7 Tips for Growing Tropical Plants in a Greenhouse

yellow hibiscus - tips for growing tropical plants
Updated: October 11, 2019

Want the beauty of the tropics in your own garden? You can have it… but it’ll take some work. Tropical plants need warmth, sunlight, moisture… a pretty high maintenance bunch we might say. And given winter’s cold, dry environment, those needs are not easy ones to deliver, unless growing inside a well-maintained greenhouse. But by doing proper research into the unique needs of the plants you wish to grow and with proper maintenance, you’ll find it is possible to grow tropical vegetation in a greenhouse. Here are a few suggestions to help get you started.

Move plants around – Take special note of which plants need sunlight or shade. Make use of trays that will allow you to shift your plants throughout the garden greenhouse as necessary while allowing for proper water drainage. Also remember that some tropical crops, like the ficus, palms, or banana trees, need plenty of space to grow.

Maintain proper temperatures and air flow – Tending to tropical plants in a greenhouse requires special attention to the necessary growing temperatures and the required air flow to keep the air moist without growing molds. This is challenging to manage as you need to keep the greenhouse at a certain temperature—generally between 65 to 85 degrees Fahrenheit while never dropping below 40 degrees—while also providing satisfactory air circulation.

Rainforest environment – A mister system may also come in handy to keep your tropical vegetation at the correct humidity and maintain the required rainforest environment.

Consistent watering – Growing tropical plants in the greenhouse will also take consistent watering. Generally, every other day, though watering needs will depend on the kind of plants you’re growing. Here it is vital that you pay attention to your garden greenhouse temperatures and how rapidly it takes for your soil to dry. Higher temperatures mean soil should be watered more often to take care of a moist growing medium.

Clean plants – Keep plants thoroughly clean. Manage them properly by trimming lifeless material and inspecting them for pests. Handle these problems quickly to prevent them from scattering disease to other plants in the greenhouse. Molds can be an especially challenging problem when trying to grow tropical plants in a greenhouse and should be eradicated quickly when seen.

Lighting – Try several different lighting options in your garden greenhouse. Some tropical plants favor artificial or indirect lighting, and some are great with the filtered natural light produced by greenhouse panels. Do your homework before selecting various species of tropical plants to identify a combination that works best in your greenhouse garden.

There’s a lot to manage when raising tropical plants in a greenhouse environment, but the incentive in the long run will be the total satisfaction that comes with growing lovely plants that you don’t typically see in cold weather conditions.

Greenhouse Tropical Plants Buyer’s Guide

close-up of tropical plant leaves - growing tropical plants

Tropical Plant #1 – Cranberry Hibiscus / Hibiscus acetosella

Description

Cranberry Hibiscus (botanical name “Hibiscus acetosella”) is a short-lived perennial shrub that commonly grows in the tropics and subtropics. It can sometimes be grown in cooler climates as an annual. This plant makes a vibrant addition to the garden or your greenhouse, and one thing that separates this from other hibiscus is that the foliage is what draws people’s attention to the plant.

It rapidly grows to over 1.5 meters tall. The leaf color is a deep cranberry red, which is where it gets its name from. The flowers are of a tiny rose-pink hibiscus style. The leaves vary from plant to plant but are similar to the Japanese maple. Some can be partially green or completely red, and a lot of the time, you will find this plant to have a dark shaded foliage color.

The flowers of each plant are similar to their foliage but are commonly a little lighter of a color. This color makes for a nice contrast between leaves and flowers. For deeper burgundy foliage and leaves, you will find your flowers to be a lighter purple color with pink hues and tints.

It thrives in warm and wet climates and prefers full sun exposure, although it can grow in partial shade. Fertile, well-drained soil and lots of water are a must.

An interesting fact about these flowers is their use in drinks. While they contribute no taste at all, they provide a deep purple color that makes purple lemonade when combined with lemon, lime, sugar, and ice.

When growing in a greenhouse, the foliage of this plant works well as a darker backdrop for brighter flowers in the foreground. If you want to add some sizeable dark foliage that can add partial shade to other plants that need it, this will work great in the corner of your greenhouse.

