Tree houseleeks convince with their special growth habit. Their leaves develop at the shoot tip and crowd together in a plate shape, so that the plants appear bizarre.
In their original distribution area, the succulents have adapted to certain conditions.
Origin
Aeonium describes a genus within the stonecrop family (Crassulaceae). The 40 species are mainly found in the Canary Islands. Their namesake houseleek (Sempervivium) belongs to the same family and even subfamily Sempervivoideae.
Two representatives within the genus grow on Madeira, while the species Aeonium gorgoneum is native to Cape Verde. Other habitats are in southwestern Morocco and in the Semien Mountains of East Africa.
Of these species, Aeonium arboreum, which also bears the name Irish rose, is preferably cultivated as an ornamental plant. This species is native to the Canary Islands, where it occurs at altitudes between 650 and 5,000 ft (200 and 1,500 m).
Growth
Aeonium arboreum grows as a semi-shrub that develops branching as it ages. Its growth resembles the shape of a tree. While in nature the succulents grow up to 6.5 ft (2 m) high, in the culture they reach heights of growth up to 3 ft (1 m).
The shoot axes orient themselves according to the position of the sun. This gives rise to ascending and twisting growth forms. They grow 0.5-1 inch (1.5-3 cm) thick in diameter and have a smooth surface that is not reticulated.
Leaves
Fleshy thickened foliage leaves are typical of stonecrop plants, appearing in rosettes at the end of the shoot axis in Aeonium arboreum.
The leaf rosettes reach a diameter between 4 and 10 inches (10 and 25 cm). Fresh leaves emerge in the center of the rosette, initially pressed closely together.
The spatulate leaves, which are covered with light hairs on the edge, grow between 2 and 6 inches (5 and 15 cm) long. They are green in color and have a glossy leaf surface.
Some varieties also develop purple or variegated foliage. Red-leaved varieties lose their leaf coloration in shady locations. Under lack of light in winter, they may turn completely green.
Bloom
Between spring and summer, tree houseleeks develop cone-shaped inflorescences that spring from the center of the leaf rosette and grow between 8 and 12 inches (20 and 30 cm) tall.
The inflorescences contain numerous small flowers clustered together with golden-yellow-colored petals. The individual flowers follow a nine to eleven petaled structure.
During the flowering period, the plants draw the energy available in the leaves and invest it in the growth of the inflorescence. The leaf rosette withers over time.
Use
Tree houseleeks are primarily grown as foliage ornamentals. With their picturesque growth and showy flower panicles, they are ideal for creating pot gardens. They decorate interiors or conservatories, where you can cultivate them year-round.
During the summer months from the beginning of May until October at the latest, the plants can also decorate pot arrangements on balconies or terraces.
Are Tree Houseleeks Poisonous?
There is no evidence of toxic ingredients with tree houseleeks. You can use the plants for decorating children’s rooms without hesitation, and there is no danger of poisoning pets either.
In some countries, people even use the leaves medicinally or in small quantities for salads.
What Location is Suitable for Tre Houseleeks?
Tree houseleeks prefer a place with bright conditions all year round, where there is no direct sunlight. The ideal location is in a semi-shaded greenhouse or on a windowsill with western or eastern exposure.
Here the plants are protected from the direct midday sun. In the absence of light, though, the leaves become deformed and grow unnaturally long.
The winter garden is also suitable for growing, where the plants need room temperature. Between May and October, tree houseleeks enjoy a place outdoors.
What Kind of Soil Do Tree Houseleeks Need?
Tree houseleeks prefer a sandy substrate with small amounts of clay or loam. They grow best in moderately dry to slightly moist conditions.
Well-drained soil is conducive to growth. Tree houseleeks thrive in neutral substrates that are low in humus, making nutrients moderately available. A pH of 6.5 is ideal.
The perfect mix:
- 60 percent cactus soil
- 10 percent clay
- 30 percent mineral components
Propagating Tree Houseleeks
You have two ways to propagate your tree houseleeks. You can use cuttings or sow seeds yourself. Which of the methods is more suitable depends on how your tree houseleek has developed.
Cuttings
If your tree houseleek has formed branches, you can cut them off and propagate them as head cuttings. The mother plant should retain at least one rosette of leaves so that it can continue to grow.
Cut off a 1-2 inches (3-5 cm) long shoot at the beginning of the growing season. Allow the cutting to dry for about three days before placing the head cutting in the growing medium.
Place the planter in a bright location out of the direct sun. Make sure to keep the substrate evenly moist.
It will take between three and four weeks for the cuttings to develop roots. After six weeks, you can repot the young plants.
