A Complete Guide to Growing and Caring for Mandevilla Plants

Mandevilla is a genus of spectacular lush climbing plants that are quite popular in Australian landscapes; particularly in warmer humid climates like Brisbane. Native to Central and South America, these plants are renowned for their lush foliage and dazzling, trumpet-shaped blooms. Here, we’ll explore their key characteristics, ideal growing conditions, and tips for care.

We’ll also discuss two new varieties capable of bringing those tropical vibes to colder Australian climates with mild frost.

Growth Habits

Mandevilla plants are natural climbers, thriving when given the opportunity to grow up trellises, arbors, or fences. Under optimal conditions, these vines can reach impressive heights of 3 to 5 metres, transforming vertical spaces with their lush foliage and vibrant flowers.

Certain varieties, particularly those sold as Dipladenia, take on a bushier, more compact shape, making them suitable for container gardening or small spaces.

Trumpet-Shaped Flowers

The flowers of the mandevilla are truly a garden highlight. Large, trumpet-shaped, and vivid in colour, they are available in shades of pink, red, white, and yellow. Their visual appeal, often accompanied by a delicate fragrance, makes them a favourite among gardeners.

They bloom from late spring through to autumn, provided proper care is given. Their trumpet shape favours pollinators with a long mouth-part like butterflies, as well as tiny pollinators that can fit their whole bodies within the structure.

Lush Foliage

Beyond their flowers, mandevilla plants are prized for their attractive foliage. The leaves are typically dark green, glossy, and oval-shaped, offering a striking contrast to the vivid blooms. Their foliage alone can bring a sense of tropical luxury to patios, balconies, or garden borders.

This lush foliage can be a great food source for so-called pests, particularly sap-suckers, which form the bottom layer of the food chain that feeds higher-level organisms like ladybeetles, birds, microbats and much more.

Ideal Growing Conditions

Like any plant, mandevilla thrives when its natural preferences are respected. Below are the key elements to bear in mind for their successful growth:

Light

Mandevilla does best in full sun to partial shade, with at least 4-6 hours of sunlight daily. More sunlight usually results in more abundant flowering, with some protection from afternoon sun recommended in hotter climates. Remember, they’re rainforest plants.

Temperature

Being tropical plants, mandevilla thrives in warm temperatures. They are frost-sensitive and typically flourish in warm, humid regions like their local range close to the equator in the Americas (and northern parts of Australia).

If you live in a cooler climate, they can be grown in pots and moved indoors during colder months; or, simply opt for one of the two varieties mentioned in this article which are both relatively frost hardy.

Soil

These plants prefer well-draining soil that is slightly acidic, with a pH range of 6.0 to 6.5. A mixture of ‘premium’ potting mix, sand/perlite, and organic matter is ideal for promoting healthy root development.

Watering and Humidity

Mandevilla requires consistent moisture but does not tolerate waterlogged soil. Allow the top inch of soil to dry between waterings. High humidity levels are beneficial, which is why they do particularly well in greenhouses or humid outdoor climates. In cooler climates, humidity can be encouraged in a sheltered microclimate.

Care and Maintenance

Regular care is recommended to keep your mandevilla thriving and looking its best:

Fertilising

To support healthy foliage and an abundance of blooms, mandevilla plants benefit greatly from a consistent feeding routine. Some gardeners like to use a water-soluble fertiliser rich in phosphorus, applied every two to four weeks during the growing season to encourage vibrant flower production and strong root systems.

Organic soil conditioners like compost, blood-and-bone and manure are also ideal, and can assist with improving both drainage and water retention in most soils (beware hydrophobicity in sand). Controlled-release fertilisers can also be added in spring and late summer to provide a steady supply of nutrients over an extended period.

Gardeners growing mandevilla in containers should complement these feedings with a bloom-boosting fertiliser every four to six weeks to compensate for nutrients leached from the potting soil.

It is important, however, to avoid over-fertilising (especially with nitrogen), which can result in excessive leaf growth at the expense of flowers. By adhering to a balanced feeding regimen, you can ensure your mandevilla stays healthy and delivers a spectacular floral display throughout the season.

Pruning

Pruning is an important part of caring for mandevilla plants, as it promotes vigorous new growth and encourages a profusion of flowers. Late winter or early spring is the ideal time to prune, just before the plant begins its new growing season.

During this period, vines can be trimmed back by about half, concentrating on removing any dead, damaged, or overcrowded stems to foster a more organised structure. Light pruning during the active growing season can also help maintain the plant’s shape and prevent tendrils from becoming too unruly.

When pruning, always use sharp, sterilised tools to minimise the risk of disease. Additionally, wearing gloves is recommended to avoid skin irritation caused by the plant’s milky sap. Proper and regular pruning ensures mandevilla remains lush while focusing its energy on flowering, rather than unchecked growth.

Providing Support

Climbing varieties benefit from support structures such as trellises or stakes, which guide the plant’s upward growth and showcase its flowers more effectively.

Training Young Plants

Most people like to plant a climber like a mandevilla at the base of a trellis and then hook the stems so that they are facing upward. This will help you achieve height quickly, but you may find gaps are left as the plant spends its energy growing upward instead of sideways.

Instead, try training stems horizontally along the base of the trellis to begin with. The plant will naturally send up side shoots as it tries to reach above the ‘canopy’ to reach the sun. This will usually allow you to create better overall coverage on the trellis.