Temperature needed to grow

The cranberry hibiscus needs hot and humid climates to thrive, and they can work exceptionally well in a greenhouse. They can, of course, grow in areas that aren’t as hot, but won’t grow as quickly.

Growing and care directions

Cranberry hibiscus plants are lower maintenance than other tropical plants. Keeping the plants moist is a good tip; however, do not leave them in damp soil.

Growing from seeds is relatively easy. Different from other tropical plants that have tiny dust-like seeds, these have large seeds that are easy to plant. They germinate quickly and grow rapidly from the start.

Fertilize every month, but do not overfeed your hibiscus as they grow rapidly. These plants can grow up to 5 feet tall and 2 feet wide in just one season, so controlling the growth with frequent pinching and pruning is necessary for a smaller greenhouse.

To control the size of this rapidly growing tropical plant, pruning will help maintain its bushy shape. Without pruning, this plant may grow much taller and, depending on the size of your greenhouse, could begin to overpower other plants. Frequent pruning and pinching from the start will help your greenhouse maintenance.

Tropical Plant #2 – Hibiscus trionum

Description

Hibiscus trionum is a summer blooming, short-lived perennial that is easy to grow. In the wild, it is an annual plant native to the Old World subtropics. After spreading through southern Europe, it eventually was introduced to the United States. Although in some areas of the world, this grows like a weed, it has such a beautiful bloom that makes it sought after by many.

The flower works great in pots and containers either outside in the right climate or inside a greenhouse. The plant forms a well-branched step with dark green leaves and produces beautiful hibiscus-type flowers. The bloom of the flower bears petals that are a white and pale green cream color that can contain faint hues of purple, and the center is usually a deep burgundy color. The center can also be an even deeper color that looks like crimson and sometimes even black.

Each flower lasts only a single day and blooms consistently all season long. The short-lived essence of this flower has given it the common name, “Flower of an hour.” Other common names include bladder hibiscus, bladder ketmia, shoofly, and venice mallow.

Growing this in a greenhouse will allow this flower to bloom on sunny days, but will usually stay closed during overcast cloudy days. The flower grows quickly when taken care of and thrives in the sunshine.

Temperature needed to grow

Hibiscus trionum grows best in hot, humid climates. Growing these flowers in a greenhouse that gets lots of sunlight and remains at more tropical or subtropical temperatures will be helpful for this flower. These flowers can survive in cooler temperatures; however, they won’t grow as quickly

Growing and care directions

This flower is very low maintenance and requires a lot of sun during the day for continued blooming. Plant this in a variety of fertile soil mediums and keep the soil moist but not swampy. You want to water this flower occasionally, but make sure you keep it in a pot or container that drains well.

If you are planning to start this from a seed, you may do so in containers. Germination is a rapid process. When the seedlings become large enough to handle, you can transplant them into a large pot or container. You can continue to prune them to keep their growth limited. However, you can also eventually move them outdoors, where they will grow even more rapidly, depending on the climate.

Because this flower is easy to grow, it works great as a filler plant. As long as it gets the full sun it needs, it can be grown around a variety of other plants.

Tropical Plant #3 – Heliconia wagneriana

Description

Heliconia wagneriana has the common names “Lobster claw flower,” “Rainbow Heliconcia,” and “Parrot beak plant,” among others, and does well mostly in sunlight. These tropical flowering plants are elegant flowers that range in size from a couple of feet high in containers up to 20 feet or taller when grown in the tropical wilderness.

These tropical plants are commonly cultivated throughout Central America. The flowers will bloom anytime between January and September, depending on the climate and temperature. They are usually found growing as wildflowers in the rainforests and wet tropics, in which they flower during the rainy season.

The leaves look very similar to some versions of banana trees with stems and flowers emerging from the center. The color of this plant varies but can commonly be found to be a red and orange hue with a waxy texture. When taken care of, the vibrance of this flower shines bright. The center of the flower will be a deep vibrant orange that fades off into a yellowish color. The outlines of the color will contrast to a light green color which makes this flower very attractive and easy to look at.

