Don’t Throw Away Your Poinsettia: How to Keep it Thriving for Months

Around the globe, poinsettias enliven the holiday season. Wild specimens of Euphorbia pulcherrima originate in Mexico and Central America, where they grow to 15 feet tall. The tropicals have an ancient history of cultivation, beginning with the Aztecs. 

The colorful, compact plants we celebrate today are available in hundreds of colors and patterns, from bright red to white to pink to gold, with merry names like ‘Jingle Bells,’ ‘Peppermint Ruffles,’ and ‘Plum Pudding.’ Elegant varieties like ‘Autumn Leaves,’ ‘Lemon Glow,’ and ‘Candy Wintergreen’ sparkle during the season.

Not ready to part with your poinsettia after the holidays? Extend its life as a green houseplant or garden specimen where hardy (USDA zones 9-11). With the right care, like pruning, and the best light, water, and temperature, you’ll have color another year. Enjoy the tropicals as a houseplant, move them outdoors in summer, and await reblooming!

Post-Bloom Care

Poinsettias give their full color anytime from November through January, depending on the variety. The colorful bracts (leaves that look like blooms) show for four to six weeks. After the splash, the leaves wilt, dry, and drop. The plant prepares to enter a natural rest period or dormancy. A well-cared-for selection rebounds after the brief recharge period, and new growth emerges with spring’s warming temperatures.

As leaves drop, pruning is beneficial to foster full, bushy plants when new growth flushes. We’ve seen those leggy spindles that poinsettias can become; a little cutback, as well as periodic pinching, prevents this. March and April are good times for a healthy trim.

Cut back stems by about half and as low as five inches. Work with each stem, clipping it just above a leaf node. Leaving some length on the stem ensures nodes remain to produce more stems and bracts.

In early summer, pinch back the growth tips on each stem to promote side branching. Pinching leads to full, fluffy specimens and more of those colorful bracts. Do a final round of pinching in late summer (August or September).

The Right Light

These tropicals need lots of bright, indirect light to flourish. Insufficient light doesn’t support the energy needed to grow and initiate color. Six hours of bright light, out of the sun’s direct rays, are optimal.

Place poinsettias near a bright window; east or southwest-facing are prime exposures. In nature, they grow in dappled light under shade canopy. An hour or two of morning sun works well, but too much direct sunshine, especially afternoon rays, can scorch the thin foliage.

Poinsettias are photoperiodic and respond to shorter day lengths (and longer nighttime darkness) to develop the showy bracts. Along with cool nighttime temperatures from September on, they need 12 hours of darkness for the best coloration. 12 to 15 hours of total darkness over six to eight weeks is the key. 

If your pot isn’t in a completely dark nighttime space, there are some measures to provide the necessary dark hours. To provide the essential darkness to initiate color, use a light-blocking cover like a cardboard box from early evening to morning. Or, move them to a closet in the early evening, covering the door’s seal so no ambient light seeps in.

When to Water

Poinsettias do best with drying out a bit between waterings. Aim for evenly moist, but not soggy, soils. A soil touch test is the best way to tell, watering when the top two inches of soil feel dry (a knuckle or two deep). The pot will feel lighter, too. Watering is usually about once a week, depending on the growing environment. Err on the dry side rather than overwatering, but try to prevent wilting or allowing soil to dry out more than a few inches.

Water fluctuations are a top cause of losing viable bracts. It’s especially easy to do in the busy holiday time – over or underwatering as we enjoy our new plants. In nature, the tropicals absorb plenty of rain and moisture from the air, followed by dry spells. They don’t tolerate prolonged periods of oversaturation or soggy soils.

Overwatering damages roots and leads to their inability to uptake water and nutrients necessary for flowering. Underwatering causes the plant to enter preservation mode, directing any moisture to roots and dropping leaves in the process.

At each session, water deeply until it flows from the pot’s drainage holes. Leave the pot in the sink to drain, or remove its catchment saucer after a short time so the water doesn’t sit. Make sure to remove the container from its decorative sleeve or outer pot when watering to allow it to fully drain. During dormancy, watering will lessen, but continue with the soil touch test.

Indoor and Outdoor Temperatures

Poinsettias grow best in temperatures between 60-85°F (16-29°C). Temperatures below 50°F (10°C) challenge their growth. They enjoy warm months outdoors but bring them indoors to overwinter in cool climates. While hardy to zones 9-11, they may survive winters in zone 8 with a thick layer of mulch in a protected area.

Like short daylengths and longer darkness, cool temperatures support color initiation. Nighttime temperatures in the 60s (~16°C) are optimal in the fall as bracts prepare to color up. Avoid temperature swings and drafts, which can affect foliage and roots.

Drastic temperature fluctuations are common as we move plants this time of year, but the resulting stress causes leaf drop. The tropicals benefit from cool nighttime temperatures to initiate flowering, but quick extremes halt development. 

To avoid sudden cold blasts or heat drafts, keep containers away from heating and air vents, open doors, space heaters, and fireplaces. 

Humidity

Humidity is another important consideration for poinsettias as we heat our homes in winter. A level of around 50% works well, and while this is average in many households, winter can vary. In the wild, they enjoy high humidity at 50-70%.

To increase humidity, group them near other houseplants. Or, place its container near a tray of pebbles filled with water. The water evaporates around the rocks, adding ambient humidity that poinsettias benefit from. Add more water as needed.

Fertilize

Poinsettias don’t need fertilizing when they’re in color. As they flower and then enter dormancy, hold off on fertilizing. Begin when new growth appears, and opt for a balanced fertilizer like a 5-5-5 liquid or granular.

Continue applications during the warm, active growing season. Granules usually last a couple of months, while liquid feeds absorb more quickly and require more frequent applications. Use liquid feeds every other watering session, according to the directions. Reduce fertilizer applications by half in late summer and stop by early fall.

Repot

After dormancy and as new growth begins to flush, the bloomer may be ready for a larger pot in late spring to early summer. If your plant is drying out more quickly and roots are evident through the drainage hole, prep a pot one size (two to four inches) larger. Gently slip the poinsettia from its original pot to check the roots. If they fill the current pot, going up a size will promote root and leafy growth.

Repotting refreshes the nutrition and aeration of potting soil, too. Use a high-quality potting mix to promote good drainage.

Early Fall Essentials

After providing all the right care leading up to the flowering season, here are the final touches to enjoy the bold, colorful bracts:

• Do a final round of pinching back growth tips in early September.
• Bring poinsettias indoors when temperatures near 50°F (10°C). They’ll survive lower temps but won’t endure a freeze without protection.
• Place them in a bright spot with at least 12 hours of nighttime darkness for up to eight weeks. Cool nights in the 60s (~16°C) and warm days in the 70s (~21°C) work well.
• Water when the top two inches of soil are dry, and the pot feels light. Water deeply, and allow pots to drain fully.
• Keep out of heated drafts or cool blasts.
• By November and December, your poinsettia will show signs of rich color. Deck the halls and enjoy its long bloom time, worthy of your hard work!