The Ultimate Poinsettia Care Guide for Christmas and Beyond

What plants do you associate with Christmas? Sure, a Christmas tree might be your first answer, but I'm betting a classic Poinsettia won't be far behind. Technically a Euphorbia pulcherrima, the common name we know them by was named after Joel Roberts Poinsett, who bought the Poinsettia to the USA from Mexico in the 1830's. Other common names are the Lobster Flower and Flame Leaf Plant. 

This gorgeous statement plant is like a living Christmas ornament, with bright red flower bracts, dainty yellow flowers and green leaves beneath. They do also flower in other colours, including creamy white, orange, pink, and even variegated. But it's the classic red and green that remain the most popular for Christmas, and the easiest to find in stores. 

Flowers or leaves?

Those coloured Poinsettia leaves are not actually leaves at all. Technically they aren't flowers either. They are bracts. Like Poinsettia, the white 'flowers' on a Peace Lily are bracts also. It's only when Poinsettia flower that you see their colours. For the rest of the year when not in bloom, the plant is green. 

Bracts are a type of modified leaf that surround the flowers and have pigments that give them those gorgeous colours. They are winter bloomers. If your part of the world has Christmas in Summer, clever growers have forced them to bloom for you for the holidays.  

When they finish flowering, or have been pollinated, the colourful bracts will drop off, leaving the green leaves behind. However, just like other flowering indoor plants such as orchids and Peace Lilies, no more flowers (or coloured bracts) doesn't mean your Poinsettia is dying or dead. Instead of throwing it away, you can keep it as a green plant and with the right care, get it to bloom again for you in winter, however that can be a challenge!

Are Poinsettia hard to care for?

As popular as they are as both a gift or to buy for yourself during the holidays, they are not the same care as most houseplants, so do need to be looked after a little differently to what you might think. That doesn't mean Poinsettia are difficult to care for, just different. Often treated like a bunch of flowers and only kept for a few weeks over Christmas and New Year's, with the right care you can actually grow them as perennials that will keep growing (and bloom again), for multiple seasons, instead of as annuals that get thrown away. 

How long do Poinsettia flower for?

Given the right care, Poinsettia usually keep their gorgeous colours and flower for 2 to 3 months.

Light requirements for Poinsettia kept indoors vs outdoors

Poinsettias love warm, bright conditions, and depending on what zone you're in, can be grown indoors or outside. You might have read online to give Poinsettia up to 14 hours complete darkness overnight coupled with just 6 or so hours of bright, indirect light during the day, however that's part of what's required to get them to bloom. But once in bloom - which is how you will have likely bought yours if it's full of colour right now - the light requirements are different.

When full of colour in bloom and kept indoors, give Poinsettia plenty of bright but indirect light. They are not low-light plants. In too dark a spot they can loose colour with the bracts turning green, or even start dropping leaves.

It's best to avoid direct sun hitting the bracts or leaves in summer during the hottest parts of the day, but a little weaker early morning or late afternoon sun is normally okay. In winter when in bloom and kept indoors, direct sun for a good part of the day is often fine, but even then I prefer to stick to the weaker morning sun. 

Kept outdoors, a roughly half full-sun half-shade position makes a good spot for Poinsettia (and shelter from strong wind is essential). When grown in too dark a spot outdoors, they're unlikely to flower or give you those gorgeous colours in winter.

[above] Poinsettia come in more colours than just red, such as this red and creamy white variegated hybrid.

[below} Poinsettias also come in shades of orange, pink, creamy white and more.

 

What's the ideal temperature range for Poinsettia?

Poinsettia are notorious leaf droppers when exposed to temperature extremes. Aim to keep your Poinsettia between 18 to 21 degrees Celsius (that's 65 to 70 degrees Fahrenheit) if you can, especially during their journey home. If Christmas where you are coincides with Winter, ask for some plastic wrap to protect your Poinsettia from the cold between the garden centre and the car, and again between the car and home. If you get a Summer Christmas like we do here in New Zealand, beware blasting your air con in the car on the way home.

In general, you want a spot where the temperature stays pretty regular, rather than fluctuating a lot or temperature extremes. It's best to avoid being too near fireplaces and air-con units, fans, heat ducts and similar.

Avoid drafts!

Another common cause of often dramatic leaf drop in Poinsettia is drafts. Like most houseplants, airflow is still needed when kept indoors to avoid the usual low airflow related problems like powdery mildew and root rot, but it's best to position your Poinsettia out of the path of strong drafts. Avoid spots such as doorways and by open windows with strong airflow, or in the direct path of your air-conditioning.

