Dipladenia is an intriguingly bushy plant with an unusual, downward growth habit. Initially reaching upwards, once the plant reaches a certain height its vines begin to cascade downwards. This makes it ideal for planters, containers and hanging baskets as well as the edge of raised beds or borders.
The small, pointy foliage of the dipladenia is often a glossy shade of deep green. This complements the plant’s fragrant, tubular flowers. Depending on the variety, the plant produces flowers in shades of light pink, deep red or orange.
Also known as rocktrumpet or funnel flower, this is a reliable, colorful addition to any sized garden.
In warm or tropical conditions the plants have a short flowering season. In cooler temperatures flowering can last for an extended period, possibly throughout the year.
An attractive plant with a colorful flowering habit, dipladenia is a popular garden flower or houseplant. It is also pleasingly easy to grow. Here is everything you need to know.
Varieties of Dipladenia
One of the most commonly grown varieties is Dipladenia Sanderi. This is a woody plant that produces trumpet shaped flowers on top of shiny, elliptical foliage. Adding to the attraction, Sanderie’s pink-red flowers have distinctive orange throats. Also known as Brazilian Jasmine this plant can reach up to 15 ft, making it a great choice if you have lots of space to fill.
Another reliable cultivar is the large, pink flowering Rio Dipladenia. A more compact plant, it can achieve a spread of 2 ft in ideal conditions. Rio is a tender variety. In cooler USDA Zones grow the plants in containers and place them outside once frosts have passed.
Rocktrumpet looks particularly attractive when grown in containers or hanging baskets. You can also grow the plants as houseplants.
Is my Plant a Dipladenia or Mandevilla?
An evergreen plant with an attractive flowering habit, dipladenia is a member of the Apocynaceae family. Originating in Southern and Central America it can also be found growing freely in Mexico, the West Indies and some parts of the Southwest United States.
Originally Mandevilla plants, such as Mandevilla vines, were classified as separate plants to the smaller, bushier dipladenia plants. Today all the plants are classified as Mandevilla. While they may look alike, there are some key differences.
It is largely the growth habit of dipladenia that sets it apart from the Mandevilla vine. Dipladenia is a fuller, more bushy or shrub-like plant than the vining mandevilla plant.
Mandevilla is a longer plant that produces largely vertical growth. In contrast, dipladenia likes to send its foliage trailing down towards the ground.
As well as the growth habit of the two plants, there are also differences in foliage and flowers. The leaves of dipladenia are typically narrower and more deep green in color than mandevilla leaves.
Dipladenia flowers are smaller than mandevilla blooms. They also tend to be pink or red in color while Mandevilla flowers come in a wider range of colors.
Where to Plant
Dipladenia plants are hardy and perennial in USDA Zones 9 or 10. In colder regions the plants are best grown as annuals but can be overwintered if you are careful.
A full sun loving plant, gardeners in the warmest USDA Zones should plant in a position where the plants receive some light or dappled shade during the early afternoon. This helps to protect the foliage from becoming scorched by the intense heat of the midday sun. Plants growing in containers can simply be moved to a shadier position as the day warms up.
Ideally these plants need 6 to 8 hours of direct or partial light every day. Happy to grow as a houseplant, indoors the plants do best on a sunny windowsill. If you struggle to provide enough natural light, try growing under grow lights.
Planting in a light, favorable position helps to encourage flowering. It also helps to keep the plant healthy.
Dipladenia does best in loamy or sandy, well draining soil. A pH level between 6.6 and 7.8 is ideal but the plants can grow in soils slightly outside this range. If you are unsure of the profile of your soil, invest in a soil testing kit. These are easy to use and provide you with all the information you need to create the ideal growing conditions for your plants.
Positioning Indoor Plants
If you are growing dipladenia as a houseplant, do not place it near a radiator or other artificial heat source.
Misting indoor plants helps to maintain humidity levels. It also helps to encourage flowering. You can also artificially raise humidity levels by placing the plant on a humidity tray filled with gravel and water.
If you choose to use a humidity tray, such as the 9GreenBox Humidity Tray, make sure that the container does not contact the water, instead it should sit on pebbles above the water line. Allowing containers to constantly contact water can lead to root rot.
Indoor plants can be placed outside from May until October for some fresh air. Remember to return the plants indoors before the temperature falls too far.
How to Plant
Dig the soil over well and work in organic matter, such as homemade compost, before planting.
If you are planting in containers or raised beds, fill them with a potting soil mix that drains well. Alternatively you can make your own potting mix. A mix containing equal parts, sand, leaf mold and peat moss is ideal.
Work the soil over, breaking up clumps of earth and removing stones, before planting. This helps to improve drainage. It is also the ideal time to work in organic matter.
Dig a large hole in the prepared soil. If you are unsure how large the hole should be, place the plant, still in its container, in the hole. The plant should fit comfortably in the hole, the lip of the container should be level with the soil.
When you are happy with the size of the hole carefully remove the plant from the container and position in the hole. Backfill the hole and water well.
Planting in Containers
Diplandeia is a pleasingly resilient plant. It tolerates being pot bound well. This means that you don’t need to regularly repot it. However an occasional repotting does help the plant to flourish and look its best.
The easiest way to check if your plant is becoming pot bound is to look at the drainage holes in the bottom of the pot. Roots sticking out of the holes is a clear sign that the plant is outgrowing its home. Other signs that it is time to repot your plant include the growth habit of the plant slowing or ceasing and the soil drying out more quickly than normal.
When planting for the first time, plant in a pot big enough to give the plant room to grow and spread. The pot should be clean and have drainage holes in the bottom.