Seeding
Plants without branching can only be propagated by seeds. Scatter the seeds on a well-drained and nutrient-poor substrate consisting of cactus soil and sand.
The seeds need a lot of light and therefore should not be covered with soil. Cover the seed tray with a transparent container so that the soil does not dry out.
At the same time, the humidity should remain constant. At temperatures between 73 and 82 °F (23 and 28 °C), the seeds begin to germinate after two to three weeks.
Tree Houseleeks in a Pot
Tree houseleeks should be cultivated in a pot, as the plant is not suitable for outdoor use in areas with cold winters. Use an earthen pot, as it is stable and gives enough stability to the top-heavy plants.
You might also weight lighter pots with stones that you spread on the substrate. Unlike plastic pots, earthenware regulates the moisture content in the substrate because water can pass through the pores to the outside.
A drainage hole at the bottom of the pot is important. During the summer months, you can sink the tub in a suitable location in the garden.
Tree Houseleeks on a Balcony
Tree houseleeks will tolerate a balcony location, provided it offers wind- and sun-protected conditions.
Green-leaved varieties are sensitive to sudden changes in location, though. They need to be acclimated slowly to brighter light conditions as their leaves burn quickly.
Thick-leaved varieties with red leaves tolerate direct sunlight better. As a precaution, you should also not place these plants directly from a half-shaded windowsill into the direct midday sun.
Tree Houseleeks in a Greenhouse
In a greenhouse, you will find optimal conditions in terms of temperature and humidity for your tree houseleeks.
Make sure that the greenhouse is not exposed to direct sun. Frosted glass can help, as it provides diffused light.
During the summer months, the greenhouse should be sufficiently ventilated. In autumn, a change of location is necessary when the temperature in the greenhouse drops below 50 °F (10 °C) during the winter months.
Watering Tree Houseleeks
These succulent plants have a moderate water requirement. The root ball prefers a slightly moist substrate.
Water the plant when the soil has dried to a depth of 1 inch (3 cm). Use rainwater or stagnant tap water. If you forget to water once, the tree houseleek will forgive you.
But make sure not to overwater the plant as waterlogging will cause the roots to rot.
During the dormant period in winter, reduce the amount of watering to a minimum, so that the substrate does not dry out completely.
Humidity requirements:
- Water less in rooms with high humidity.
- Tree houseleeks tolerate low humidity.
- The plants must be watered more often in dry air.
Fertilizing Tree Houseleeks Properly
The nutrient requirements of tree houseleeks are low. In the first year, Aeonium arboreum does not need to be fertilized.
When the growing season begins in the spring of the second year, the succulents enjoy a small supply of nutrients. Give the plant a cactus fertilizer in a weak concentration every four weeks.
Stop fertilizing your tree houseleeks in September. Freshly repotted plants do not need to be fertilized in the same year.
Good to know
Tree houseleeks look particularly attractive between rock cordgrass and white stonecrop. This planting arrangement is reminiscent of the dry rocky deserts of the Canary Islands.
Pruning Tree Houseleeks Properly
As the succulents age, they branch out more and more. They grow both in height and width, so they might become too large for the windowsill.
Healthy tree houseleeks tolerate pruning without problems. Remove any troublesome side shoots when pruning. They can be used for rejuvenation.
If the plant develops flower panicles, they do not need to be removed immediately after fading. The plant will develop adventitious buds on the shoots that will sprout again.
How to Repot Tree Houseleeks Properly
It takes three to four years for the plant to fully root the substrate. You can orient yourself by the width of the plant. If the side shoots overhang the edge of the pot, repotting is recommended.
If you water the plant regularly with tap water, lime can accumulate in the substrate. Give the plant fresh substrate every one to two years to prevent it from becoming too chalky.
Overwintering Tree Houseleeks
Starting in mid-October, the tree houseleek needs a resting period. Place the plant in bright winter quarters, where the temperature does not fall below 50 °F (10 °C).
The care requirements of tree houseleeks during this period are limited. Since the plants do not shed their leaves, they need moisture even in winter.
Pests
When the air is very dry, Aeonium species are occasionally attacked by aphids. The pests draw plant juices from the leaf veins and cause unsightly discoloration on the leaves.
In winter, plants are more susceptible to pest infestation.
Mealybugs
Mealybugs secrete a white secretion, which wraps protectively around the body like a downy layer. Since an infestation can lead to growth disorders, the pests should be controlled actively or indirectly.
Preparations containing neem oil have proven effective for spraying the leaves. You can also use insecticide sticks that you insert into the soil.
Aphids
These rapidly reproducing pests should be sprayed with a stream of water. To control the eggs, spray decoctions of nettle or garlic on the leaves.