How to Grow and Care for Philodendrons Outdoors
Philodendrons, a favorite and iconic houseplant for many, have a hidden charm. Some varieties can thrive as perennial garden plants in tropical southern regions.
Philodendrons are fast-growing, vigorous plants known for their beautiful, glossy, leathery leaves. Once established, they can even produce attractive flowers similar to those of calla lilies (Zantedeschia).
Main Types of Philodendrons
Philodendrons can be broadly divided into two types: arborescent and vining.
Arborescent philodendrons are relatively cold-hardy. These shrub-sized plants have large leaves and sturdy stems, growing upright without support. While they can be grown indoors, they require much more space than typical houseplants.
Arborescent philodendrons can be grown outdoors in coastal and tropical southern regions, corresponding to USDA hardiness zones 9-11. When used in landscaping, they prefer partial shade. In areas with strong light, it's best to provide shade during the hottest part of the day, though they can tolerate significant shade.
They are excellent for creating a tropical ambiance or making a dramatic silhouette against walls or windows in landscaping. They also look stunning when planted in large pots and can create a lush, exotic, tropical feel around swimming pools.
Vining and self-heading philodendrons include a variety of more delicate plants with two distinct growth habits. They can be grown outdoors in tropical southern regions (USDA Zones 10-11) and require partial to full shade.
Outdoor philodendrons are attractive for their unique leaf shapes and sizes. Self-heading types grow short and broad, with leaves radiating outwards from a central point.
Vining types do not climb on their own, so they need to be tied or leaned against a support. Over time, the plant will naturally conform to the shape of the support.
Almost anything can be used as a support, but poles that can absorb and retain moisture are especially good. For example, tree fern trunks, totem poles made with wire and sphagnum moss, or pieces of bark can be used. Keeping these supports moist will aid the growth of vining philodendrons.
Philodendron Care
Whether grown in pots or directly in the ground, all philodendrons require fertile, loose, and well-draining soil.
Philodendrons do not like strong morning sun or hot afternoon sun. Therefore, it's best to plant them in a location that receives morning sun and afternoon shade.
If you are growing philodendrons as perennials in outdoor pots, it's best to use soil rich in organic matter or a specialized horticultural potting mix.
Philodendrons thrive in consistently moist conditions but should not be left waterlogged. They dislike constantly wet roots.
Light
Choose a location that receives ample light in the morning and shade in the afternoon. It's crucial to maintain appropriate humidity and temperature while protecting the leaves from scorching sunlight.
Soil
Philodendrons thrive in soil rich in organic matter. Whether planting directly in the ground or in pots, use fertile, loose, and well-draining soil.
Watering
Philodendrons thrive in coastal and tropical southern regions, which are characterized by high humidity and temperature.
To ensure healthy growth, maintain consistent moisture in the pot or garden soil, avoiding excessive dryness. However, it's best to prevent waterlogging and continuously wet roots.
Temperature and Humidity
USDA Zones 10-11 are characterized by hot and humid conditions. While these climatic conditions are difficult for humans to control, philodendrons are plants that thrive in such natural environments.
According to Dr. Gary Bachman, a horticulturist at Mississippi State University, philodendrons adapt well to the hot and humid conditions that naturally occur in this region, making them a good plant choice.
Fertilizer
Bachman recommends using a commercial fertilizer like Miracle-Gro twice a year.
When using fertilizer, be sure to follow the dosage and instructions on the product packaging.
Types of Philodendrons
Thaumatophyllum bipinnatifidum
An arborescent philodendron. It grows into a tree-like shrub, reaching about 1.2-3m in height and 1.8-3m in width, typically with a single upright trunk that may lean sideways with age.
The leaves are deeply lobed and can grow up to 90cm long, with petioles of similar length.
'Hope' is a relatively compact variety, about 1.2m tall and wide, and is known to be more cold-hardy than the species.