Temperature needed to grow

This plant and flower will thrive in tropical and semi-tropical climates. In the United States, they can be found in the states of Hawaii as well as Florida. These plants can still grow in cooler climates but will remain small and will take a longer time to bloom. It is recommended to grow these in a humid environment. If you don’t live in a hot and humid climate, you will need to use a greenhouse to grow these successfully.

Growing and care directions

Although these are tropical plants, they can do well in a greenhouse with tropical or semi-tropical climate control.

Full sun or partial shade will be best for growing these flowers and will bloom beautifully and full in sheltered locations such as a greenhouse. As with other flowers of its kind, this will grow taller in the shade than in the sun. Although it blooms beautifully in the sun, keeping it in the sun will limit its growth, which could be beneficial in a smaller greenhouse.

The soil should be well-drained but also remain consistently moist for the best effect. Changing or applying new mulch at least once a year will help this plant retain moisture. Overwatering will commonly cause root rot in these flowers. However, they should also not be left dry between watering, or else they may dry up and die off quickly.

Heliconia stems only flower once, and when flowering is complete and begins to dry up, it is wise to cut the stems to promote future blooming. This gives a cleaner appearance to your plant and will allow it to conserve its energy for future flowering.

If you plan to plant this flower from a seed, don’t plant it too deep, or else problems could arise. Also, planting from a seed will take some time for it to fully grow, and it could take over a year to see its first flower bloom. However, the beautiful vibrance of this plant is well worth the wait.

Tropical Plant #4 – Thai Red Roselle / Hibiscus sabdariffa

Description

The Thai Red Roselle (called “Hibiscus sabdariffa”) is also known by its common names, Florida cranberry, Jamaica sorrel, and red sorrel. Although these common names exist for the plant, it is actually native to West Africa and is also grown around the world.

The flowers that are produced from this plant are stunning, and the leaves are attractive as well. These plants can reach a height of 7 feet tall, but you can manage the height and growth of this plant in a container inside of a greenhouse.

An interesting fact about this plant is that a lot of the parts of the plant are used medicinally for a variety of illnesses. You can use the seeds, leaves, and roots of the Roselle. Some use the calyces to make sauce and jam and is commonly used in some herbal teas. The flowers of this plant are also edible.

Hibiscus tea is well known around the world, and commonly prevents hypertension and lowers blood pressure. It is rich in Vitamin C, so the application of this plant medicinally would help any illness you would take Vitamin C for. Besides the most common name of Hibiscus tea, you can get this specific flower when searching for roselle tea.

This plant is grown as a thick hedge as an annual. 

Temperature needed to grow

The temperature required for this flower to bloom and the plant to thrive is up to 95 degrees Fahrenheit. It can grow in Fahrenheit temperatures between 55 and 95 and does exceptionally well in moist, hot, and humid climates. Although they can grow in temperatures as cold as 55 degrees, it is recommended to give this plant the most humid environment you can for healthy growth to occur.

Growing and care directions

To grow this plant, higher heat is necessary and humid climates work much better for this plant. Using a mister inside of a greenhouse will work wonders for this plant.

For this plant to thrive, a minimum of 6 hours of sun per day is needed. It can maintain its growth in partially shaded areas, but having direct sunlight for at least a few hours each day is necessary.

It is recommended to start this plant indoors, which is why a greenhouse is perfect for growing this plant. However, the plant will grow quickly, and you might need to transplant this into larger containers by the end of the year.

If you are planning to start this plant from a seed, it is relatively easy, as well. Sowing your seeds in sandy loam is the best recommendation, but most seed starter mediums will work just fine. Make sure you water regularly and give your seeds and seedlings full sun as much as you can. You don’t need to fertilize the seeds or seedlings, but you may if you wish in small quantities.

While some varieties of this flower don’t begin flowering until October, this will flower sometime in August.  The soil must be rich in organic matter, and the plant should be watered daily. Do not overwater the plant or leave the soil damp.

This article was republished from Greenhouse Gardening.

featured image: Hiếu Hoàng; image 1: Talha R

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