scale insect, whitefly, or spider mites. These are all removed by washing the plant down well with horticultural soap and a vigorous spray from the garden hose. For persistent infestations, use a cotton ball soaked in rubbing alcohol to remove the pests.
Raising the ambient humidity and watering frequently enough is a good way to prevent these pests from troubling your plant.
Sparmannia africana is a beautiful shrubby houseplant that produces lovely white flowers with fascinating stamens that move in response to touch. Their heady fragrance is due to both the foliage and the flowers, making them a welcome addition to any plant collection, indoor or out.
If you can provide them with room to grow, bright indirect light, and regular feeding and watering, they’re sure to reward your good care.
Editor’s Note: This post was originally published in February 2018 and has been completely updated.