Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
When is a flower not a flower? When it’s a spathe, of course. A flower is actually just the male and female reproductive organs. The colorful petals or bracts are just decoration, usually to attract pollinators. A spathe is a type of bract and on anthuriums, is the most colorful part of the plant.
What are Anthuriums?
Anthuriums are tropical plants native to Central and South America. They are part of a genus that is made up of 1,000 species of plants. The anthuriums most commonly grown in our homes are just two species, A. andreanum and A. scherzerianum. Both are only hardy in zones 10 through 12. Fortunately, they are both shade plants so they do well in our homes as houseplants.
The plants are 12 to 18 inches tall with large heart shaped leaves. The flowers consist of a colorful spathe which can be red, pink, white or bicolor, and a spadix which contain the male and female flowers or reproductive parts. The spadix grows in the form of a spike and can be white or yellow. When pollinated, the spadix produces berries. Each berry contains two seeds.
Anthuriums don’t bloom profusely. Mature plants produce 4 to 6 flowers each year but the individual flowers last about 6 weeks. Bloom time is year round. The flowers work well as cut flowers. They will last several weeks in a vase.
Are Anthuriums Poisonous?
Never eat any part of an anthurium. Keep the plants away from children and pets. They contain oxalate crystals which can cause digestive distress, breathing problems and skin rashes. Always wear gloves when handling the plants and then wash your hands thoroughly afterwards.
How to Grow Anthuriums
Anthuriums can be grown outdoors in zones 10 through 12. They must be grown in the shade. The plants cannot tolerate direct sunlight because they are forest plants originally. They will need well-drained soil.
Most of us grow them as houseplants. They can be brought outdoors during the summer as long as you keep them in a shady location. Indoors, they prefer indirect sunlight. Rather than placing them on a windowsill, put them on a stand or table that is 5 to 8 feet away from the window.
There are tropical plants which like to be very warm. Their ideal indoor temperature falls in a range of 60⁰F to as warm as 85⁰F. Make sure you keep your plants away from cold drafty windows and doors.
Anthuriums prefer what’s known as a soil-less mix which means that the “soil” in their containers should be a mix of peat moss, sphagnum moss and leaf mold with a handful of coarse sand or crushed brick. What you are going for is a well-draining medium that doesn’t contain a lot of nutrients. You will be supplying the missing nutrients with regular fertilizing.
Because the “soil” is lacking in nutrients, you need to fertilize frequently, using a regular houseplant fertilizer that is high in phosphorous. You can either fertilize every two weeks with a weak solution of liquid fertilizer or every month with full-strength fertilizer.
Water your plants sparingly. Allow the potting mix to dry slightly between waterings. If you have a saucer under your pot, be sure to empty it after watering so that your plant doesn’t sit in water. Anthuriums need high humidity, something that isn’t found in our homes because we use dehumidifiers to remove humidity and prevent the growth of mold. Mist your plant at least weekly to provide the humidity that it requires.
How to Grow Anthuriums From Divisions
Your anthurium will need to be repotted every 2 years or when the roots have filled their container. Up pot them to a container that is 1 to 2 inches larger. This is a good time to divide your plant. You can gently pull it apart and plant the resulting divisions in their own containers. The divisions may not produce as many flowers as the parent plant the first year.
How to Grow Anthuriums From Aerial Roots
As your plant grows, you will notice roots that are growing out of the pot and into the air. These are known as aerial roots. They are common in plants that grow in trees as an adaption to life above the ground. It’s just another way that the plants reproduce. You can just push these roots back into the soil or you can cut them off to make new plants. Dip the cut ends in rooting hormone and gently push them an inch or two into a pot filled with the same soil-less mix that the parent plant is growing in. The root will start to develop stems and leaves within 4 to 6 weeks.
How to Grow Anthuriums From Cuttings
Anthuriums are easy to grow from cuttings. Choose a stem that is at least 6 inches long and has two or three sets of leaves on it. Dip the cut end of stem in rooting hormone and then gently push it up to the first set or leaves into the same soil-less mix that you use to grow your plants in. Water the cutting thoroughly and then water as you would an established plant, allowing the soil to dry slightly between waterings. Mist your cutting weekly to provide humidity. Your cutting should develop roots within 4 to 6 weeks. You will know that roots have grown by the new growth on the top of the plant. Plants cannot produce new growth if they have no roots so new leaves are an indication that your cutting has started to grow roots.
How to Grow Anthuriums From Seed
Getting your anthurium to produce viable seeds can be tricky. It’s best to have more than one plant because the male and female flowers bloom at different times. With more than one plant, you have a better shot of having some male and some female flowers blooming at the same time. Once pollinated, berries are produced. They can be yellow or orange when they are ripe.
Remove the seeds from the ripened berries. Clean any remaining pulp from them and then allow them to air dry for 1 to 2 hours. Once the seeds are dry, you can sow them in the same soil-less mix that you grow your plants in, barely covering them. They should be planted no more than ⅛ inch deep. The soil-less mix should be premoistened and after the seeds are planted, gently mist them. Keep them at a temperature of 80⁰F to 85⁰F and mist regularly to keep them moist. Germination should occur in 5 to 7 days. Anthuriums that are grown from seed will take 2 to 3 years before they start blooming.
Questions & Answers
Question: What is causing the leaves to have big brown spots on them?
Answer: It sounds like your plant is getting too much sunlight. Anthuriums are shade plants. If you are growing your plant outdoors, transplant it to a shady area of your yard. If you are growing your anthurium indoors, move it away from the window. The further away from the window, it is, the less sunlight it will receive.
Question: Can you buy premixed potting soil for Antheriums?
Answer: Yes, buy soil that says it is for starting seeds. That is a sterile soil-less mix which is suitable for antheriums.
Question: How do you get rid of fruit flies around this plant?
Answer: I would use yellow sticky traps. You can hang them or place them on metal stakes. Just be aware that if you are using them outdoors, the traps will also capture beneficial insects that you need in your garden. If you are using them indoors or in a greenhouse, this is not a concern.
© 2018 Caren White
Caren White (author) on December 29, 2018:
Thank you Viet for your kind words.
Viet Doan from Big Island, Hawaii on December 29, 2018:
This is a wonderful article, packed with excellent tips and information for growing anthurium! One of my favorite tropical flowers, so many varieties in every color, size, and shape. As you said, anthurium blooms do last forever in the garden or in a vase! Thanks Caren for such a delightful reading.