Poinsettia watering requirements

Another aspect of poinsettia care that can get confusing is watering. A lot of advice online will tell you to keep your Poinsettia on the dry side, that they are very prone to root rot, and over-watering is their worst enemy when kept indoors.

Although it's true they are more prone to root rot than some, the reason for being paranoid about over-watering is in some parts of the world Poinsettia are a winter plant. However, if you're in a part of the world where Christmas coincides with Summer, you may well have bought your Poinsettia at the hottest time of year. That's when following the advice to be paranoid about watering too much can instead cause a quick, wilted death from under-watering instead!

In Summer, maintain your Poinsettia lightly moist. Don't let them fully dry out before watering again. I treat my Poinsettia similar to my Peace Lilies. When you do water, water thoroughly so the entire substrate is evenly saturated to the top. A fine yet light, free-draining mix with medium water retention is great (more coming up about the ideal substrate below).  

In Winter however, let your Poinsettia dry out more before watering again. I wait until they're about a 1/3rd dry, but again, best to water again before they fully dry out. And at all times of year, avoid water-logged soil that stays wet too long. Let your Poinsettia dry out partially between watering and avoid them ever sitting in water. No wet feet!

What's the best substrate for Poinsettia?

Indoors, I like to use a rich, fine, free-draining mix. Ideally a blend with medium water retention that doesn't dry out too fast, but is still light and 'fluffy' with plenty of air space to maintain a nice balance of moisture and air for happy roots. In pure soil or peat it can can too heavy and compact, retain too much moisture and not enough air.

I like the Wildvine Houseplant Blend which is soil-based but also includes perlite, fern fibre and coco chips to add air and increase drainage. Another favourite is the peat-based Bio Leaf African Violet Blend which is the same one I use for my Peace Lilies (I find my Peace Lilies and Poinsettia like similar conditions). In Bio Leaf the peat is broken up with perlite and vermiculite to increase the drainage and fluffy-factor.

To keep up with their preference for never fully drying out, growers will often pot Poinsettia in a soil-based or peat-based mix. You may find that is too compact and holds water too long in normal indoor conditions at home, so if needed (especially in winter), repotting will help avoid the risk of root rot from waterlogged soil. It's not a must though and I prefer not to repot when in flower or it can shorten how long your Poinsettia will flower. If airflow, light and temperature are all good, your Poinsettia shouldn't stay wet too long even in the 'wrong' mix, and you can wait to repot after flowering has finished or when your plant could do with going up a size (that's if you're going to keep it after flowering of course). 

No matter what substrate your Poinsettia is in, drainage is a biggie. If your plant came to you in a pot without drainage holes, consider repotting if you want to prolong how long it lives - or just stab some holes in the pot (depending on what it's made from - safety first!). If the pot it's planted in has drainage, but the cover pot does not, remove your Poinsettia to water it, so that excess water doesn't pool in the cover pot and risk root rot.

Can Poinsettia be used as cut flowers?

Yes, they make beautiful cut flowers. But there is a method to how you cut Poinsettia because of their milky, sticky sap. Trim with sharp shears for a clean cut. Place the freshly cut stem in hot water for 20 seconds or so to help seal in the sap. Then pop the stem in cold water in a vase on display, or use florist foam.

If you have sensitive skin or a Latex allergy, avoid the sap getting on your skin or in your eyes. It's best to wear gloves just in case and always wash your hands if you touch the sap. Wipe shears clean pretty quickly afterwards also, otherwise that sap can go tacky and even stickier, making it hard to remove off tools later.

Are Poinsettia toxic or poisonous?

An Ohio State University study found Poinsettias are better classed as mildy irritating if eaten, rather than toxic or poisonous, and you'd have to eat a LOT to cause even a sore stomach. But it's their milky sap which can cause an allergic reaction such as itching for some when touched, particularly if you're sensitive to Latex. When pruning or repotting your Poinsettia, gloves are a good idea. Wash your hands and avoid getting the sap on your skin or in your eyes.

Like pruning Ficus, I also find it best to wipe down your tools pretty quickly after cutting Poinsettia, as that milky sap can get sticky and is easier to clean off when fresh. And if you have curious kids or pets that might consider an exploratory bite, although it's very unlikely to cause a reaction at all (it's estimated a good 500+ leaves would need to be consumed to cause a reaction for most), by all means pop your Poinsettia up high out of reach if you're worried. 

What zones can Poinsettia grow in outdoors?