Regularly inspect the plant as it grows, securing new tendrils to the support to encourage even coverage and prevent sprawling. Pinching back the tips of new shoots promotes branching, resulting in a bushier plant and more blooms.

For designs requiring symmetrical growth, cut back any stray stems and ensure the plant is equally trained on both sides of the support. Consistent care and attention during its early stages will create a mandevilla with bold architectural structure and maximum floral display.

Pests and Diseases

Common pests include aphids, spider mites, and whiteflies. Regular monitoring and treatment with white oil (made from vegetable oil, soap and water) can safely and quickly knock pests back.

Just like with all plants, effective long-term pest management for mandevilla plants involves an Integrated Pest Management (IPM) approach, combining preventative measures, monitoring, and targeted interventions.

Begin by ensuring that plants are grown in optimal conditions, so that healthy vines are better able to resist pests. Regularly inspect the plant for signs of common pests (especially sap-suckers), paying close attention to the undersides of leaves and tender new growth.

Encourage natural predators, like ladybirds and lacewings, to inhabit the garden as they help control pest populations organically. If pest issues arise, address them promptly with the least invasive solutions such as the previously-mentioned white oil or a jet spray from the hose.

All Seasons Red™

Mandevilla spp ‘MAND01‘ PBR Intended Trade Name All Seasons Red™

All Seasons Red™ Mandevilla captivates with its rich red flowers and tough resilience, handling light frost and heat with ease. Ideal for decorative use, it elevates garden spaces as a climber on fences and arches or as a stunning potted feature. Protect from mild frosts, and avoid heavy frosts.

All Seasons Pink™

Mandevilla spp ‘MAND02’ PBR Intended Trade Name All Seasons Pink™

All Seasons Pink™ Mandevilla dazzles with its hot pink blooms and excellent cold tolerance, thriving in light frosts and cooler climates. Its compact growth makes it perfect for screening, decorating arches, or brightening up patios in pots. Protect from mild frosts, and avoid heavy frosts.

How to Plant Mandevilla: Step-by-Step Guide

1. Choose the Perfect Spot
   Select a location with well-draining soil and full sun to partial shade. If planting in a container, ensure it has ample drainage holes and use a high-quality potting mix.
2. Prepare the Planting Area
   Enrich the soil in the chosen spot by incorporating compost or aged manure to enhance its nutrients and texture. Learn about your individual soil conditions and see whether further amending with products like gypsum or water crystals is advised.
3. Dig the Planting Hole
   Create a hole twice as wide as the mandevilla’s root ball and of the same depth to allow the roots plenty of room to spread.
4. Remove the Plant from Its Container
   Carefully take the mandevilla out of its pot. Gently tease out the roots to help them establish more effectively in the new location.
5. Position the Plant
   Place the mandevilla into the prepared hole, ensuring that the top of the root ball is at the same level as the surrounding soil. Rotate the plant to find the ‘best side’ to face the direction you’re most likely to be looking at it from, and the best angle for training stems.
6. Backfill and Firm the Soil
   Refill the hole with soil, gently pressing it down around the roots to eliminate air pockets but avoiding overly compacting it.
7. Water Thoroughly
   Give the newly planted mandevilla a generous watering to help the soil settle and provide the plant with much-needed moisture. (Ideally, you’d have given the ground a good soak the day before planting, too.)
8. Add Organic Mulch
   Spread a layer of organic mulch, such as chunky pine bark, around the base of the plant to retain moisture and regulate soil temperature. Keep the mulch slightly away from the stem to prevent rot.
9. Set Up a Support Structure
   If growing a climbing variety, install a trellis, stake, or other sturdy support near the plant. Secure the tendrils loosely as they grow to encourage upward climbing.
10. Monitor and Nurture
    Continue to water as needed, especially during dry spells, and watch for any signs of stress or pests as the mandevilla establishes itself in its new home.

Propagation of Mandevilla

Mandevilla plants are most commonly propagated through stem cuttings. The best time to take cuttings is during spring or early summer. Use a rooting hormone to enhance the chances of successful propagation.

Although growing mandevilla from seed is possible, it is a less common method, owing to the challenges involved. Keep in mind that plants protected by PBR (Plant Breeder’s Rights) cannot be propagated for commercial projects, only for personal use.

Indoor Cultivation

Many gardeners enjoy growing mandevilla in containers, making it easy to bring them indoors during colder months. When grown as an indoor plant:

• Place the pot in a bright, sunny location, such as a south-facing window. While they can survive indoors, they tend to do best right up next to a window that receives more than 4 hours of direct sunlight each day.
• Reduce watering during dormancy, as the plant’s growth slows in winter.
• To overwinter, cut back the plant and keep it in a cool, bright spot until spring arrives.

Toxicity Warning

An important note for pet owners and parents: mandevilla plants are toxic to pets and humans if ingested. They contain a milky sap which can also cause skin irritation, so handle them with care and keep them out of reach of children and animals.

Daniel’s Wrap

Mandevilla plants offer the perfect combination of ease of care and striking beauty, making them a popular choice for patios, garden borders, and balconies. Their ability to climb and their prolonged blooming season means they can bring life and colour to your garden throughout the warmer months.

With proper care and an understanding of their needs, mandevilla can reward you with years of stunning growth and vibrant flowers. Happy gardening!