Dendrobium speciosum is a drought-tolerant, hardy orchid found in vast regions of Australia. It is commonly called rock orchid or rock lily. In Latin, the word speciosum means “beautiful” or “showy.” It belongs to the Dendrobium genus and the Orchidaceae family.
Read from our comprehensive flower guide and learn how to grow Dendrobium speciosum the right way.
What Is Dendrobium Speciosum?
Dendrobium speciosum is an epiphytic or a lithophytic orchid endemic to the east coast of Australia, where it can be found right from Victoria to Queensland in the north. It is a lithophyte which means that the plant grows in the crevices and nooks of rocks in its natural habitat. And an epiphyte is a plant that grows on tree barks and branches.
Dendrobium speciosum’s common names are the Outstanding dendrobium, the Sydney rock orchid, Cane orchid, and Rock lily. James Edward Smith described it first in 1804.
– Size and Growth
You can find Dendrobium speciosum from the coasts to the mountains in the Australian forests at a height of 3000 feet. It is suited for tropical and temperate climates. It usually grows on the rocks where its roots get nutrition from the leaf litter that accumulates in the rock crevices.
Dendrobium speciosum is a compact grower and remains small to medium in size. It can grow up to 1.5 to 2 feet long and 1.3 to 3 feet wide. It is pollinated by a stingless bee called Tetragonula carbonaria, which gets attracted to the plant by large, cream, and yellow inflorescences.
One interesting point to note about Dendrobium speciosum’s leaves is that its leaves can stay on the plant for as long as 12 years. The plants have pseudobulbs that can grow up to 18 inches tall.
Pseudobulbs are bulb-like formations that are formed above the soil. It is an enlarged section of the stem. Each pseudobulb has two to five leaves at the top. The leaves are tough and have a leathery texture.
Dendrobium speciosum grows well even when neglected and will reward you with a new flower spike every year. It has splendid, showy flowers that bloom in spring in clusters. It has fragrant, star-shaped flowers which can reach a height of 18 inches. The flowers are cream to yellow on the outer side and bright white towards the center. The central petal or labellum is spotted with distinctive, tiny burgundy or purple markings.
The blooms are 0.5 to 3 inches long and 0.8 to 3 inches wide. The arching flower spikes range from 2 to 30 inches in length. At one particular time, the number of flowers can be 2 to 200.
Dendrobium speciosum has dense roots that form thick beds across rocks and cliff faces. Its roots can spread far and wide in the wild. In pots, the plant grows well in compact conditions.
Dendrobium Speciosum Care
Dendrobium speciosum is easy-to-care-for and likes intermediate conditions for growth. Its cultivation is not difficult, provided you keep a few points in mind.
– Light Requirements
Dendrobium speciosum needs bright, indirect light to be healthy. For the plant to bloom more, keep it in sunny areas for longer periods. But remember to protect your plant from harsh sunlight during noon. The plant can handle direct sunlight throughout the day in autumn and winter.
To keep your plant healthy with maximum blooms, place it in part shade where it receives two to three hours of direct sun during morning or evening. Avoid keeping the plant in the dense shade also because too little light will discourage blooming.
– Water Requirements
Water Dendrobium speciosum when the potting media begins to dry. The frequency of watering depends on the growing media, the type of pot, the size of the pot, and the climatic conditions in your region.
Smaller pots need more frequent watering than large pots. Drier regions need more frequent watering and moisture than humid areas. Check the soil by inserting your finger in it till the first knuckle. If you feel the soil dry, water the plant. If the soil sticks to your finger, wait for some time and water when it is dry.
Dendrobium speciosum develops rapidly during the growing season. So in summer, water it abundantly, preferably every one to two days. Mist them regularly to maintain moisture, especially in dry regions.
Keep the watering minimal during winter. Water once in one or two weeks. A general rule for winters would be, if they look dry, leave them a couple of days and then water them.
– Soil Mix
Dendrobium speciosum grows well in a coarse media consisting of bark and perlite in the ratio 3:1. Any coarse orchid-growing mix works fine with this orchid. Add perlite, pumice, or charcoal for drainage and air movement.
For young plants, use fine bark as a growing medium. As they mature, move onto coarser bark. They need perfect drainage. So, sieve and wash the bark to remove the fine dust that clogs the media.
