Poinsettia: Indoor Plant Care & Growing Guide

Poinsettia is a perennial shrub native to Mexico. It is most often grown as an annual for winter holiday display, but it can also be grown as a perennial garden shrub in regions where winter temperatures remain above 50°F. Also known as Mexican flameleaf, these plants are forced into bloom in time for the holiday season, and they require specific care to look their best into the new year and beyond.

The familiar red specieshas been joined by even flashier hues thanks to hybridizers who have expanded the range of colors from the familiar scarlet to white, cream, salmon, yellow, and pink. Its blooms are a cluster of tiny yellow flowers surrounded by large brilliant (usually red) floral bracts, which are modified leaves.

Key Tips

These are some basic pointers to keep in mind for keeping your poinsettia healthy.

• Poinsettias usually bloom in winter and spring, then go dormant, but with the right care, they can be coaxed into reblooming the following winter
• Plant in a well-draining potting soil
• Maintain temperatures between 65°F to 75°F
• Bright indirect or diffused light is best
• Located near a window where it will get indirect sunlight and away from cold drafts is ideal
• Water when top surface of soil is dry; water less frequently during dormant stage of growth
  
• Contrary to a popular belief, poinsettias are not seriously toxic to people or pets. At most, they are mildly toxic to cats and dogs who ingest the plant material.

Poinsettia Care

Keep your poinsettia healthy and vigorous beyond January by using the proper care techniques. The trick: Provide enough filtered sun, warmth, and water, and your poinsettia will thrive. If you're especially motivated and follow a regimen of specific care, your plant might rebloom next holiday season.

If grown as a landscape shrub in warm climates, poinsettia requires a sunny location and well-drained soil. Frequent pinching back of the stem tips will ensure seasonal color in winter.

Light

Poinsettia do best when placed in bright, diffused sunlight, so place your plant near a sunny window where it will receive at least six to eight hours of diffused light per day. Be aware that exposure to direct sunlight can burn bracts and leaves.

Soil

While poinsettias are typically purchased already potted from a garden center or nursery, if you're planting (or replanting) a poinsettia, choose a well-draining peat-based potting soil.

In warm climates (zones 9 to 11), poinsettias can be planted into the landscape, thriving best in a well-drained, acidic to neutral soil.

Water

Water your poinsettia whenever the soil surface feels dry to the touch. Saturate the soil completely until water runs through the container's drainage holes, but do not let the plant sit in water. If the pot was wrapped in decorative foil, be sure to poke a few holes through the bottom to allow excess water to drain away.

Overwatering can kill your poinsettia: wilting leaves and rotted plant roots are usually signs of overwatering.

Temperature and Humidity

To keep your poinsettia blooming, maintain a temperature of 65°F to 75°F during the day. A slight drop in temperature at night will not hurt the plant. However, cold drafts, allowing the leaves to touch a cold window, or more importantly, a lack of adequate light, can injure leaves and cause premature yellowing and leaf drop.

Lack of humidity during dry seasons, particularly in winter, can be a problem for poinsettias. If your home tends to be dry, consider using a small space humidifier, or placing a dish of water nearby, to increase humidity levels by your poinsettia.

Fertilizer

Do not fertilize these plants during their blooming period. When keeping the plant throughout the year, you can begin fertilizing in the spring at half-strength when there's no growth, but not until then. Feed every three to four weeks until the plant is re-established.

Types of Poinsettias

Besides the traditional red bracts, newer hybrids have been bred in a variety of colors, including shades of white, cream, yellow, salmon, purple, burgundy, and pink. Note that some unusual colors, such as blue, are produced using dyes, and if the plant reblooms, bracts will be their natural color.

At any given time, there are at least 100 different poinsettia cultivars to choose from. Some recent favorites (along with some long-time standards) include:

• 'Christmas Eve': This is a long-time favorite with pure red flowers, known for its long color season.
• 'Plum Pudding': This is the first purple hybrid introduced to the market.
• 'Alaska White': As the name suggests, this is a pure white cultivar that blends well with red varieties.
• 'Jingle Bell Rock': ‘This variety is a mixture of cream and bright red with glossy dark green leaves.
• 'Candy Cinammon': This cultivar has dappled pink foliage, making for a softer appearance.
• 'Golden Glow': This soft yellow variety is compact and known to be more heat tolerant than other forms.
• 'Lemon Drop': This cheery variety has bright yellow bracts.
• 'Gold Rush': This stunning variety combines shades of pink and gold.
  