Poinsettia can be grown outdoors in zones 9 to 11. In New Zealand we vary from zone 5a to zone 12a. In general, Auckland and north is zone 10 with the Far North being zone 11. The rest of the North Island averages zone 9 (or 8 as you go more in-land). The South Island averages zone 8 with coastal regions zone 9. Poinsettia don't tolerate frost or cold temperatures, so you may prefer to grow yours in a container and bring it indoors or under cover for part of the year.

Can Poinsettia go outside after Christmas?

Absolutely, provided you're in zones 9 to 11 and have a good spot for them, once your Poinsettia has finished blooming inside, you can plant it or shift it outside. Pick a part-sun, part-shade position that is sheltered. Their branches are relatively brittle so strong wind isn't tolerated well. If you keep them in a pot, you can bring them in again to enjoy when they re-bloom. Getting them to rebloom can be a bit of a challenge, but that's for another article!

Why are my Poinsettia leaves falling and dropping off?

Poinsettia are known as leaf droppers, and sometimes at a dramatic speed. They prefer 'medium' conditions: warm, bright, humid and medium moisture. Fall too far outside those parameters, or expose them to a sudden change in any of those conditions, and leaf drop can start. I find if it's not over- or under-watering, the other main causes are a temperature spike, either a sudden change to cold or hot, or being left in a draft, such as in the path of your air conditioning. Go through the ideal conditions above and check them off one by one to find out the most likely cause.

Do I need to fertilise my Poinsettia?

Yes and no. If you plan on it moving to the rubbish bin when it finishes blooming, then I wouldn't worry about feeding. However, if you plan to keep your Poinsettia after it's finished flowering, you can start feeding a foliage or growth fertiliser when flowering finishes. For flowering I use GT Flower Focus and for foliage I use either Plant Runner Indoor Plant Food or GT Foliage Focus for mine.

What are the flying bugs around my Poinsettia?

Like Peace Lilies, Poinsettia prefer an organic, moist substrate. So do pests like Fungus Gnats! Whiteflies can also be attracted to Poinsettia. For both flying pests I just pop a uBloomd Green Sticky Trap in the pot to catch any adult flying pests. For Fungus Gnats larvae in the soil you can also make 'Mozzie Tea' and water that into the soil (with no harm to the plant or any good soil bugs). Here's how to get rid of Fungus Gnats once and for all >

Why are my Poinsettia's leaves turning brown?

Poinsettia are prone to bract edge burn, where the edges of the bracts (that's the coloured, modified leaves around the flowers), become brown and can die off. It starts as brown spots around the edges of the bracts or browning at the tip. The initial cause is often a nutrient deficiency, however it can lead to Botrytis, a fungus that can quickly spread. Good airflow and avoiding very high humidity (90% plus), also help avoid Botrytis taking hold. As does avoiding leaving your Poinsettia sitting in water or in waterlogged soil.

One of the common causes for bract edge burn is a simple calcium deficiency. Even if you fertilise, the majority of fertilisers lack calcium. Two that do include calcium are Growth Technology and Dyna-Gro. A calcium deficiency can cause blossom end rot and bud blast in Hoyas and Orchids. 

Browning can also be caused by fertiliser burn from over-fertilising or a build-up of minerals salts from tap water or fertiliser over time. Choose a reduced-salt fertiliser (Growth Technology for example avoids chlorides, urea and sodium, three of the highest-salt-index ingredients in most fertilisers), shifting to a low-nitrogen flower fertiliser, and feeding using the little-and-often Weakly Weekly Method can all help.

Why is my Poinsettia wilting?

There can be other causes, but like Peace Lilies, Poinsettia can be drama queens when it comes to water in particular. In response to under-watering, whether it's from watering too lightly, or not watering often enough, they can rather dramatically wilt, or even drop their leaves. If you see wilting as well as curled leaves that's also a combo often caused by under-watering.

In winter, water again when the soil's about 50% dry. In summer, maintain the soil lightly moist at all times if you can, or water again when the soil's no more than 1/4 to 1/3rd dry. The right substrate helps immensely. One that dries out too fast, like a succulent or aroid mix, will often lead to wilting. Go for a substrate with a decent amount of water retention, usually something soil-based or peat-based instead to help avoid your Poinsettia fully drying out too fast and wilting.

Happy Holidays!

If Poinsettia are a Christmas classic you get or gift every year, and you're reading this during the holidays, I hope you're having a wonderful Christmas and New Years and that my Ultimate Poinsettia Care Guide will help keep your Poinsettia brightening up your home for the holidays for months to come.

Happy planty holidays and happy growing,
Anna @lovethatleaf :)