Apart from pots, the rock lily is also grown in hanging baskets and mounted on boards. You can mount your plant epiphytically on cork bark or tree fern by wrapping sphagnum moss around it and securing it with wires.
Dendrobium speciosum does not grow in the usual garden soil as it is not naturally adapted to constant moisture. Also, there is little air movement in regular garden soil. So, choose an appropriate orchid potting mix.
Dendrobium speciosum is a hardy plant that can tolerate extreme temperatures from near frost to hot conditions. It can bear a summer temperature of 113 degrees Fahrenheit and a winter temperature of 32 degrees Fahrenheit.
During its active growth period, provide your plant with warm growing conditions. Avoid placing your plant in frosty conditions for longer periods because the plant can go in shock. It can take 3-4 years for your plant to fully recover. Hence, protect your plant from both wind and frost.
Dendrobium speciosum thrives in low to medium humidity. A humidity level between 45 to 50 percent would be fine for its growth. Provide a good balance of humidity and air movement to your Rock orchid. Use a pot with drainage holes to maintain air movement.
Too much humidity without aeration leads to root rot and may even kill your plant.
Fertilizing during the growing season of spring to summer helps maintain plant health and leads to new growth. Fertilize your Dendrobium speciosum using a diluted orchid fertiliser and spray it once every one to two weeks. Do not fertilize during winter as the plant goes dormant during the colder season.
– Repotting Dendrobium Speciosum
Report a Dendrobium speciosum plant when the soil media starts to decompose. The ideal time to repot is in the early spring season. This helps in quick root development and gives the plant sufficient time to adjust to its new environment. Ensure that the potting media is firm and coarse at all times.
Dendrobium speciosum is a compact grower, and new growth or canes emerge close to the old ones. So frequent repotting is not required. While repotting, ensure that the roots are not disturbed.
Propagating Dendrobium Speciosum
Dendrobium speciosum can be propagated by dividing the clumps. Dig up the clump and divide the crown and root ball into two or more parts. Remove the rooted pieces from the clump and plant in a new pot or rock.
Seed propagation is difficult and requires help from specialists, making it impractical.
Dendrobium Speciosum Problems
– Fungal Disease
Dendrobium speciosum is prone to fungal diseases if it is overwatered or kept in high humidity. Use a fungicide to control fungal growth. Avoid overwatering the plant as it leads to a soggy, wet potting mix that further leads to root rot and other fungal diseases.
– Dendrobium Beetle
Dendrobium beetles are one of the most destructive orchid pests. They ruin the plant leaves, stems, buds, and flowers. It lays its eggs on new growths and flowers. You can also find them on the lower sides of the leaves. They affect orchids the most during summer and can destroy the plant’s new growth.
To get rid of this beetle, remove them during the evening or use soap water to clean the leaves regularly. Use insecticide if the plant is heavily infected.
Dendrobium speciosum is a must-have for all gardening beginners. It is a tough plant that can handle extreme conditions. Orchid lover or not, you must get your hands on this rewarding plant and fill your garden with colour and fragrance.
Let us take note of a few important points to remember:
- Dendrobium speciosum is an epiphytic or a lithophytic orchid species native to Australia
- It grows up to 1.5 to 2 feet in height and remains small to medium in size
- It is tough and drought-tolerant and can tolerate temperatures in the range of 32 to 113 degrees Fahrenheit
- It blooms the most in spring, and the flowers range from white to yellow with purple spots
- It grows well in bright spaces receiving morning and evening sun
- Harsh sunlight burns the leaves, dark conditions discourage flowering
- Water abundantly during the growing season of spring and summer
- For potting mix, use pine bark and perlite to make a coarse and well-drained growing media
- A humidity level between 45 to 50 percent works for the rock lily’s proper growth
- Maintain ventilation in the soil medium to avoid problems like root rot and plant decay
- Fertilize the plant using a liquid-based orchid fertiliser once every one to two weeks
- Repot the plant when the soil mix starts to decompose or during the spring season
- It can be propagated by division of the clump
- It faces problems like fungal diseases and dendrobium beetle
- Use a fungicide to deal with fungus and insecticide to get rid of beetles
Now that you know all about the Outstanding orchid, it is time for you to get yours and fill your home garden with this underrated but beautiful plant.
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