P. domesticum
A vining philodendron. Often sold as P. 'Hastatum'.
It can grow up to 3-6m tall, with bright green, arrow-shaped leaves up to 60cm long and 30cm wide.
P. erubescens
Can grow up to 3-18m tall, with dark green, heart-shaped leaves up to 30cm long. The undersides of the leaves exhibit various colors.
In excessively warm and humid conditions, leaf spot disease can occur. There are various selected cultivars and hybrids that are more resistant to leaf spot and grow relatively compactly than the species.
'Royal Queen' produces bright red new leaves, with mature leaves turning dark green strongly mixed with red.
'Pink Princess' features glossy leaves ranging from blackish-dark green to deep burgundy, with scattered white and pink variegation. It shows more vibrant colors in brighter light.
P. hybrids
'Lynette' is a self-heading type that grows up to 30cm tall and 60cm wide. It has dense clusters of broad, bright green leaves, about 30cm long, with deeply indented veins creating a distinctive pattern. It's a good variety for tabletop display.
'Xanadu' is a self-heading type that grows up to 90cm tall and 1.5m wide. It features large, glossy green leaves that droop downwards and are deeply lobed.
'Autumn' is a self-heading type that grows up to 60cm tall and wide. New leaves emerge coppery-red and transition through red, orange, and yellow to glossy green as they mature.
'Cobra' is a vining variety characterized by white splashes and spots on its oval leaves.
P. martianum
A self-heading type. Grows up to 60cm tall and 90-120cm wide.
It features more than 12 leathery, lance-shaped, dark green leaves, densely clustered, each about 45cm long and 15-20cm wide, on short, broad petioles. Each leaf has a broad central vein, and the petioles are swollen and spongy with deep grooves, growing up to 38cm long.
Its large, spreading leaves make it excellent for use as a groundcover.
P. melanochrysum
Black Gold Philodendron.
A vining type, growing 3-6m tall, characterized by velvety-textured, greenish-black, lance-shaped leaves. Leaves can grow up to 90cm long and 30cm wide.
The central and lateral veins are pale green, and new leaves emerge heart-shaped with a slight coppery tint.
P. scandens
Heartleaf Philodendron.
One of the most common philodendrons, it can grow up to 15m. It features dark green, heart-shaped leaves, with young leaves measuring about 10-15cm and mature leaves up to 30cm.
P. s. micans has a velvety texture on young leaves, which become smooth as they mature.
P. s. oxycardium, often sold as P. oxycardium or P. cordatum, maintains glossy leaves regardless of its growth stage.
Both varieties are particularly popular as young plants and are used as houseplants on tree trunks, in hanging baskets, or window boxes.
Indoors, you can use strings or wires to guide them in various directions to create decorative shapes, and growing them on moisture-retaining poles is also a good method.
P. wendlandii
A self-heading type. Grows up to 30cm tall and 60cm wide.
It has more than 12 broad, lance-shaped, dark green leaves, about 30cm long, densely clustered on short, broad petioles.
Indoors, it's suitable for spaces that need a sturdy yet compact-leaved plant.
P. williamsii
An arborescent philodendron.
It has glossy, dark green, arrow-shaped leaves that can grow up to 75cm long and 30cm wide. The petioles grow long, almost as long as the leaves.
Pruning
Pruning is not strictly necessary to maintain the health of a philodendron.
However, if the lower leaves start to turn brown or look unhealthy, you can cut them off to keep the plant looking tidy overall.
Repotting and Pot Care for Philodendrons
Large philodendrons are difficult to repot, so it's best to plant them in a sufficiently large pot from the start.
Once the plant is mature, continue to care for it to ensure it thrives in its current pot.
Winter Care
In USDA Zones 9-11, temperatures can occasionally drop below freezing, but it's not always necessary to move plants indoors in such cases.
When a sudden cold snap occurs, covering the entire plant with a frost blanket or cloth can help protect it from temporary low temperatures.