How to Get Poinsettias to Rebloom

If you want to grow your poinsettia throughout the year and force reblooming for the next holiday season, you must follow a very specific process throughout the year. Achieving rebloom is not easy, so don't be disheartened if you don't succeed on your first try. Follow this schedule for best results:

December to Early Spring

Water your holiday poinsettias, keeping them moist but not soaked. Then, starting in early spring, do the following:

1. Gradually decrease waterings, allowing the soil to dry out between waterings. Be careful that the stem of your poinsettia does not begin to shrivel—this is a sign the plant is too stressed and is dying.
2. In a week or two, when the plant has acclimated to this drying process, move it to a cool spot, such as the basement or a heated garage. Keep the temperature around 60 degrees Fahrenheit.

May

In mid-May, do the following:

1. Cut the stems back to about four inches and repot your poinsettia into a slightly larger container filled with new potting soil.
2. Water well and place the newly-potted plant in front of the brightest window you have, and once again keep it at a temperature of 65 to 75 degrees Fahrenheit.
3. Continue watering whenever the surface of the soil feels dry and watch for new growth.
4. Once new growth appears, begin fertilizing every two weeks with a complete fertilizer.

Summer

Come summer, move your potted poinsettia outdoors. Keep it in a partially shaded location and maintain your watering and fertilizing schedule.

1. In early July, pinch back each stem by about one inch to encourage a stout, well-branched plant. If left unpinched, the poinsettia will grow tall and spindly.
2. By mid-August, the stems should have branched and leafed out. Once again, pinch or cut the new stems, leaving three to four leaves on each shoot. Bring the plant indoors and place it near your brightest window.

October

Poinsettias are short-day plants, meaning their bud set is affected by the length of daylight. To rebloom, poinsettias need about 10 weeks with 12 to 14 hours of absolute darkness per day. You will have to artificially create these conditions and remain diligent. At the very start of October, do the following:

1. Keep your plant in complete darkness from 5 p.m. to 8 a.m.—any exposure to light will delay blooming.
2. Use an opaque box or other material to block out all light, including artificial light. Many people place their plants in a closet, but if any light gets through cracks or if you open and use the closet, the exposure to light will affect the bud set.
3. Move the plant back to the sunny window during the daytime and continue watering and fertilizing.

November and December

About the last week of November, stop the darkness treatment and allow the plant to remain near the window. You should see flower buds at this point. Stop fertilizing around mid-December. Keep watering and treat your plant the way you did when you first brought it home in bloom. If all has gone well, bracts should begin to show color.

Pruning

Poinsettias grown for a single season need little pruning other than pinching off faded leaves. Plants grown for rebloom, or transplanted into the landscape in mild climates, will benefit if they are pinched back frequently during the growing season to produce bushier plants.

Propagating Poinsettias

Most poinsettias are hybrid plants that do not produce genetically reliable seeds, so they are usually propagated by rooting stem cuttings. This is best done by taking cuttings in early summer, as new growth is starting. Here's how to do it:

1. Using sharp pruners, snip 3- to 6-inch tips from new green growth.
2. Dip the cut end in powdered rooting hormone, then plant in a small pot filled with standard commercial potting mix.
3. Enclose the planted cutting in a loosely secured plastic bag to hold in moisture, then set it in a spot with bright indirect light, but out of direct sunlight.
4. After about a month, the cutting should develop roots. When you notice new leaf growth, remove the plastic bag and continue to grow the rooted cutting, repotting as necessary when it fills its pot.

Common Pests & Plant Diseases

Like many houseplants, poinsettias are susceptible to a variety of diseases and pests, including fungus gnats, whiteflies, thrips, mealybugs, and powdery mildew. If you notice signs of an infestation or illness, remove the affected area of the plant immediately and treat with an insecticide or fungicide until all signs of problems have disappeared.

Common Problems With Poinsettias

While caring for your poinsettia to encourage it to rebloom, be on the lookout for the signs of leaf and root rot problems described here.

Leaves Turning Yellow

Leaves will turn completely yellow or develop yellowness around the veins of lower leaves if the plant is stressed. There are many reasons for yellowing leaves:

• The plant isn't getting enough magnesium or molybdenum (an essential trace mineral) and needs soil pH to adjust to above 5.5.
• The plant is being over-fertilized.
• Powdery mildew is starting to form on the leaves and needs fungicide.
• The potting mix is too acidic.
• The plant is overwatered, suffering from low light conditions, or low temperatures.

If leaves have small spots with yellow halos, the plant has scab, which requires a fungicide application.

Stems and Leaves Turning Brown

Brown spots form on the plant in various places if it has canker, which might be helped by removing affected portions of the poinsettia. Stems will turn brown or black if the plant has root rot. Remove infected portions of the plant and try to repot the remaining healthier parts in clean soil and clean pots using sterile gardening tools. Apply a fungicide to the plant for protection.

Plant Leaves Falling Off

When a poinsettia defoliates, it doesn't spell good news and can lead to the death of the plant. It means that the poinsettia has serious canker or severe root rot from being underwatered, overwatered, or overfertilized. If some leaves are falling, the plant might also need a bit more light.

From: thespruce