When to Repot and Propagate Anthurium

Best season to repot: spring

NC State recommends repotting anthuriums in spring, every 2 to 3 years or whenever the plant appears rootbound.

Anthuriums are slow growers and do not need frequent repotting. Clemson’s advice is to let the root system fill the container before transplanting. There is no benefit to moving up early, and NC State lists root rot from overwatering as an anthurium problem, so keep the pot in proportion to the roots.

Signs it needs repotting

• Roots have filled the pot and are circling the outside of the root ball when you slide it out.
• Roots are growing out of the drainage holes or climbing above the surface of the mix.
• It has been 2 to 3 years since the last repotting.

Pot and mix

Anthurium andraeanum grows as an epiphyte on trees in the rainforests of Colombia and Ecuador, so its roots need air as much as water. Clemson recommends a soilless mix of peat moss, pine bark and perlite. Avoid dense garden soil or heavy potting soil, and use a pot with drainage holes.

When and how to propagate

Combine propagation with spring repotting. NC State lists division and stem cuttings as methods; UF/IFAS also mentions seed, though potted anthuriums rarely produce fruit, NC State notes.

Division is the most straightforward. When a plant has formed several crowns, slide it out of the pot, gently separate it into sections that each carry leaves and a share of roots, and pot each in fresh coarse mix. Keep the new pots warm, between 65 and 80°F, in bright, indirect light, and raise humidity with a tray of moist gravel while they recover.

Wear gloves. NC State notes the sap can irritate skin and eyes, and the ASPCA lists the plant as toxic to dogs, cats and horses.

When to move it outdoors for summer

In frost-free South Florida, UF/IFAS lists year-round outdoor planting in zones 10 and 11. Everywhere else, anthurium is a houseplant that can spend summer outdoors only while nights are warm.

Sources set the threshold for houseplants differently:

• University of Maryland Extension: move houseplants out only after night temperatures stay above 60°F, which it says is usually mid-May or early June in Maryland.
• Colorado State University Extension: wait until nights are above 50°F and all danger of frost has passed.

For anthurium, use the warmer 60°F line. NC State gives its preferred range as 65 to 80°F and warns that anthuriums do not tolerate cold drafts or sudden temperature changes, so a chilly night soon after the move is exactly what to avoid.

Put it in full or bright shade, never direct sun, which scorches the leaves. Maryland Extension recommends acclimating houseplants gradually to outdoor light, and Colorado State suggests shelter from wind. Maryland Extension notes houseplants need water more often outdoors, so check the top inch of mix frequently.

When to bring it back inside

Bring it in before nights cool. Maryland Extension says to move houseplants back as night temperatures begin to drop below 60°F, usually mid-September there. Colorado State’s deadline is before any danger of frost, but for a plant that prefers 65°F and up, that is too late.

Check it carefully before it comes in. Aphids, spider mites, mealybugs and scale all attack anthuriums, and Maryland Extension notes that outdoor pests kept in check by beneficial insects can multiply quickly indoors. Look under the leaves and along the stems, and check the drainage holes, where Colorado State says slugs and pill bugs hide. Maryland Extension suggests treating plants with a labeled insecticidal soap or horticultural oil before bringing them inside.

Indoors, place it in bright, indirect light away from cold windows and heating vents, and set it on a tray of moist gravel to keep humidity up.