After this, when repotting, don’t plant in too large a container. Instead use a container roughly the same size or a few inches larger. Avoid planting in too large a pot. Overly large pots hold more water which can lead to wet soil and root rot. Planting in a pot that is too big may also cause the plant to stop flowering.
Planting in fresh, rich soil helps the plant to establish itself. It also helps to reduce the chance of disease affecting your plants.
To plant, fill your chosen pot with fresh potting soil. Make a hole in the soil in the center of the pot. The hole should be large enough to hold the plant in its current container. Later, when repotting, the hole should be large enough to comfortably hold the plant’s root ball.
Carefully remove the plant from its old container. While some of the smaller roots may fall or break away, try to keep as much of the root system intact as possible. If you find the plant difficult to remove try squeezing the sides of the pot. This helps to loosen the soil.
Center the plant in the hole. When you are happy with the position of the plant, backfill the hole and firm the soil down. Water well.
How to Care for Dipladenia
Once planted, dipladenia requires little regular care in order to flourish. A member of the mandevilla family the plants share care requirements.
When to Water
When watering, don’t overwater the plants. Overly wet soil can cause root rot. In general watering well once every 8 to 10 days, depending on the weather conditions, is fine. During warmer periods the plants may require more frequent watering.
Water the plants slowly with a watering can. Allow the soil time to absorb as much moisture as possible.
Dipladenia plants can store some water in their roots. This means the plants continue to flower through short periods of drought so don’t worry too much if you forget to water for a few days. If you regularly forget to water your plants, why not try planting in self watering containers?
Knowing how often to water plants, particularly houseplants, can be difficult. Let the soil dry out between waterings. Mulching around the plants helps to improve drainage.
If you are still unsure, a measuring gauge such as the Atree Soil Meter provides you with an accurate way to measure the moisture content of your soil. It also tells you the pH level of your soil and how much light the plant is receiving. This is all useful information that you can use to grow happy and healthy plants.
Do I Need to Feed my Plant?
These are not plants that require lots of fertilizers. A slow release fertilizer applied in the spring is all the plants need to thrive.
Alternatively, you can apply a balanced liquid plant food no more than twice a month during the growing season. Cease feeding in August or when the plant stops flowering. After flowering the plant enters a dormant period, during this time it doesn’t require any fertilizer. This dormant period is necessary for the plant to flourish again next year.
How to Train the Plant’s Growth Habit
A low maintenance plant, dipladenia does not require pruning.
Pinching out new growth encourages the plant to become bushier. It also helps to curtail the plants trailing habit. This helps you to control the spread of the plant.
The best time to pinch out growth is in early spring or late winter. Pinching out should be avoided when the plant is in full flower.
Providing some support such as a trellis is another way to control and support the plants growth habit. The trellis is best positioned during planting.
In USDA Zones 9 and colder you should overwinter your plants indoors. This is also the case for any garden where the temperature threatens to fall below 65 to 70 ℉.
Position your plants in a light, or indirect light position away from any drafts. Cease feeding and water sparsely. Don’t let the soil dry out. Unlike other plants that you may be overwintering, don’t cut the dipladenia back. This prevents flowers from forming next year.
In the spring resume watering and feeding. As the nighttime temperatures consistently climb above 60 ℉ begin hardening off the plants. In a few weeks the plants can be left outside all night long. Just be aware of any sudden frosts which may harm or kill your plant.
How to Propagate
Dipladenia propagation is a pleasingly easy process. Some plants may be patented. These varieties can not be propagated unless you have the breeders permission.
How to Take Cuttings
Propagation is easily done by taking vine cuttings.
WIth a garden scissors cut away a decent length of mature vine. Cut away the lower leaves. Wash away any sap that may be dripping from the cutting.
Dip the cut vine into rooting powder. This encourages new growth to form but is not absolutely necessary for successful propagation. It just helps to speed up the process.
Once the cut area is dry, plant the cutting in a container filled with fresh potting soil. Place in a light, warm location. A greenhouse or on an east facing windowsill is ideal.
Keep the soil moist until roots form. The easiest way to do this is to gently spray or mist the soil. Once roots have formed, grow on as you would a larger plant.
You can also propagate the plants by layering. This requires you to bend a vine down so that it contacts the soil, either in the same raised planter or in a freshly filled pot next to the container. A 5 to 10 cm area of vine should contact the soil.
Cover the contacting piece of vine with fresh soil. Use a small stone to force the vine to remain in contact with the soil.
Keep the soil around the vine evenly moist. Roots should form in a few days. Once roots are established cut the vine away from the mother plant and grow on.
If planted and cared for correctly dipladenia is pleasingly easy to care for. Growing correctly also helps to avoid most fungal diseases. A fungicide can be used if you notice any sign of diseases.
Dipladenia is prone to attacks from aphids and spider mites. Regularly check your plants for signs of infestation. Wipe cotton wool dipped in neem oil or soapy water onto the foliage to remove any pests. Alternatively, making your own insecticidal soap is an easy way to keep plants healthy without resorting to using chemicals.
Warning Some people can experience skin irritation after touching the milk sap of the plant. To be safe, always wear gloves when handling the plant.
Attractive and pleasingly resilient, the dipladenia is a great addition to any garden. Happy to grow in a container, dipladenias can also be cultivated as houseplants.
A tropical plant with attractively showy flowers, dipladenia is a reliable addition to any garden. Best grown in containers or as a hanginging plant dipladenia also attracts scores of pollinators, butterflies and hummingbirds to your garden.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.